Abstracts

  1. Rubber and LCLUC in Mainland Southeast Asia
  2. Do rubber plantations threaten soil biodiversity? The case of Rubber plantations in Thailand
  3. Obtaining rubber plantation age information from very dense Landsat TM & ETM+ time series data
  4. Linking Landsat 8 spectral reflectance and floristic pattern of Xishuangbanna’s tropical rain forests
  5. An analysis of land use change and its driving factors in the Naban River Watershed
  6. The pattern and dynamics of rubber monoculture expansion in Xishuangbanna, SW China
  7. Combining sacred natural sites to develop effective conservation system in Xishuangbanna
  8. Effects of landscape configuration on wild bee diversity in a rubber-dominated landscape of southern Yunnan (China)
  9. Ecological changes along the transition from annual crops to rubber plantations in mountainous landscape of Northern Thailand
  10. Impacts of converting natural forest to rubber plantation on soil microbial communities
  11. Integrative profiling of bee communities in habitats of the Naban reserve of Xishuangbanna
  12. Ecological impacts of rubber plantation on ant fauna: a case study from monsoonal tropics of Xishuangbanna, Southwest China.
  13. Rubber plantations and arthropod communities in Xishuangbanna; novel habitat or new threat
  14. The Economics of Smallholder Rubber Farming in a Mountainous Region of Southwest China: Altitude, Ethnicity and Risk
  15. Greenhouse gas emissions in rubber plantations
  16. Heveadapt: How can Thai rubber smallholders face global challenges?
  17. Farmers’ attitudes to promoting sustainable rubber cultivation: Evidence from Xishuangbanna, China
  18. Assessment of Governance Mechanisms, Livelihood Outcomes and Incentive Instruments for Green Rubber in the Lao PDR and Myanmar
  19. Labor management in mature rubber plantation of farmers in Northeast Thailand
  20. Exploring Futures of Xishuangbanna: Livelihoods, wellbeing and adaptation
  21. Overview and Major Constraints of Natural Rubber Industry in Myanmar
  22. Three main nutrients removal content in rubber yield for optimal fertilizer supply guideline
  23. Soil gaseous carbon flux in rainforest and rubber plantations
  24. Seasonal occurrence of pesticides in a watershed of Xishuangbanna, Yunnan, China
  25. Exploring the deep frontier: rooting patterns of rubber trees in Southeast Asia
  26. Comparison of transpiration characteristics in different aged rubber plantations
  27. Nitrogen fertilization effect on N2O emissions from a typical rubber plantation
  28. Field comparison of water use in 5 immature rubber clones
  29. Bird Monitoring for Green Rubber
  30. Distribution of aggregate size fraction and associated soil organic carbon in rubber–based agroforestry systems: implication for land use
  31. Soil Water Repellency in Different Types of Rubber-Based Agroforestry Ecosystems in Xishuangbanna
  32. Farm Types and Farmer Motivations to Adapt: Implications for Design of Sustainable Agricultural Interventions using the Example of Rubber Plantations in South West China
  33. Community structure of soil mesofauna in different stages of rubber plantation
  34. Natural Rubber Research in Colombia: advances in process standarization in Bajo Cauca Antioqueño
  35. Soil chemical properties and leaf nutrient contents in chronosequence of the rubber plantation in NE of Thailand
  36. Measuring Leaf Area Index in Asian Rubber Plantations – A Challenge
  37. Ecosystem services and biodiversity of rubber plantations – a systematic review
  38. Nutrient losses by erosion in upland immature Para rubber plantation of Northern Thailand
  39. Can soil erosion be reduced by allowing understory vegetation in rubber plantations?
  40. Analysis on Annual Diameter Growth Patterns of Rubber Tree Variety in Hainan Island,China
  41. Spatial and seasonal variation in soil respiration along a topographical gradient in rubber plantations and natural forest in Xishuangbanna, SW China
  42. Taxonomic revision and phylogenetic analyses of rubber powdery mildew fungi
  43. Community analysis of litter ants in forest fragments and rubber plantations in Xishuangbanna
  44. Land Use and Impact of Soil Aggregate Size
  45. Impact of Three Rubber Agroforestry Systems on Soil Functionalities and Diversity
  46. Impacts of fertilizers application on CO2 emissions in Rubber (Hevea brasilensis) Plantation in Xishuangbanna, SW China
  47. Mekong Sentinel Landscape: Monitoring social-ecological processes at landscape scales
  48. Livelihoods and gender in rubber landscapes in China and Laos
  49. Effectiveness of protected areas in preventing rubber expansion and land conversion in Xishuangbanna
  50. Taxus mairei as potential intercropping plant in rubber plantations
  51. Rubber agroforestry systems in Indonesia and Thailand for a sustainable agriculture and income stability.
  52. SURUMER – A framework for sustainable rubber cultivation
  53. Flemingia macrophylla introduced to the rubber plantation mitigates soil acidification processes and improved soil available phosphorus in Xishuangbanna, Southwest China
  54. Could sustainable agricultural practices buffer the impact of rubber tree monocropping on soil biodiversity? Case of rubber plantations in Northeast Thailand
  55. Are rubber-based agroforestry systems effective in controlling rain splash erosion?
  56. Mitigating Monoculture Rubber Plantation with Analog Agroforestry System
  57. How does interspecific competition for water in rubber agroforestry help improve the water use of rubber trees?
  58. Effects of biochar addition on soil properties and carbon sequestration of rubber plantation in Xishuangbanna, SW China
  59. Modelling the impact of rubber expansion on carbon stocks in landscape
  60. Ecological process-based modeling for predicting rubber tree growth and latex yield under climate change
  61. Management of herbicide usage in rubber plantations with help of modeling erosion and crop growth
  62. Riparian buffer strips as measures to reduce fine sediment infiltration into rivers in an agricultural dominated area in Southwest China
  63. The effect of monoculture rubber plantation expanding on stream flow in Xishuangbanna, China
  64. Combining multi-disciplinary Ecosystem Service Assessments in Rubber – challenges and boundaries
  65. How meta-data analysis and data visualization can help us make better decisions for sustainable rubber cultivation?
  66. Rubber Booms, Land Policies and Land Grabs in Cambodia, Lao PDR and Myanmar
  67. Using agroforestry to diversify smallholder monoculture rubber plantations: A participatory approach to development
  68. Enriching rubber with native tree species – a first assessment of the SURUMER demonstration sites
  69. Rubber agroforestry systems in Thailand
  70. Between rubber cultivation and nature conservation: Asian elephants and other wild mammals
  71. Promoting rubber seed oil as a healthy edible oil for humans in China
  72. Assessing the welfare effects of enhanced ecosystem services provided by tropical rainforests: the example of sustainable rubber cultivation in Xishuangbanna, SW China
  73. Co-management of transdisciplinary processes: experiences from the SURUMER project
  74. Stakeholder analysis in support of joint land use decision making: Case from Xishuangbanna, Southwest China
  75. Great Expectations: Chinese Investment in Laos and the Myth of Empty Land
  76. Using Rubber Agroforestry for Forest Conservation in Indonesia


Rubber and LCLUC in Mainland Southeast Asia

by Jefferson Fox1
1 East-West Center

The mountainous region of mainland Southeast Asia (MMSEA) harbors a wealth of natural resources, including globally important forests, multiple plant and animal species, and the headwaters of major rivers. For centuries, farmers in this region practiced diverse systems of shifting cultivation that produced a unique landscape mosaic combining small agricultural plots with secondary forests. Over the last few decades national policies have driven the expansion and upgrading of road, electricity, and telecommunication networks, and the commoditization of agriculture. Attracted by the opportunity to convert traditional farming areas into high-value commercial operations, outside entrepreneurs, corporations, and governments have sought to gain control of land in the region through schemes ranging from joint ventures with local farmers to outright dispossession. Some farmers have enhanced their income by switching to the intensive production of cash crops. Others have been forced into contracts with unfavorable terms or have lost their land entirely. While more intense agricultural production may pose a threat to fragile local environments, it is not possible to turn back the clock. Rubber plantations, in particular, have proven highly profitable. This talk will review findings from a recent NASA funded project that mapped land-cover change in MMSEA more accurately than had been previously accomplished. The presentation will also discuss land, income and labor implications of these changes at study sites in Northeast Cambodia and Southern Laos. Finally, the talk will discuss potential implications of the fall in rubber prices for land-cover change.


Do rubber plantations threaten soil biodiversity? The case of Rubber plantations in Thailand

by Alain Brauman1
1 IRD

With more than 25% of all the species, soil biota represents a biotic frontier since less than 10% of soil species are already described. Moreover soil biota, as it controls organic matter turnover rates, nutrient cycling and soil structural stability, plays a major role on soil health, i.e. the capacity of soil to support agricultural production and further ecosystem services. Nowadays, the impact of tree plantations such as rubber plantation (RP) on biodiversity remains a controversial issue, but few studies take into account the soil biodiversity. This study will present the impact of RP in Thailand on soil biota diversity and functions linked to ecosystem services. The scientific objective of our four years study was to specify the main drivers of biodiversity modifications within land use changes (cash crop to rubber), plantations age (immature-mature), agricultural practices (level of intensity of agricultural practices). In all the RP, soil taxonomic and functional biodiversity (macrofauna, nematodes and bacteria) were assessed together with main physico-chemical soil properties. Our results showed that (i) the age of the plantations was the main driver controlling soil biodiversity changes (ii) from young to mature RP, we observed a partial recovery of soil biodiversity after land uses changes, but a lost of this resilience after 3 full cycles from young to mature RP (3 x 25 yr), (iii) compared to cassava, RP seems a more suitable alternative for improving soil health (iv) a negative impact of intensive management (tillage, intercropping etc.) on soil biodiversity and abundance but this impact was really significant in young rubber plantation. As a conclusion, if RP does affect the soil biodiversity and its related functions, this impact could be reduced when the agricultural practices favor short term plantations, and promotes plant diversity in mature plantations.


Obtaining rubber plantation age information from very dense Landsat TM & ETM+ time series data

by Philip Beckschäfer1
1 Chair of Forest Inventory and Remote Sensing, Georg-August-Universität Göttingen, Büsgenweg 5, 37077 Göttingen, Germany

Determining the age of rubber tree plantations (Hevea brasiliensis) is of great interest to plantation managers and land-use decision makers as it allows, among others, for reliable forecasts of resource availability. The acquisition of age information with field campaigns, however, is time consuming, laborious and expensive. Focusing on Xishuangbanna, China’s second largest rubber planting area, we therefore, present an approach that allows for a rapid assessment of rubber plantation age at regional scales applying very dense Landsat Times Series (LTS) satellite data. We used 272 Landsat TM and ETM+ surface reflectance images to generate annual best-available-pixel composites by selecting at each pixel location the lowest Normalized Difference Moisture Index (NDMI) observation. Annual composites were classified into vegetated and non-vegetated areas applying a global NDMI threshold of 0. As it is common practice to clear the land before a new plantation is established, the last year in which a pixel located in a rubber plantation was classified as non-vegetated was recorded as the year of plantation establishment. Comparing the resulting plantation age map with 96 verification data points, collected by visual interpretation of historical high resolution images in Google Earth, a Root Mean Square Error (RMSE) of 1.6 years was calculated, indicating the high suitability of the described approach to obtain accurate plantation age information. From the map we inferred that in 2015 48% of Xishuangbanna’s rubber plantations had an age suitable for latex tapping (8 – 25 years), 24% were too young to be tapped (<8 years) and 28% had already reached an age of reduced latex productivity and will probably be harvested for wood in the near future (>25 years).


Linking Landsat 8 spectral reflectance and floristic pattern of Xishuangbanna’s tropical rain forests

by Jie Zang 1, Philip Beckschäfer2
1 Chair of Forest Inventory and Remote Sensing, Georg-August-Universität Göttingen, Büsgenweg 5, 37077 Göttingen, Germany
2 Chair of Forest Inventory and Remote Sensing, Georg-August-Universität Göttingen, Büsgenweg 5, 37077 Göttingen, Germany

The rapid expansion of rubber tree plantations (Hevea brasiliensis) and cash crops across Xishuangbanna, China poses high pressure onto the biodiversity left in the remaining natural forests. A fast and efficient assessment of species richness is, therefore, needed to provide guidance and support prioritization of conservation efforts and to efficiently monitor protected areas. In this context we investigated the potential of multispectral Landsat 8 satellite imagery to generate indicators of floristic beta diversity. For the analysis we used data sets from species inventories that were independently conducted in two tropical forests in Mengsong and Mengla, Xishuangbanna. Per site, we described the variability in tree species composition across space with non-metric multidimensional scaling (NMDS) and subsequently regressed the spectral information recorded by the Landsat sensor on the NMDS axes scores using generalized additive models. This indirect gradient analysis allowed for evaluating whether a change in spectral reflectance can be attributed to a change in tree species composition. For both forest sites we found significant relationships of Landsat’s near infrared band with the NMDS ordination which explained 63% of the observed variability. Also the short wave infrared band appeared to be influenced by species composition as the NMDS ordination explained 67% and 41% of its variability in Mengla’s and Mengsong’s forests, respectively. The results indicate that the spectral information captured by Landsat 8 can potentially be used to assist in the monitoring of floristic biodiversity of tropical forests and to detect locations harboring species communities not yet protected by conservation areas.


An analysis of land use change and its driving factors in the Naban River Watershed

by Kevin Thellmann1
1 University of Hohenheim

The objective of this study is to determine and analyse recent land use/land cover (LULC) changes in the Naban River Watershed National Nature Reserve (NRWNNR) with a special focus on rubber (Hevea brasiliensis) cultivation and its driving factors. LULC changes have been analysed with ArcGIS using LULC maps of the NRWNNR from three points in time: 2007, 2013 and 2015. The Intensity Analysis method was used to assess the magnitude and intensity of LULC changes among ten LULC categories. A binary logistic regression model was built for each of the three time points to derive the influence of factors driving rubber LULC changes. Data on potential rubber driving factors has been collected from multiple sources and implemented in a spatially explicit way. 12 factors were used as 46 separate continuous or binary layers including biophysical data (e.g. slope, distance to rivers, etc.) and socio-economic data (population, per capita income, ethnicity, etc.). The intensity analysis revealed an annual change rate of 7.18% of the NRWNNRs total area in the study period, with apparently faster LULC change processes between 2013 and 2015. The logistic regression models differed in their number and kind of included driving factors and their accuracy. Among the most important driving factors for all three models were land under private tenure, having a positive effect on the occurrence of rubber areas, while state/non-village areas and increasing elevation were found to exert a negative influence. All models were proven to be statistically significant and have been validated using relative operating characteristics (ROC). The ROC values of 0.93, 0.84 and 0.85, for the 2007, 2013 and 2015 model respectively, indicate a satisfactory goodness-of-fit for each model. The model output equations have been used to create rubber occurrence probability maps in order to evaluate the model accuracies in a spatially explicit way.


The pattern and dynamics of rubber monoculture expansion in Xishuangbanna, SW China

by Chen Huafang 1, Zhuangfang Yi2, Dietrich Schmidt-Vogt 3, Antje Ahrends 4, Philip Beckschäfer 5, Christoph Kleinn 6, Sailesh Ranjitkar 7, Xu Jianchu 8
1 Key laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
2 World Agroforestry Centre (ICRAF) East and Central Asia, Kunming, China
3 Mountain Societies Research Institute, University of Central Asia, Bishkek, Kyrgyz Republic
4 Royal Botanic Garden Edinburgh, UK
5 Chair of Forest Inventory and Remote Sensing, Georg-August-Universität Göttingen, Göttingen, Germany
6 Georg-August-Universität Göttingen
7 ICRAF-ECA
8 ICRAF-ECA

The rapidly growing car industry in China has led to an equally rapid expansion of monoculture rubber in many regions of South East Asia. Xishuangbanna, the second largest rubber planting area in China, located in the Indo-Burma biodiversity hotspot, supplies about 37% of the domestic natural rubber production. There, high income possibilities from rubber drive a dramatic expansion of monoculture plantations which poses a threat to natural forests. For the first time we mapped rubber plantations in and outside protected areas and their net present value for the years 1988, 2002 (Landsat, 30 m resolution) and 2010 (RapidEye, 5 m resolution). The purpose of our study was to better understand the pattern and dynamics of the expansion of rubber plantations in Xishuangbanna, as well as its economic prospects and conservation impacts. We found that 1) the area of rubber plantations was 4.5% of the total area of Xishuangbanna in 1988, 9.9% in 2002, and 22.2% in 2010; 2) rubber monoculture expanded to higher elevations and onto steeper slopes between 1988 and 2010; 3) the proportion of rubber plantations with medium economic potential dropped from 57% between 1988 and 2002 to 47% in 2010, while the proportion of plantations with lower economic potential had increased from 30% to 40%; and 4) nearly 10% of the total area of nature reserves within Xishuangbanna has been converted to rubber monoculture by 2010. On the basis of our findings, we conclude that the rapid expansion of rubber plantations into higher elevations, steeper terrain, and into nature reserves (where most of the remaining forests of Xishuangbanna are located) poses a serious threat to biodiversity and environmental services while not producing the expected economic returns. Therefore, it is essential that local governments develop long-term land use strategies for balancing economic benefits with environmental sustainability, as well as for assisting farmers with the selection of land suitable for rubber production.


Combining sacred natural sites to develop effective conservation system in Xishuangbanna

by Zhai Deli 1, Xu Jianchu 2, Yang Yun 3, Guo Xianming4
1 Center for Mountain Ecosystem Studies (CMES), Kunming Institute of Botany (KIB), CAS, Kunming, China
2 CMES, KIB, China
3 Research Institute of Sciences, Xishuangbanna National Nature Reserve, Jinghong, China
4 Research Institute of Sciences, Xishuangbanna National Nature Reserve, Jinghong, China

Sacred natural sites have played important social and cultural roles, as well as biological conservation roles in many cultures around the world. Scientists have believed that scared sites acted as de facto protected areas. Due to cultural change, globalization, and national policies alter local forms of land management, sacred natural sites are decreasing, degradation, and vanish. The sacred natural sites have been effectively protected the natural forests in Xishuangbanna in history, however, we are not clear how many are still existence. To effectively protect the natural forests in Xishuangbanna, and to build effective biodiversity conservation corridors, we investigated the sacred sites in Xishuangbanna, and suggested the corridors. There are 930 sacred sites in Xishuangbanna, with the mean area 1.68ha. The new corridors mainly connected sacred sites with protected areas and existing natural forests. We suggested further social survey of people’s perceptions and values of these scared sites, and further assessments of the impacts of PAs development on sacred sites to build effectively traditional culture and religious based conservation system.


Effects of landscape configuration on wild bee diversity in a rubber-dominated landscape of southern Yunnan (China)

by Pia He 1, Konrad Martin 2, Zeqing Niu 3, Wencai Pu 4, Guanghong Cao 5, Manfred Kraemer6
1 Agroecology in the Tropics and Subtropics (490f), Institute of Agricultural Science in the Tropics, University of Hohenheim, D-70599 Stuttgart, Germany
2 Agroecology in the Tropics and Subtropics (490f), Institute of Agricultural Science in the Tropics, University of Hohenheim, D-70599 Stuttgart, Germany
3 Evolution of Functional Insect Groups, Institute of Zoology, Chinese Academy of Science, 100101 Beijing, China
4 Naban River Watershed National Nature Reserve Bureau, 666100 Jinghong City, China
5 Naban River Watershed National Nature Reserve Bureau, 666100 Jinghong City, China
6 Biological Collection, Faculty of Biology, University of Bielefeld, D-33615 Bielefeld, Germany

A major reason of forest loss and a serious threat to species diversity in Mainland Southeast Asia is the dramatic expansion of large scale rubber monocultures. In a region of southern Yunnan (China) affected by this change in land use, we selected 12 circular landscape sectors of 600 m radius each, covering different proportions of natural forest, rubber plantations and other land use types. Using modified pan traps and sweep-netting, wild bees were recorded from the center of the landscape sectors. We analyzed responses of all bees, solitary bees, honeybees and bumblebees to land use change in different circular distances and to natural flowering resources at the recording sites. We collected 98 bee species and 2621 individuals across all recording sites and the total collecting period of four months (April–July 2013), covering the beginning and the peak of the rainy season, which coincides with the main phase of the vegetation period after the dry season. Solitary bee species numbers significantly increased with forest area at nearly all spatial scales. Bumblebee species showed similar, but less pronounced responses, and honeybee species richness was not related to any landscape dy. Solitary bees negatively responded to rubber, in particular to areas in distances of more than 300 m around the recording sites. The total number of species and individuals increased with the quantity of flowering resources (number of flower units), but not with resource quality (number of flowering plant species). We conclude that the reduction of forest area and the expansion rubber plantations affects wild bee diversity, with stronger impacts on solitary bees than on honeybees and bumblebees. This may lead to unpredictable changes in bee-plant interactions and pollination services in landscapes where rubber monocultures are on the rise.


Ecological changes along the transition from annual crops to rubber plantations in mountainous landscape of Northern Thailand

by Margot Neyret 1, Henri Robain 2, Anneke de Rouw 3, Karn Trisophon4
1 École Normale Supérieure, Institut de recherche pour le développement
2 Institut de recherche pour le développement
3 Institut de recherche pour le développement
4 Land Development Department

In the past decades, economic development in South-East Asia led to increased environmental pressure. In particular, the transition from subsistence to cash and exportation crops, such as rubber tree plantations (Hevea brasiliensis) in mountainous regions such as Northern Thailand, is suspected to disturb hydrological regimes, to threaten biodiversity and to deplete carbon stocks. They might also favour soil degradation and loss of fertility, especially for sloping lands subjected to erosion. Weeds fulfil a wide range of ecosystemic services. They support biodiversity at higher trophic levels, and increase soil stability and erosion control. Yet, ongoing agrarian intensification might be detrimental to weeds and their associated services. Thus, enhanced management of weeds communities might be an effective contribution to improving erosion control in threatened areas. We investigated relations between weeds communities’ abundance and composition and soil physical properties along a transition from annual crops (maize, upland rice) to perennial rubber tree plantations (young plantations with maize intercrop, mature plantations). The study sites were located in Huai Lang, Chiang Rai province in Northern Thailand. We found that at the time of sampling (March), rice fields had the most diverse and abundant communities. All fields were dominated by two species, Ageratum conyzoides and Conyza sumatrensis. We identified three types of weeds communities associated to differences in land-use types and soil properties. Interestingly, plant density interacted with soil moisture and bulk density with distinct and sometimes opposite trends when considering different community types. Altogether, we showed that the composition of plant communities plays an important role in the interactions between weeds, land-use type and soil properties. Further research is needed to determine the seasonality and nature of weeds-soil interactions by investigating rooting systems and implementing experimental plots to compare different managements and to quantify their influence on soil physico-chemical properties controlling erosion processes.


Impacts of converting natural forest to rubber plantation on soil microbial communities

by Jutamart Monkai 1, Kevin D. Hyde 2, Jianchu Xu 3, Peter E. Mortimer 4, Rhett D. Harrison 5, Stefanie D. Goldberg6
1 Centre for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
2 Center of Excellence in Fungal Research, Mae Fah Luang University, 57100 Chiang Rai, Thailand
3 Centre for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
4 World Agroforestry Centre, East and Central Asia, Kunming 650201, China
5 World Agroforestry Centre, East & Southern Africa Region, 13 Elm Road, Woodlands, Lusaka, Zambia
6 World Agroforestry Centre, East and Central Asia, Kunming 650201, China

The conversion of tropical forests to monoculture rubber plantations is common throughout China and Southeast Asia. This study aimed to focus on the soil microbial community response when natural forest is converted to rubber plantations. We examined the biomass and composition of the soil microbial community using phospholipid fatty acids (PLFA) analysis of soil from adjacent forest types: natural forest, young rubber plantations (where trees have not yet been tapped for their latex) and old rubber plantations (after tapping). The conversion from rainforest to rubber plantation significantly changed soil microbial biomass and community composition across plantation ages. Rubber plantations, and especially older plantations, had a higher relative abundance of fungi (18:1w9c) than natural forest. PLFA microbial biomass of all functional groups including actinomycete, arbuscular mycorrhizal fungi, fungi, gram negative bacteria, gram positive bacteria, soil invertebrates, non-specific PLFA and total PLFA markedly decreased in both young and old rubber plantations after forest conversion. After forest conversion, changes in microbial community composition were greater in old rubber plantations compared to young rubber plantations. Moreover, the shift in microbial community composition varied depending on the season: changes in bacterial community composition were greater in the wet season than in the dry season, changes in fungal community composition were greater change in the dry season than in the wet season. pH, total phosphorus, sand content, clay content, soil moisture and soil temperature were the most important factors in shaping the soil microbial community across forest type. Our findings highlight the consequences of forest conversion to rubber plantations for soil microbial communities and the importance of sustainable rubber management practices to improve soil health.


Integrative profiling of bee communities in habitats of the Naban reserve of Xishuangbanna

by Douglas Chesters 1, Xiuwei Liu 2, Qingyan Dai 3, Zeqing Niu 4, Yuan Zeng 5, Konrad Martin 6, Chaodong Zhu7
1 Institute of Zoology, Beijing, China
2 Institute of Zoology, Beijing, China
3 Institute of Zoology, Beijing, China
4 Institute of Zoology, Beijing, China
5 Institute of Remote Sensing and Digital Earth, Beijing, China
6 University of Hohenheim, Stuttgart, Germany
7 Institute of Zoology, Beijing, China

Bees as pollinators are amongst the most important ecosystem service providers, but understanding plant-pollinating interactions and managing pollinator biodiversity loss is hindered by severe taxonomic impediments and paucity of publicly-available molecular data, particularly in the tropics. We apply integrative species delineation and taxonomy to test impacts of land use on diversity of bee communities within the Naban reserve of Xishuangbanna. Based on analysis of DNA and morphology of collected insects, totally 128 Operational Taxonomic Units (OTU) were inferred over all data. OTU richness and diversity was high in young rubber plantations, although the composition was less unique than other species-rich habitats (natural forest edge and river banks), and older plantations (>8 years) showed very low diversity under all measures. Community structures were similar between the natural forest interior and edge, although analysis indicated contrasting drivers of diversity, with strong phylogenetic clustering (suggesting conservation of functional traits) in the interior. The description of bee communities herein permits more informed choices in the land management with respect to ensuring continuation of essential pollination services by bees.


Ecological impacts of rubber plantation on ant fauna: a case study from monsoonal tropics of Xishuangbanna, Southwest China.

by Akihiro Nakamura 1, Mark Jun M. Alcantara 2, Jutamart Monkai 3, Tial C. Ling 4, He Xu 5, Shuyin Huang 6, Shrushti Modi7
1 Xishuangbanna Tropical Botanical Garden
2 Xishuangbanna Tropical Botanical Garden
3 Xishuangbanna Tropical Botanical Garden
4 Xishuangbanna Tropical Botanical Garden
5 Xishuangbanna Tropical Botanical Garden
6 Xishuangbanna Tropical Botanical Garden
7 Xishuangbanna Tropical Botanical Garden

Rubber plantation has now become one of the most dominant human-modified landscape features in northern Southeast Asia. Despite a large number of studies documenting ecological impacts of rubber plantation, most studies focus upon changes in diversity per se and little attention has been paid to traits and ecological functions. We compared species and functional group composition, body size and predation pressure (arboreal and ground strata) of ants among rainforest, limestone forest and rubber plantation at Xishuangbanna, monsoonal tropical region of southwest China. We hypothesized that ant assemblages and predation pressure in rubber plantation are similar to those within limestone forest where tree species richness and structural complexities are depauperate compared with those of rainforest. The results, however, showed that ant assemblages in rubber were very unique, consisting of competitively dominant Dolichoderinae species and species with significantly much larger body size than those occurring in rainforest and limestone forest. Predation pressure in rubber plantation was similar to rainforest, whereas lower predation pressure was found in limestone forest. Our results suggested that monoculture plantation alters not only species diversity, but also other aspects of ecological properties.


Rubber plantations and arthropod communities in Xishuangbanna; novel habitat or new threat

by Beng Kingsly Chuo 1, Mohammed Armani 2, Kyle W Tomlinson 3, Richard T Corlett 4, Alice C Hughes 5, Shen Xianhui 6, Ferry Slik 7, Yann Surget-Groba8
1 Xishuangbanna Tropical Botanical Gardens (XTBG), Chinese Academy of Sciences
2 XTBG
3 XTBG
4 XTBG
5 XTBG
6 XTBG
7 XTBG
8 UQO

Xishuangbanna lies on the northern edge of Southeast Asia, within the Indo-Burma biodiversity hotspot. Its status as a biodiversity hotspot is under threat from anthropogenic activities caused by forest conversion to agriculture, especially plantations of rubber (Hevea brasiliensis). We investigated the impacts of forest conversion to rubber on litter arthropod diversity and composition. We sampled litter arthropods from 17 paired forest-rubber sites using the Winkler extraction method. Arthropods were metabarcoded using a new primer combination and the Illumina Miseq platform. The resulting reads were quality filtered and clustered into 2,414 operational taxonomic units (OTUs) at ≥ 97% similarity using a validated bioinformatics protocol. The taxonomy of each OTU was predicted using two taxonomic assignment algorithms and these results were compared. Richness and assemblage composition differences between forests and rubber were analysed for all OTUs combined and for OTUs assigned to eight arthropod groups. Arthropod communities in forests and rubber were substantially different, suggesting that arthropods are very sensitive to land-use change. The effects of land-use change on arthropod diversity were mostly negative, but were also non-existent for some arthropod groups. Diversity was generally high in forests and lower in adjacent rubber plantations. However, species turnover for Hemiptera and Blattodea was higher in rubber than in forests. This might be due to differences in plantation age and management regimes. Our findings are consistent with reports that landscape modification has negative effects on biodiversity, and these effects vary across functional guilds. Substantial community differentiation between forests and rubber suggests that rubber plantations create novel habitats for distinct groups of arthropod species.


The Economics of Smallholder Rubber Farming in a Mountainous Region of Southwest China: Altitude, Ethnicity and Risk

by Herrman Waibel1
1 Leibniz Universität Hannover

Expansion of rubber cultivation in Southern China has remarkably contributed to the development of the rural economy but also has led to negative environmental consequences. While there is numerous anecdotic and some scientific evidence on theses aspects there is a lack of comprehensive and representative analysis of the profitability and the risks associated with small holder rubber cultivation in China . Using the data collected from a comprehensive household survey of 612 smallholder rubber farmers in Xishuangbanna Dai Autonomous Prefecture of southern Yunnan province, we quantify the economic and environmental consequences of smallholder rubber farming. In this paper we focus on land use, input-output, smallholders’ income composition and risks. Particularly, we compare the differences that exist among ethnicities and across different altitudes. Results suggest that natural rubber production is highly profitable, however subject to the price of rubber. Rubber monoculture is widespread and on average over 40% of household income is from rubber. This lack of diversification poses income risks and the declining rubber prices make rubber cultivation economically risky. Furthermore, rubber monoculture causes environmental risks which are increasingly recognized by farmers. Differences in economic and environmental aspects of farming among ethnicities and locations can be shown. The findings provide important quantitative information with regard to smallholder rubber farming for policy-makers, and show entry points for future research.


Greenhouse gas emissions in rubber plantations

by Stefanie Goldberg 1, Jutamart Monkai 2, Jianchu Xu 3, Rhett Harrison4
1 World Agroforestry Centre, East and Central Asia, Kunming, China
2 Centre for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Science, Kunming 650201, Yunnan, China
3 World Agroforestry Centre, East and Central Asia, Kunming, China
4 World Agroforestry Centre, East & Southern Africa Region, 13 Elm Road, Woodlands, Lusaka, Zambia

The expansion of rubber plantations causes various environmental problems, such as decrease of biodiversity, increased soil erosion, loss of soil C, and nitrate leaching into the groundwater. Regarding greenhouse gas emissions, rubber plantations have been considered as ecosystems of minor contribution. However, 1) missing long-term and geographically diverse studies don’t allow for upscaling existing results and 2) recent studies give hints that the greenhouse gas budget from rubber plantations could be much higher than expected. In this context, management practices play an important role in the environmental impact and the greenhouse gas budget of rubber plantations. In this talk, we will present the result of studies carried out in rubber plantations in Yunnan, China. In our first study, we compared soil respiration, CH4 and N2O emissions in traditionally managed rubber plantations (understorey is sprayed with herbicide twice per year to eliminate understorey regrowth) and tropical rain forest. In addition, we measured soil gas concentrations down to 70 cm to localize zones of production and consumption. As a next step, we examined and compared an alternative management practice, where the understorey was allowed to regrow. Together with greenhouse gas emissions, we analyzed microbial diversity, differences in hydrology and soil erosion. Our results highlights the need for 1) long-term measurements of greenhouse gas emissions under different environmentally sustainable rubber management practices; and 2) more “in-depths” investigations to understand greenhouse gas producing and consuming processes that occur belowground.


Heveadapt: How can Thai rubber smallholders face global challenges?

by Philippe Thaler 1, Bénédicte Chambon 2, Pierre-Marie Bosc 3, Eric Penot 4, Henri Robain 5, Frédéric Do 6, Frédéric Gay 7, Uraiwan Tongkaemkaew 8, Nopmanee Suvannang 9, Karn Trisophon 10, Kannika Sajjaphan 11, Poonpipope Kasemsap12
1 Cirad, UMR Eco&Sols, Hevea Research Platform in Partnership, Bangkok, Thailand
2 Cirad, UPR 34, Hevea Research Platform in Partnership, Bangkok, Thailand
3 Cirad, UMR MOISA, Montpellier, France
4 Cirad, UMR Innovation, Montpellier, France
5 IRD, UMR iEES Paris, Bondy, France
6 IRD, UMR Eco&Sols, Montpellier, France
7 Cirad, UMR Eco&Sols, Montpellier, France
8 Faculty of Technology and Community Development, Thaksin University, Phatthalung province, Thailand
9 Office of Science for Land Development, LDD, Bangkok, Thailand
10 Land Development Department, Regional Office 6, Chiang Mai, Thailand
11 Department of Soil Science, Faculty of Agriculture, kasetsart University, Bangkok, Thailand
12 Department of Horticulture, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand

Heveadapt is a multidisciplinary project on the sustainability of Thai rubber farms, mainly smallholders, facing global changes. Examples of the ongoing studies show how biophysical factors interact with socio-economic ones to determine the risks faced by farmers, and the possible coping strategies. The shortage of manpower and low rubber price could be answered by Low Intensity Tapping Systems (LITS) increasing the return to labour and by diversification, such as agroforestry. It is difficult to reduce tapping frequencies because farms are small and hired tappers are paid by crop-sharing. Contracts would have to be renegotiated and tappers work for several farmers. Moreover access to other sources of income could be limited. Permanent agroforestry systems (AFS) are present in southern Thailand, associating timber, fruit trees or vegetables to rubber. Despite their interest for income resilience when rubber price is low, they are not widespread. Manpower issues, access to market and to information seem determining. The higher biodiversity in AFS could also limit the overall decrease in soil quality that we showed after repeated rubber monoculture on the same land. Our first results based on soil functions (Biofunctool) showed that the understory coverage was the main factor to keep soil biodiversity and quality. However this coverage depended less on the system (AFS or monocrop) than on management practices. This may also explain the higher erosion under rubber than maize observed in Northern sloppy areas, as farmers tend to weed rubber inter-row intensively. Increasing rubber genetic diversity, better knowledge of resources use and adaptation to coming stressful climatic conditions are also key challenges for rubber clone selection. Our ongoing studies show large genetic variation in water use and adaptation to water constraints. The next phase of the project will be to synthesize these observations through integrated diagnosis, modelling and participative innovation platforms.


Farmers’ attitudes to promoting sustainable rubber cultivation: Evidence from Xishuangbanna, China

by Shaoze Jin 1, Shi Min 2, Hermann Waibel3
1 Leibniz Universität Hannover
2 Leibniz Universität Hannover
3 Leibniz Universität Hannover

In the last 30 years, Xishuangbanna (XSBN), one of the global hotspots of biodiversity protection in Southern China, has suffered a series environmental problems with the rapid expansion of rubber farming. A program named “Environmentally Friendly Rubber Plantation (EFRP)” has been proposed by the government and local researchers to mitigate the negative environmental effects of rubber cultivation and improve its sustainability. However, due to the lack of sufficient information, this program is still not widely accepted among the farmers. Based on the data which were collected in early 2013, we find that around 10% of the farmers are not aware of the negative effect of rubber cultivation on the environments. Nevertheless, the awareness of this problem could be a driving factor for the farmers to participate in ecosystem protection measures. In early 2015, we evaluated the farmers’ knowledge of e.g. the suitable growth conditions of rubber, including altitude, slope, cropping system, and planting place. In addition, we estimate the extent of and the factors effecting the farmers’ willingness to accept the recommendations from the EFRP using Tobit model. Our results show that only 11% of the farmers know the EFRP and 8% of them know the government promotes this program. Smallholders who are more aware of the importance of EFRP are more willing to participate and apply the knowledge into the practice. Moreover, their willingness to participate is also dependent on the socioeconomic characteristics of household, income sources, and the current situations of rubber plantations. Our findings bring great significance for the local agricultural extension service and the other agencies, and the consequent policy implications for promoting sustainable development of rubber farming in XSBN.


Assessment of Governance Mechanisms, Livelihood Outcomes and Incentive Instruments for Green Rubber in the Lao PDR and Myanmar

by Miles Kenney Lazar 1, Grace Wong 2, Aaron Russell 3, Himlal Baral4
1 Graduate School of Geography, Clark University
2 CIFOR
3 CIFOR
4 CIFOR

Over the past decade, rubber tree cultivation has expanded rapidly throughout the Mekong region, from established production centers in Thailand, China, and Vietnam to new sites in the Lao PDR, Myanmar, and Cambodia. Rubber has brought opportunities for development and increased incomes, but has also generated social and environmental challenges of impaired food security, land dispossession, and forest loss. Furthermore, the post-2012 precipitous drop in rubber prices has sent the sector into disarray, constraining farmers’ and companies’ ability to profit and challenging government discourses that frame commercial crops as a driver of development. In this paper, we examine how rubber production in the Lao PDR and Myanmar is governed, particularly the socio-ecological dynamics of varying cultivation models: smallholding, contract farming, and large-scale estate plantations. Based upon an analysis of secondary literature and interviews with key stakeholders, we found that rubber production is mostly not “green”, meaning that it has not alleviated poverty and maintained ecosystem services and forested areas. Most smallholders have not seen their incomes increase due to the current price drop and have variably left their trees untapped or abandoned, while wage labor opportunities on estate plantations are limited due to the limited profitability of production. Large-scale estates have been established on land expropriated from rural people and have replaced forested areas that provide ecosystem services to local communities. We argue that, of the three cultivation models, smallholding rubber has the greatest potential to achieve the goals of a “green” crop to support national development and poverty reduction goals. To do so, however, there must be significant policy changes made to production and trade, including guarantees of minimum price supports from the state, appropriate land use planning measures, the establishment of production and marketing cooperatives, the protection of community land rights, and the implementation of alternative agroforestry models.


Labor management in mature rubber plantation of farmers in Northeast Thailand

by Arunee Promkhambut1
1 Program on System Approaches in Agriculture, Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen Thailand.

Labor is importance for mature rubber plantation mainly for latex harvesting. Nevertheless, data from National Statistical Office shows the dramatically decline in number of young laborers in agricultural sector but 3 folds increase in aged labors since the past 2 decades. During the high price of rubber, remigrate of labors from the city to rubber farms has been noticed but with continuous declining of rubber price, no study has been done. How farmers in Northeast Thailand manage their labor used in their fields under the changes situation of labor and price of rubber is the main question in this study. Therefore, a survey research was conducted with 100 farmers in 2 provinces, representative of a the most and less dynamic of laborers used in rubber farms, to describe source of labor, activities of labor, labor productivity, and factors related with the sources of labor chosen by farmers. Impact of different sources of labor on tree performance and profitability will also be discussed.


Exploring Futures of Xishuangbanna: Livelihoods, wellbeing and adaptation

by Su Yufang 1, James Hammond 2, Xu Jianchu 3, Yi Zhangfang4
1 Center for Mountain Ecosystem Studies (CMES), Kunming Institute of Botany (KIB), CAS, Kunming, China
2 World Agroforestry Centre (ICRAF)
3 CMES, KIB, CAS, Kunming, China
4 World Agroforestry Centre (ICRAF)

Monoculture rubber plantations have expanded beyond the rubber growing-limit to very high elevations (occupying 22% of total land) in Xishuangbanna during the past 30 years. Local incomes come mainly from rubber revenue, placing the inhabitants in a vulnerable situation given the fluctuations of the natural rubber market. There is increasing concern on livelihood diversification and secured ecosystem services among different stakeholders. 1015 households survey has been conduced to understand local livelihood and its determinants, and their perception of future changes and response. The survey results show that more than 90% of households are engaged with either rubber (low and mid elevations) or tea (the high elevations). Intended livelihood change and adaptation responses are explained by diverse values and variables: a single solution does not exist. The mid altitudes are more likely to adapt compared to low and high altitudes. Policies can be designed and tailored to account for vulnerable segments of the community, likely adaptation responses and the factors of change.


Overview and Major Constraints of Natural Rubber Industry in Myanmar

by Zar Ni Zaw1
1 Myanmar Rubber Planters and Producers Association

Myanmar is one of rubber producing countries and contributed around 1.5 percent of the world rubber production in 2015. Since the last two decades, the country’s natural rubber industry has developed and rubber planting area has been expanded rapidly especially in 2007. Consequently, productive area has been increasing apparently and also the production is expected to be substantial within these years. Although the planted area, the productive area, and the production have increased respectively, there are two major weaknesses – low productivity and inferior quality which retard the development of the industry. The major causes of the low productivity in Myanmar are still planting seedlings and unproven or uncertain cultivars, lack of any support and regulation from the government, limitation of tapping days due to high rainfall in major rubber growing area, implementing high frequency tapping system, no adoption of improved tapping systems and lack of systematic tapping panel management. The product sharing payment system also creates low productivity and high production cost. The major causes of the inferior quality are lack of education to planters and processors to produce high quality rubber, lack of any control and related regulation for the production, processing, trading and export of rubber in accordance to the types of specification along the whole supply chain, lack of certification system for the quality of export rubber and lack of quality control laboratory at most TSR factories to specify their produced rubber accordingly. The downstream product manufacturing sector is also not yet developed. Thus, it needs to resolve these constraints for the industry to be competitive and long sustainability.


Three main nutrients removal content in rubber yield for optimal fertilizer supply guideline

by Supat Isarangkool Na Ayutthaya 1, Sophea Nhean 2, Siwaporn Siltecho 3, Sayan Sdoodee4
1 Horticultural section, Faculty of Agriculture, Khon Kaen University, Thailand and Knowledge Development for Rubber Tree in Northeast, Khon Kaen University
2 Rubber Development Department, General Directorate Of Rubber, Ministry of Agriculture, Forestry and Fisheries, Phnom Penh, Cambodia
3 Land Development Department, Ministry of Agriculture and Coorperatives, Thailand
4 Department of Plant Science, Faculty of Natural Resources, Prince of Songkla University, Hat Yai, Songkhla, Thailand

Nowadays, the recommendations of fertilizer are still not specific to plant requirement. One technique is in a developing process which is the giving of fertilizer by compensation of nutrients loss by crop removal. Therefore, this study was to evaluate the amount of nitrogen, phosphorus and potassium in the rubber yield. The experiment was done in the rubber clone RRIM600 and RRIM251. The age of rubber clone RRIM600 was 9 years old (third year tapping), while the rubber clone RRIT251 was 8 years old (second year tapping). All plantations were in the dry area with <1,200 mm of annual rainfall located in Kaen Dong district, Buriram province. The sampled trees for later yield investigation were 60 trees in each clone. The latex was weighted in each tapping day during June 2015-January 2016. Also, the latex yield was collecting for nitrogen (N), phosphorus (P) and potassium (K) analysis in 3 periods: end June, end August and early November 2015. The result showed that the pattern of latex production of RRIM600 increased 1.5-2 times in the weight of latex in 2-3 months at end of yearly tapping, while RRIT251 had slightly increasing of latex at the end of yearly tapping. The total dry yield of RRIM600 and RRIT251 clones were 4.8 kg tree-1 and 2.54 kg tree-1. The N in dry rubber of RRIM600 clone was highest in November, but there was not significant difference in RRIT251 clone. The P in dry rubber had no differed with periods, while the potassium content showed the highest value in November. The nutrient removal calculations of N, P and K for RRIM600 were 15.7 g tree-1, 8.5 g tree-1 and 20.6 g tree-1, respectively, while the yield of RRIT251 removed 7.42 g tree-1 for N, 2.15 g tree-1 for P and 10.26 g tree-1 for K.


Soil gaseous carbon flux in rainforest and rubber plantations

by Rong Lang 1, Sergey Blagodatsky 2, Stefanie Goldberg 3, Jianchu Xu 4, Georg Cadisch5
1 Institute of Agricultural Sciences in the Tropics, University of Hohenheim; Center for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Sciences.
2 Institute of Agricultural Sciences in the Tropics, University of Hohenheim
3 World Agroforestry Centre, East and Central Asia
4 World Agroforestry Centre, East and Central Asia
5 Institute of Agricultural Sciences in the Tropics, University of Hohenheim

The impact of rubber expansion on greenhouse gas fluxes from soil has been insufficiently studied, especially lacking the understanding of changes in underlying soil processes. Aimed to understand how land use change affects the soil CO₂ and CH₄ fluxes, we measured surface gas fluxes, gas concentration gradient, and ¹³C signature in CH₄ and soil organic matter in profiles in a transect in Xishuangbanna, including a rainforest site and three rubber plantation sites with age gradient. Gas fluxes were measured by static chamber method and open chamber respiration system. Soil gases were sampled from installed gas samplers at 5, 10, 30, and 75cm depth at representative time in dry and rainy season. The soil CO₂ flux was comparable in rainforest and old rubber plantations, while young rubber plantation had the lowest rate. All sites were CH₄ sinks in dry season and consumption decreased in the order of rainforest, old rubber plantations and young rubber plantation. From dry season to rainy season, CH₄ concentration increased in all depth with higher increment in older rubber plantations; CH₄ flux shifted to weaker consumption in rainforest and young rubber plantation, or even towards to emission in older rubber plantations; enrichment by ¹³CH₄became less or occasionally depleted. δ¹³C in soil organic matter and soil moisture increased from rainforest, young rubber plantation to old rubber plantations. The upper 30cm soil was major responsible for CH₄ consumption. Conversion the forest into rubber plantation decreased soil respiration in young plantation and it recovered during rubber development. However, CH₄consumption by soil was weakened in plantations of all ages. Seasonal change of CH₄ flux and ¹³CH₄ enrichment was larger under rainforest than rubber plantations, indicating modified soil water regime under rubber. Converting forest into rubber plantations may have profound impact on soil function as CH₄ sink.


Seasonal occurrence of pesticides in a watershed of Xishuangbanna, Yunnan, China

by Neda Azizi 1, B. Kuch 2, M. Krauss 3, H. Steinmetz4
1 University of Stuttgart
2 University of Stuttgart
3 University of Stuttgart
4 University of Kaiserslautern

Nowadays China is one of the largest producers and consumers of pesticides in the world. Due to the widespread and intensive use of pesticides and increasing water scarcity the impairment of water quality is of growing concern. Investigations of pesticide levels in Chinese environment mainly focus on densely populated and economically developed coastal regions and large water courses. The knowledge on the occurrence and fate of pesticides in Chinese remote regions and small river catchments is still low (Grung et al. 2015). Monitoring programs primarily determine representatives of the group of organochlorine pesticides (OCPs) such as DDT and HCH, which are regulated by law in China since 1982 (Wang et al. 2005). Only few data on currently used pesticides are known. In contrast to the OCPs, these substances are characterized by different physico-chemical properties (e.g. sorption tendency, transport behavior, bioaccumulation, water solubility and degradability). Accordingly, effects on environmental compartments (e.g. drinking water resources) manifest in a different way. This study focused on a preliminary pesticide inventory of the Naban river catchment on the basis of a non target screening. The tributary of the Mekong river is located in Jinghong County, Dai Autonomous Prefecture Xishuabanna of Yunnan Province (South China). As a result of this study currently used pesticides (e.g. atrazine and the degradation product desethylatrazine) were identified in the surface water in variable concentration levels and with shifting substance pattern. The results indicate the pronounced seasonal occurrence of these pesticides and the highly dynamic effects, which are caused by the individual structure of the small catchment and the local variety of land use.


Exploring the deep frontier: rooting patterns of rubber trees in Southeast Asia

by Jean-Luc Maeght 1, I. Saban 2, D. Arifiyanto 3, C. Clement 4, S. Gonkhamdee 5, S. Sdoodee 6, A. Pierret7
1 IRD/ALUPC UMR 242 iEES-PARIS & SFRI Hanoi Vietnam
2 SOCFIN Indonesia, Medan, Sumatra, (Indonesia)
3 SOCFIN Indonesia, Medan, Sumatra, (Indonesia)
4 IWMI, Vientiane Lao PDR
5 Faculty of Agriculture, Khon Kaen University, Khon Kaen (Thailand)
6 Prince of Songkhla University, Hat Yai (Thailand)
7 IRD/ALUPC, UMR 242 iEES-PARIS, Ban Nongviengkham, Vientiane (Laos)

While research on deep roots is still in its infancy compared to that on shallow roots, published papers tend to show that deep roots are common in a wide range of plant species. In addition, deep roots appear to be of pivotal importance for plant functioning, subterranean biocenosis and many biogeochemical cycles and ecosystem services such as, soil carbon sequestration and moisture regulation in the lower troposphere. We investigated the deep rooting patterns of rubber trees (Hevea brasiliensis Muell.-Arg.) at three Southeast Asian locations, namely Northeast Thailand, Southern Thailand and North Sumatra. These locations encompass a wide range of climatic and soil conditions and mean annual rainfalls of less than 1,200 to more than 2,200 mm. We consistently observed fine roots at soil depths of at least 2-3 m; this result indicates that, in rubber tree, deep rooting patterns are likely to be primarily related to a genetic determinism, even though environmental factors may modulate such determinism. At all locations, fine root biomass standing below 1 m amounted to between 30 and 50% of the total fine root biomass, which is of the same order of magnitude as the biomass of coarse woody roots. At the Northeast Thailand site, we characterized root dynamics. Deep fine roots (2m) appeared to be less responsive to rainfall compared to shallow roots. We also observed deep emergence root during the dry season. Rubber trees have deep roots, which extend far beyond the first meter of soil, regardless of climate and/or edaphic conditions. Further studies are needed to clarify the functional role of these deep roots. They play a role in the extraction of mobile nutrients and of deep water resources. Deep root system of rubber trees would therefore represent a “safety net” to cope with pedo-climatic variability. This result has important implications for the selection of new genetic material.


Comparison of transpiration characteristics in different aged rubber plantations

by Youxing Lin 1, Yiping Zhang 2, Xiang Zhang 3, Xuehai Fei 4, Jing Li5
1 Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences
2 Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences
3 Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences
4 Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences
5 Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences

Sap flow density of rubber trees (Hevea brasiliensis) of four ages (13 years old, young; 25 years old, middle-aged; 33 years old, middle-old-aged; and 50 years old, over-mature) in Xishuangbanna of Southwest China was measured by the Granier thermal diffusion probe technique from January 2013 to December 2014, and then scaled up to estimate stand-level transpiration. The results showed that, on day, month, season and year time-scales, the middle-aged trees had the highest mean sap flow density, being significantly higher than the other aged trees ( P<0.01). The over-mature stands had the highest annual transpiration rate ( 1212.49±42.80 mm per year), being significantly higher than those of the young and middle aged stands ( P<0.01). With the increase of stand age, the sap flow density of rubber trees generally followed a parabola change, with the peak in the most vigorous middle-aged stand. The transpiration of rubber stands increased with increasing stand age in general, and the over-mature stand had the highest transpiration. The mean annual sap flow density of rubber stands in Xishuangbanna was estimated as 16.42±3.24 g·m-2·s-1 and the mean annual transpiration as 870.58±145.89 mm.


Nitrogen fertilization effect on N2O emissions from a typical rubber plantation

by Wen-Jun Zhou 1, Yi-Ping Zhang 2, Jing Zhu3
1 Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences
2 Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences
3 University of Chinese Academy Sciences

Transformation of primary tropical rainforests to rubber plantations has been widely occurring in Southwest China and Southeast Asia. Effects of fertilization on nitrous oxide emission are not very clear yet and N2O emission factors of fertilizer nitrogen applied to rubber plantations are still waiting for experimental quantification. To meet this requirement, we carried out 2-year field measurements of N2O fluxes from fertilized and unfertilized fields of a typical rubber plantation in Xishuangbanna. Our results show that the N2O emission from the fertilized and unfertilized fields on average at 3.96 and 2.50 kg N ha–1 yr–1, respectively. Accordingly, the direct N2O emission factor was determined as 1.96%. The N2O emissions of all the treatment were higher in the rainy season and lower in the dry season which agree with the temperature and soil moisture dynamics.Besides soil water content and soil temperature, area weighted mean NH4+-N content was the domainted the temporal distribution of the area-weighted mean N2O flux of the fertilized and unfertilized rubber plantation. Although NH4+-N was not the main influence on temporal changes in N2O emissions from the trench, slope, or terrace, but was the main control on spatial variations between the treatments. At a unit area, the 100-year carbon dioxide equivalence of the N2O released from the typical fertilized rubber plantation can offset approximately 6% of the carbon sink occurring in this ecosystem or 20% of the carbon sink occurring in the local primary rainforest. Simply upscaling these results to entire Xishuangbanna region according the land areas, N2O emission from fertilized rubber plantations may offset about 17% of the carbon sink of the primary tropical rainforests. Our study implicates that changing tropical rainforests to fertilized rubber plantations may intensify climate warming by enhancing the regional N2O emission that offsets the carbon sink potential of the tropic forests.


Field comparison of water use in 5 immature rubber clones

by N. Puangjumpa 1, S. Isarangkool Na Ayutthaya 2, S. Nhean 3, R. Rungtawan 4, D. Chura 5, D. Srisondee 6, J. Phattaralerphong 7, R. Rattanawong 8, A. Rocheteau 9, F.C. Do10
1 Horticultural Section, Faculty of Agriculture, Khon Kean University, Khon Kean 40002
2 Horticultural Section, Faculty of Agriculture, Khon Kean University, Khon Kean 40002
3 Horticultural Section, Faculty of Agriculture, Khon Kean University, Khon Kean 40002
4 Faculty of Agriculture, DORAS Centre, Kasetsart University 10900 Bangkok
5 Faculty of Agriculture, DORAS Centre, Kasetsart University 10900 Bangkok
6 Department of Agriculture and Resources, Faculty of Natural Resources and Agro-industry, Kasetsart University
7 Department of Agriculture and Resources, Faculty of Natural Resources and Agro-industry, Kasetsart University
8 Nong Khai Rubber Research Center, Rubber Authority of Thailand
9 IRD, UMR Eco & Sols, Campus Sup Agro-INRA, F-34060 Montpellier, France
10 IRD, UMR Eco & Sols, Campus Sup Agro-INRA, F-34060 Montpellier, France

The objective was to evaluate the water use and clonal diversity between 5 immature rubber clones including the main clone planted in Thailand. The study was conducted in well-watered conditions at the end of the rainy season between September and October 2015 at Nong Khai Rubber Research Center, in northeast Thailand. The measurements were made on 3 year old of rubber clones: RRIM 600, RRIT 408, RRIT 251, BPM 24 and PB 260. The experimental design included 3 randomized blocks with four trees per clone inside each. The water use was estimated by multiplying xylem sap flow density by sapwood area. Sap flow density was recorded over 34 days by the transient thermal dissipation method with a single probe inserted 60 cm high above soil level. Repeated measures ANCOVA was performed according 3 factors (clone, block, tree) and the daily cumulative solar radiation as co-variable. The water use was about 10 L d-1 with 40 % variation between extreme clones from 12.5 L d-1 (0.8 mm d-1 for RRIM 600 to 9.4 L d-1 for BPM 24. The interaction between clones and solar radiation was significant but not the clone effect alone due to large tree to tree variation. Highly significant difference in sapwood area mainly explained the previous clonal variation. The sapwood area decreased by 74 % from 0.467 dm-2 for RRIM 600 to 0.27 for PB260. The daily sap flux density showed a negative relationship with sapwood area between clones. The values increased by 15 % from 27.8 L dm-2 d-1 for RRIM 600 to 32.0 L dm-2 for PB 260. Ours results provide new insights on water use of immature rubber clones. They stress up the importance of research and choice on rubber plant material.


Bird Monitoring for Green Rubber

by Francis Commercon1
1 Colorado State University

The large-scale conversion of natural lowland tropical rainforests in SE Asia to monoculture rubber plantations has resulted in tremendous losses in avian diversity across large tracts of land. I initiated bird monitoring in the rubber plantations around Man’e village in Xishuangbanna prefecture, southwest China, as part of a larger sustainable rubber experiment by the World Agroforestry Center. Named Green Rubber, this experiment interplants multiple crops in the understory of smallholder farmers’ lands to explore the impacts of various complexities of intercropping on both economic and environmental variables. Green Rubber stems from the expectation that more complex agricultural systems yield not only greater income security for farmers but also higher levels of plant and animal diversity. Birds are the largest and most wide-ranging taxa considered in biodiversity monitoring under Green Rubber. The objective of bird monitoring is to determine whether intercropping improves bird density and diversity at the landscape level. In June 2016, before planting of intercropped species had begun, I used standardized point counting techniques to complete an exhaustive survey of birds in the intended treatment plots. This established baseline data for later comparison. I also established clusters of control plots for each treatment cluster, carefully selecting sites based on several factors affecting bird communities. The monitoring design allows for comparisons between a given year and the baseline data as well as comparisons between intercropped areas and non-intercropped areas within a given year.


Distribution of aggregate size fraction and associated soil organic carbon in rubber–based agroforestry systems: implication for land use

by ChenChunfeng1
1 Xishuangbanna tropical botanical garden, Chinese academy of sciences

Rubber-based agroforestry (Hevea brasiliensis) systems are considered to be the best way to improve soil properties and overall environmental quality of rubber monoculture, but few reports have examined soil aggregate stability in such systems. The objective of this study was to examine management and landscape effects on water stable soil aggregates (WSA), soil aggregate-associate carbon, nitrogen content and soil carbon, nitrogen accumulation in Xishuangbanna, southwestern, China. Treatments were rubber monoculture (Rm) and four agroforestry systems: H. brasiliensis–C. arabica (CAAs), H. brasiliensis–T. cacao (TCAs), H. brasiliensis–F. macrophylla (FMAs) and H. brasiliensis–D. cochinchinensis (DCAs). The WSA was determined by wet sieving method while the total organic carbon (TOC) and total nitrogen (TN) concentrations of bulk soil samples and the water-stable aggregate fractions were directly measured by dry combustion method. Three soil depths (0–5, 5–15 and 15–30 cm) were analyzed for all treatments. The results shown that rubber-based agroforestry treatments (except for CAAs) significantly increased total SOC and N and enhanced the formation of macroaggregates compared to Rm treatment. TOC and N in all water-stable aggregate fractions were significantly higher in rubber-based agroforestry systems (except CAAs) than in rubber monoculture. The macroaggregate fraction contained more organic carbon than the microaggregate fraction. The proportions of C and N loss from sieving and erosion were showed significantly negative correlation with C and N contractions in bulk soil. Surface cover with constant leaf litter fall and extensive root system in rubber-based agroforestry systems increased soil organic carbon and nitrogen, helped in better soil aggregation, reduced soil erosion and carbon and nitrogen loss and ultimately, improved the carbon and nitrogen accumulation rates.


Soil Water Repellency in Different Types of Rubber-Based Agroforestry Ecosystems in Xishuangbanna

by Zhu Kai1
1 XTBG of CAS

Water Drop Penetration Time and Water Repellency Index were used to determine the soil water repellency and soil physicochemical properties which were to be tested in four rubber-based (Hevea brasiliensis) agroforestry ecosystems with different interplants (Camellia sinensis, Theobroma cacao, Flemingia macrophylla, and Dracaena americana) and rubber monoculture in Xishuangbanna, southwest China. The relationship between soil properties and soil water repellency was determined by using Pearson correlation analysis and Stepwise regression analysis. The results showed that when compared with agroforestry ecosystems, both the persistent of soil water repellency time and the Index of soil water repellency in rubber monoculture were significantly higher. Different land use patterns have certain influence on the hydraulic characteristics of the soil, except Flemingia macrophylla, hydraulic conductivity in rubber monoculture was significantly lower than rubber-based agroforestry ecosystems. The Pearson correlation analysis showed that a significant negative relation between soil water repellency and soil hydraulic conductivity. Stepwise regression analysis showed that the soil bulk density and soil texture were the most significant factors in soil water repellency of rubber-based agroforestry ecosystems. In conclusion, building agroforestry ecosystems instead of rubber monoculture can effectively reduce soil water repellency and increase soil water infiltration, and ultimately control soil erosion.


Farm Types and Farmer Motivations to Adapt: Implications for Design of Sustainable Agricultural Interventions using the Example of Rubber Plantations in South West China

by James Hammond1
1 ICRAF

Tropical land use is one of the globally leading causes of environmental change, and the tropical regions are also often impoverished. Sustainable agricultural development aims to reduce the negative environmental impacts of tropical land use whilst enhancing the well-being of the small holders and rural poor residing in those areas. Interventions with this goal are typically designed by scientists educated in the Western tradition, and often achieve lower than desired uptake by small holder farmers, the potential users of these interventions. We build on work done in farm type classification and studies of factors that influence adoption, trialling a suite of household survey questions to elucidate directly the factors that influence a farmer’s motivations to adapt the farming and livelihood practices. Based on a sample of 1,000 households in the rubber growing region of Xishuangbanna, South-west China, we found that farm types could not be used to accurately predict farmers’ motivations to adapt. Clusters of motivational groups were distributed across all six farm types identified. In order of most to least likely to adapt, the motivational clusters were called Aspirational Innovators, Conscientious, Copy Cats, Incentive-centric, Well Settled, and Change Resistant. These groups roughly corresponded with those identified first in marketing studies and literature regarding diffusion of innovations, but such classifications are rarely used in development literature. We found that only one third of the population would be potentially willing to trial a new intervention, and recommend that those sectors of the population should be identified and preferentially targeted by development programs. Such an approach would require dedicated data gathering beyond what is usually carried out for ex-ante farm typologies, but with some refinements the process need not be onerous.


Community structure of soil mesofauna in different stages of rubber plantation

by Fan Chen 1, Huiping Zhou 2, Yaohua Tian3
1 Yunnan Institute of Tropical Crops
2 Yunnan Institute of Tropical Crops
3 Yunnan Institute of Tropical Crops

The affection of rubber plantation to soil mesofauna is still scarcely reported. We investigated the community structure of soil mesofauna at 3 stags of rubber plantation and 2 tea and macadamia plantations in dry and rainy season. The individual density of soil mesofauna was higher; meanwhile Shannon diversity index was lower in rainy season than in dry season at all of the 5 plantations. There was a tendency of lower individual density at 3, 10, and 30 years rubber plantation in dry season, whereas in rainy season, 10 years rubber plantation has a lowest individual density of soil mesofauna. There were no significantly differences of individual density and diversity index among rubber, tea, and macadamia plantations in dry and rainy season. The results suggest that rubber plantation couldn’t influence soil mesofauna biodiversity more than other economic crops.


Natural Rubber Research in Colombia: advances in process standarization in Bajo Cauca Antioqueño

by Jaime Escobar 1, Carlos Rodriguez 2, Maria Camila Herrera3
1 EAFIT University
2 EAFIT University
3 EAFIT University

Colombia has suffer problems with illicit crops (such cannabis or coca), but twenty years ago the government started a strategy to give different options to the farms in order to reduce the quantity of the ilicit plantation. That is how rubber became an important crop. Even though, it was intended for the farmers growth, there are some difficulties that need to be solved. Some of them require technical research such as: clon studies, material caracterization, plants nutrition, process standardization, lean farm and procces and products design. Others require the social and the environmental studies. This work is centered in the research and advances made in the lean manufaturing and process standarization. However, those matters cannot be concibed without education, co-working with the farmers and a research of their culture and the environment. The research was applied in several small-scale farms placed in Bajo Cauca Antioqueño region, at Antioquia, Colombia. Several tools of lean farm and process standarization were used, as standard operation condition, job standarization work, standard operation sheets among others. All of them were delivered to the community through educational programs and were co-builded with them. The coworking between researchers and farmers throw results that helped to improve the quality of the rubber products and processes.


Soil chemical properties and leaf nutrient contents in chronosequence of the rubber plantation in NE of Thailand

by Parintorn Boonkua 1, Vidhaya Trelo-ges 2, Chutinan Choosai 3, Nopmanee Suvannang 4, Siwaporn Siltecho 5, Claude Hamecker 6, Nitjaporn Koonklang 7, Supat Isarangkool Na Ayutthaya8
1 Land Resources and Environment section, Faculty of Agriculture, and Knowledge Development for Rubber Tree in Northeast, Khon Kaen University
2 Land Resources and Environment section, Faculty of Agriculture, Khon Kaen University
3 Entomology section, Faculty of Agriculture, Khon Kaen University
4 Land Development Department, Ministry of Agriculture and Coorperatives, Thailand
5 Land Development Department, Ministry of Agriculture and Coorperatives, Thailand
6 Institut de Recherche pour le Développement (IRD), UMR 210, place Viala, Montpellier, France
7 Institut de Recherche pour le Développement (IRD), Khon Kaen
8 Horticultural section, Faculty of Agriculture, Khon Kaen University and Knowledge Development for Rubber Tree in Northeast, Khon Kaen University

Rubber tree (Hevea brasiliensis) is a major importance economic crop in Thailand as it represents a substantial source of income for small holders. Increasing demand of rubber production, the rubber tree was expanding to the marginal area in northeast (NE) of Thailand which was sandy texture, low soil fertility and nutrient leaching which often resulting in low yield of production. The study of soil chemical properties and leaf nutrient contents in chronosequence of the rubber plantation in NE of Thailand are needed in order to efficient management of farmer’s fields. And increase rubber’s yield. In this study, a chronosequence of 5, 11 and 22 years old plantations were monitored with 3 replications in each age. The experimental design was randomized completely block design (RCBD). The experiment was located at Kranuan District, KhonKaen Province. Each soil sample was described in the field sampled for 2 depths to represent the average rooting depth of rubber (0-15 and 15-30 cm). For leaf sampling, the leaves were collected from 4-5 branches per tree. Then, soil and leaf samples were analyzed for basic soil and plant chemical properties. The results showed that there were significant differences for nitrogen, organic matter and potassium in rubber aged 22 compare to the other ages. The older age seem to provide more nitrogen, organic matter and potassium compare to the young rubber, However, no significant impact of the age of the plantations on other soil chemical properties (pH, EC, P, Ca, and Mg) was found. For rubber leaf nutrient, the nitrogen, potassium and calcium in (22 years) rubber tree plantation had higher content than others.


Measuring Leaf Area Index in Asian Rubber Plantations – A Challenge

by Marc Cotter1
1 University of Hohenheim

In order to estimate water use and water requirements of tropical plantations systems such as rubber it is adamant to have accurate information on leaf area development of the plantation as the main determinant of evapotranspiration. Literature commonly suggests a number of different methods on how to obtain leaf area index (LAI) information from rubber plantations. Methods include destructive measurements of leaf area at peak LAI, indirect methods such as gap fraction methods (i.e. Hemiview and LAI 2000) and radiation interception methods (i.e. SunScan) or litter fall traps. Published values for peak LAI in rubber plantation differ widely and show no clear trend to be explained by management practices or the influence of local climate patterns. This study compares four methods for determining LAI of rubber plantations of different ages in Xishuangbanna, Yunnan, PR China. We have tested indirect measurement techniques such as light absorbtion and gap fraction measurements and hemispherical image analysis against litterfall data in order to obtain insights into the reliabiliy of these measuring techniques for the use in rubber plantation systems. In addition, we have tested the applicability of available satellite based remote sensing data. The results that we are going to present here clearly show that there is no consistent agreement between the different measurements. Site, time of the day, age of the trees and incoming radiation all had a significant effect on the results depending on the device or the method. This renders the data published so far doubtful as to their accuracy and their usefulness in estimating evapotranspiration from rubber plantations and the induced environmental effects.


Ecosystem services and biodiversity of rubber plantations – a systematic review

by Inga Haeuser 1, Kevin Thellmann 2, Marc Cotter 3, Joachim Sauerborn4
1 University of Hohenheim
2 University of Hohenheim
3 University of Hohenheim
4 University of Hohenheim

Humans benefit from ecosystems which provide free goods and services. The capacity of ecosystems to deliver such services is under constant stress since humans continue to alter the environment. Ecosystem service (ESS) approaches have the potential to pinpoint multiple benefits that humans derive from nature, including services without direct market value such as climate regulation, pollination and flood protection. Payments for Ecosystem Services (PES) schemes and land-use planning are two main fields of application that require reliable data about key ESSs provided by a given landscape. This review focuses on ESS studies on rubber (Hevea brasiliensis) cultivation and investigates whether the studies fulfil the mentioned requirements. We analysed 76 studies in respect to the regional origin, number of assessed ESSs by each study, distribution of ESSs concerning provisioning, regulating and maintenance, and cultural ESSs, and if the studies also included biodiversity. We found that there is still a huge gap between what topics scientists research (single or few ESSs that are easy to measure) and what information policymakers would need (results including multiple ESSs, ideally from different sections, which include less tangible ESSs such as cultural services). Of the analysed 76 publications only two fulfilled the requirements to inform policymakers, and even they were not truly interdisciplinary. The main challenge remains to develop interdisciplinary studies which require joint research or collaborative projects with sufficient funding to fulfil the required task.


Nutrient losses by erosion in upland immature Para rubber plantation of Northern Thailand

by Wanwisa Pansak 1, Jaruntorn Boonyanuphap 2, Natta Takrattanasaran3
1 Department of Agricultural Science, Faculty of Agricultural Natural Resources and Environment, Naresuan University, Phitsanulok Thailand 65000
2 Department of Natural Resources and Environment, Faculty of Agricultural Natural Resources and Environment, Naresuan University, Phitsanulok Thailand 65000
3 Land Development Department, Ministry of Agriculture and Cooperatives, Thailand 65000

In Northern Thailand, some original forests have been cleared for rubber tree cultivation. Intensive Para rubber plantation in upland areas is susceptible to soil erosion. The objectives of this study were (i) to assess erosion and soil nutrient losses in upland rubber plantation and (ii) to assess the net present value (NPV) of soil nutrient losses by erosion. Data were collected from farmer trials from 2014 -2015 at Muab sub-basin of the Nan watershed, with slope gradients ranging from 25 to >35%. Five treatments consisted of 1) maize, 2) 3-year-old rubber plus bench terrace, 3) 3-year-old rubber, 4) 1-year-old rubber intercropping with maize and 5) 1-year-old rubber. Erosion was measured by Gerlach troughs with tipping buckets installed at the upper, middle and lower slopes of each plot. The total annual rainfall at the experimental site was 1,330 mm. The soil was classified as a fine, mixed, active, isohyperthermic Typic Haplustalfs. The topsoil had a pH of 4.5, organic matter of 0.3-1.8%, P (Bray II) content of 2.8-7.0 mg.kg⁻¹ and K content of 99-149 mg.kg⁻¹. The result showed significant differences in soil losses among treatments. The lowest soil loss was observed with the treatment 4: rubber plus maize (5.08 t.ha⁻¹.yr⁻¹). Runoff was highest in the 3-year-old rubber (31.98 % of total rainfall). Total N, P and K losses by soil loss did not significantly different among treatments. The amount of nutrient losses by runoff including total N (1.52 – 3.41 kg.ha⁻¹), P (3.45 – 9.11 kg.ha⁻¹) and K (0.73 – 1.25 kg.ha⁻¹) were not statistically significant. The calculated NPV for 20 years showed that rubber intercropping with maize treatment had the highest value (2,277 Euro.ha⁻¹). Therefore, immature rubber intercropping with maize is suitable systems which can reduce erosion and also the losses of nutrients by erosion in the upland rubber plantation.


Can soil erosion be reduced by allowing understory vegetation in rubber plantations?

by Viktor Josefsson1
1 Kunming Institute of Botany

Rubber plantations cover around one fifth of Xishuangbanna and are one of the most common land use types in the region. Many rubber plantations are situated on slopes, which means that the potental for soil erosion is high. It is therefore important to study the effects of the plantations on erosion, and this importance is enhanced by the fact that rubber plantations are relatively new to the region, and their long-term effects on factors such as soil erosion might not yet be seen in the landscape. Monoculture rubber plantations have been shown to lose a much larger amount of soil and nutrients due to erosion than natural forests. However, exchanging rubber plantations with forests is in many cases not an option, but improved management of the understory in plantations might be. In this study, two practices were applied to rubber plantations in Nabanhe National Nature Reserve, Xishuangbanna: Current practice (CP), where the understory is sprayed with herbicice twice a year, and understory restoration (UR), where vegetation between the rubber rows is allowed to regrow. We measured the amount of soil and water trapped in overland flow collectors after a rain, and data collection was carried out throughout the rainy season. The results show that 6-8 times more soil was lost in CP compared to UR. The CP areas also had a 9-19 % larger volume of overland water flow than the UR. As this paper presents the data from just the first rainy season after treatments were implemented, hence these differences are likely to increase as the vegetation in the UR continues to grow. These results indicate that a change in</span> management of rubber plantations could drastically reduce soil erosion and might also mitigate against flooding during the rainy season.


Analysis on Annual Diameter Growth Patterns of Rubber Tree Variety in Hainan Island,China

by Dongling Qi 1, Guishui Xie 2, Zhixiang Wu3
1 Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences / Danzhou Investigation and Experiment Station of Tropical Crops, Ministry of Agriculture, Danzhou , China
2 Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences / Danzhou Investigation and Experiment Station of Tropical Crops, Ministry of Agriculture, Danzhou , China
3 Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences / Danzhou Investigation and Experiment Station of Tropical Crops, Ministry of Agriculture, Danzhou , China

Stem diameter seasonal growth rhythm and grey correlation of timber/latex variety Reken 628 of was discussed to provide references for scientific development of cultivation and management technology strategy of timber/latex variety. The stem diameter of from 5-7 years ages timber/latex variety Reken 628 was studied based on periodic and pointing observation method. Stem diameter growth process of timber/latex Variety Reken 628 was fit and analyzed using different theory growth equations of Logistic,Gompertz, Weibull,JonsonSchumacher,MorganMercerFlorin,Richards, Bertanlanffy, Exponential curve and Modified exponential curve and optimum growth equation theory was selected. The results showed that the stem diameter growth increment displayed a distinct alternation of “slow-fast-slow” rhythm. In which equations,Logistic between fitted value and actual value deviated significantly and the indices of fitness (R² of other theory growth equations were above 0.7000. Modified exponential curve was optimal fitting results. The growth course of the stem diameter might be partitioned into three periods of time by the sequential clustering analysis, namely early-slow-growth (January to May ),fast-growth (June to October),and late-slow-growth (November to December). Summer and autumn were the major fast-growing period. The stem diameter growth of Reken628 for the whole year does not stop period. the scientific strategies of cultivation and management techniques can be developed combined with diameter growth rhythm,and farming tending field activities are reasonable arrangements, then which can enable fast-growing high yield of timber/latex variety.


Spatial and seasonal variation in soil respiration along a topographical gradient in rubber plantations and natural forest in Xishuangbanna, SW China

by Yongli Zhao1, Stefanie Daniela Goldberg 2, Rhett D Harrison 3, Jianchu Xu4
1 Center for Mountain Ecosystem Studies,Kunming Institute of Bontany,Chinese Academy of Sciences,132 Lanhei Road,Kunming China
2 Center for Mountain Ecosystem Studies,Kunming Institute of Bontany,Chinese Academy of Sciences,132 Lanhei Road,Kunming China
3 World Agroforestry Centre, East & Southern Africa Region,
4 Center for Mountain Ecosystem Studies,Kunming Institute of Bontany,Chinese Academy of Sciences,132 Lanhei Road,Kunming China

Soil respiration is a key component of the global carbon cycle, and even small changes in soil respiration rates can result in significant changes in atmospheric CO₂levels. Hence, understanding soil respiration is vital to carbon budget calculations. This study focused on the spatial variability of soil respiration with respect slope position along two transects in natural tropical rainforest (NF) and rubber plantation (RP), respectively, in Xishuangbanna, SW of China. Research was conducted over 1 year during May, June and October 2015 (wet season) and January and March 2016 (dry season). Soil respiration rates ranged from 1.4±0.2 to 8.4±0.3 μmol·m⁻²·s⁻¹ in NF and 0.74±0.1 to 6.8±1.4 μmol·m⁻²·s⁻¹ in RP. Average soil respiration rates decreasing from June to January: 4.4±0.4 μmol·m⁻²·s⁻¹ to 2.3±0.3 μmol·m⁻²·s⁻¹ in NF and 3.5±0.4 μmol·m⁻²·s⁻¹ to 1.4±0.2 μmol·m⁻²·s⁻¹ in RP. Soil respiration rates were higher in NF than in RP. In RP slope position had no significant effects on soil respiration, but soil respiration rates in NF were positively correlated with higher slope position. These results contribute to our understanding of the effects of land use on soil respiration and will enable more accurate modeling of carbon dioxide emissions.


Taxonomic revision and phylogenetic analyses of rubber powdery mildew fungi

by Sehroon Khan 1, Kapila K. Liyanage 2, Siraprapa Brooks 3, Peter E. Mortimer 4, Samantha C. Karunarathna 5, Uwe Braun 6, Jianch Xu 7, Kevin D. Hyde8
1 World Agroforestry Centre East Asia Region, Kunming.
2 1 Center of Excellence in Fungal Research, and School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand 2 World Agroforestry Centre, East and Central Asia, Kunming, 132 Lanhei Rd, Heilongtan, Kunming, Yunnan, China
3 Center of Excellence in Fungal Research, and School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand
4 Center of Excellence in Fungal Research, and School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand 2 World Agroforestry Centre, East and Central Asia, Kunming, 132 Lanhei Rd, Heilongtan, Kunming, Yunnan, China 3 Center for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Science, Kunming 650201, Yunnan China
5 World Agroforestry Centre, East and Central Asia, Kunming, 132 Lanhei Rd, Heilongtan, Kunming, Yunnan, China 3 Center for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Science, Kunming 650201, Yunnan China
6 Department of Geobotany and Botanical Garden, Herbarium, Institute of Biology, University of Halle-Wittenberg, D-06099 Halle, Saale, Germany
7 World Agroforestry Centre, East and Central Asia, Kunming, 132 Lanhei Rd, Heilongtan, Kunming, Yunnan, China 3 Center for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Science, Kunming 650201, Yunnan China
8 1 Center of Excellence in Fungal Research, and School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand 2 World Agroforestry Centre, East and Central Asia, Kunming, 132 Lanhei Rd, Heilongtan, Kunming, Yunnan, China

Powdery mildew is a fungal disease that infects a wide range of plants, including rubber trees, which results in a reduction of latex yields of up to 45%. The causal agent of powdery mildew of rubber was first described as Oidium heveae, but later morpho-molecular research suggested that in the past, O. heveae has been confused with Erysiphe quercicola. However, it is still under debate whether the causal agent should be classified as a species of the genus Erysiphe emend. or Golovinomyces and Podosphaera, respectively. Therefore, the aim of this study was to undertake the morpho-molecular characterization of powdery mildew species associated with rubber trees, thus resolving these nomenclatural issues. Morphological observation under light and scanning electron microscopes (SEM) clearly identified two morphotypes of the rubber powdery mildew. With the support of morphological and phylogenetic data, one of the two morphotypes was identified as the asexul morph of E. quercicola, while the second morphotype is still insufficiently known and according to the morphological results obtained we assume that it might belong to the genus Golovinomyces. More collections and additional molecular data are required for final conclusions regarding the exact taxonomic position of the second morphotype of rubber powdery mildew and its relation to the name O. heveae. The haplotype analysis identified eight haplotype groups of E. quorcicola indicating the high genetic diversity of the species.


Community analysis of litter ants in forest fragments and rubber plantations in Xishuangbanna

by Shenxian Hui1
1 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences

With the rapid expansion of rubber cultivation and the dramatic decline of forest, biodiversity has been affected detrimentally in Southeast Asia. Assessing the species diversity among different landscapes is critical for effective conservation management. Ants, play an important role in pollination services, decomposition reaction, seed dispersal and nutrient cycling, and could form important indicators for habitat condition and quality. In order to reveal the effect of the expansion of rubber plantation on litter ants, we compared the species richness, diversity and community composition of litter ants from forest fragments and adjacent rubber plantations collected by Winkler extractor in Xishuangbanna, Yunnan province in November of 2013. A total of 1562 ants were collected ( 478 individuals from rubber representing 34 species or morphospecies; 1084 individuals from forest representing 39 species or morphospecies), representing 58 species or morphospecies, 23 genera and 5 subfamilies. The common species of litter ants in forests and rubber plantations were both Nylanderia sp.1. The species richness and Shannon-Wiener diversity index of litter ants in rubber plantations were significantly lower than those in forest fragments (p < 0.01). The species richness and diversity index were significantly and positively correlated with the litter-depth in both rubber and forest. NMDS analysis indicated that the community composition of litter ants associated to different vegetation were different, but the community dissimilarity among rubber plantations was bigger than forests. There were 4 indicator species (Solenopsis sp.1, Strumigenys strygax, Pheidole sp.1 and Pheidole sp.1) in forests, but no one in rubber plantations. In addition, opportunists group of litter ants in rubber plantations are more than in forests. These results show that habitat environment in rubber plantations are instable, and can not support specialized species. Our study highlighted that ant communities can reflect the land use changes that have taken place in Xishuangbanna.


Land Use and Impact of Soil Aggregate Size

by Zhila Hemati 1, Xiaodong Yang2
1 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences. Menglun, Yunnan 666303, China
2

Soil aggregate stability is a key factor of soil resistivity to mechanical stresses, including the impacts of rainfall and surface runoff, and thus to water erosion. When soil aggregates break down, finer particles are produced, which are easily carried away by wind and water flow and which upon re-sedimentation tend to clog soil pores, leading to the formation of soil crusts. This study is therefore aimed at evaluating the influence of land use type on soil aggregate size and the relationships between bulk density and the soil aggregate stability. In a study conducted at the two forest areas of tropical China both located within the Yunnan Province. Each forest areas, is divided into three existing land-use forests types namely “rainforest”, secondary forest” and “rubber plantation”. Soil samples from 0-10 cm and 10-20 cm depths were collected under three different transect and dry sieved into aggregate size fractions of 5-2, 2-0.5, 0.5-0.25, and <0.25 mm. The most macro-aggregate fractions in all study were between 2-0.5 mm. The aggregate stability of the size fractions decreased with increase in aggregate size. The MWD was significantly (P<0.05) positively correlated with aggregate size. Soil tillage and cultivation such rubber plantation reduced the aggregate size and carbon storage in the soil. Its suggested that with proper management of land use can make rubber plantation friendly with environment, it can increase the aggregate size and it will be protect soil from erosion.


Impact of Three Rubber Agroforestry Systems on Soil Functionalities and Diversity

by Phantip Panklang 1, Aurore Beral 2, Monrawee Peerawat 3, Treenuch Promnok 4, Uraiwan Tongkaemkaew 5, Sayan Sdoodee 6, Frederic Gay 7, Philippe Thaler 8, Alain Brauman9
1 Faculty of Natural Resources, Prince of Songkla University, Thailand
2 CIRAD, UMR ECO&SOLS, Agro Paris Tech, France
3 Land Development Department, LMI LUSES, Thailand
4 Faculty of Agriculture, Khon Kaen University, Thailand
5 Faculty of Technology and Community Development, Thaksin University, Thailand
6 Faculty of Natural Resources, Prince of Songkla University, Thailand
7 CIRAD, UMR ECO&SOLS, DP HRPP, Montpellier, France
8 CIRAD, UMR ECO&SOLS, DP HRPP, Kasetsart University, Bangkok, Thailand
9 IRD, UMR ECO&SOLS, LMI LUSES, LDD, Bangkok, Thailand

Compare to rubber monocropping, rubber based agroforestry systems (RAF), has been showed to improve economic, social, biological value and improved ecosystem services such as carbon sequestration and soil-water conservation. However, there is still few evidences on the real benefit of rubber agroforestry systems on the soil bio functioning i.e functions such as carbon degradation, soil respiration, soil infiltration or nutrient cycling originated from biotic assemblages. The objective of this study was to compare the respective impact of rubber agroforestry practices and rubber mono-cropping systems on soil biodiversity and related soil functions link to soil fauna and microbiota of the soil in comparison with rubber monoculture. We chose to work on three main models of RAF, commonly used in agroforestry in South Thailand: Pak Liang (a native vegetable shrub species), mangosteen and timber trees. Each RAF was compared with the closest monoculture rubber of the same age (from 10 to 25 years old). A preliminary farmers survey showed that agricultural practices were similar between RAF and monocropping sites. Altogether, this study showed few significant differences between RAF and monoculture on soil properties, soil biodiversity and functions. The only significant differences were found in both timber and mangosteen old plantations (~20 years old) for some biological activities such as cast productions and soil aggregation. Contrary, old shrubs plantations have a negative impact on soil compared to rubber monocroping. If these results underline that the beneficial effect of agroforestry systems take time (>20 years old) in this specific context, we also hypothesis that these weak differences was due to the fact that monoculture show often higher level of plant diversity and soil coverage due to important level of weeds.


Impacts of fertilizers application on CO2 emissions in Rubber (Hevea brasilensis) Plantation in Xishuangbanna, SW China

by Yiping Zhang 1, Yuxin Dong 2, Wenjun Zhou 3, Liqing Sha 4, Youxing Lin 5, Yuntong Liu6
1 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
2 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
3 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
4 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
5 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
6 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences

Human activities have a significant influence on soil CO₂ emissions. Rubber trees are being planted in Xishuangbanna prefecture since long and the application of the fertilizers is a major part of plantation management. This study was carried out to investigate the effect of fertilizer application on the soil CO₂ emissions in the rubber plantations of Xishuangbanna prefecture. Four plots were established within a rubber plantation in Xishuangbanna Tropical Botanical Garden under different treatments, i) fertilizer application in spring only ii) fertilizer application in autumn only iii) application in both in autumn and spring and iv) control (no fertilizer). Static chamber gas chromatograph was used to monitor CO₂ emissions across the study period. The study revealed that: (1) The seasonal changes in CO₂ emissions under all treatments (and control) were similar: emissions peaked during May, and were at their lowest level in January; (2) Soil CO₂ emission were higher in all the plots during the rainy season than the dry season, and the total annual emissions ranged from 7.88~7.93 t C • ha⁻¹ • yr⁻¹; (3) Different soil CO₂ fertilization treatments produced higher CO₂ emissions than in control. There were two peaks of CO₂ emision per year, corresponding to spring and autumn fertilization period .The difference between the rest of the months was more gentle; (4) Fertilization treatments to some extent, can promote soil respiration, causing slight increase in soil CO₂ emissions, but the difference was not significant (p>0.05).Overall fertilization has no significant effect on soil CO₂ emissions in rubber plantation. The results of this study reveals the rubber carbon cycling processes and provide a scientific basis for the sustainable management of rubber plantations.


Mekong Sentinel Landscape: Monitoring social-ecological processes at landscape scales

by Manichanh Satdichanh 1, Rhett D. Harrison 2, Jianchu Xu 3, Leigh Winowiecki 4, Tor-Gunnar Vagan 5
1 Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China
2 World Agroforestry Centre
3 World Agroforestry Centre & Kunming Institute of Botany
4 International Centre for Tropical Agriculture
5 World Agroforestry Centre

The Sentinel Landscapes programme is a CGIAR collaborative project to establish a network of landscapes for monitoring socio-ecological processes. Currently there’re six main regional Sentinel Landscape Project included Mekong Sentinel Landscape. In the recent decades, rubber plantations have expanded in South China and SE-Asia countries, which has led to deforestation, land degradation and put many ecosystem services at the critical condition. The Mekong Sentinel Landscapes was established to provide a baseline on biophysical and socio-economic conditions in this region and understand the impacts of land use change on socio-ecological processes. Mekong sentinel landscape project was implemented in four locations. The land degradation survey and socio-economics survey were implemented at two SL sites: Manlaxiang, Xishuangbanna, China and Mengbeng, Oudomxay Province, Laos in 2014-2015 using the Land Degradation Surveillance Framework (LDSF) and Sentinel Landscape Household Module (SLHM). This poster presents the preliminary analyses and characterisation of the landscape from the datasets collected in Manlaxiang, Xishuangbanna and Mengbeng, Oudomxay.


Livelihoods and gender in rubber landscapes in China and Laos

by Charlotte Filt Mertens 1, Dietrich Schmidt-Vogt2
1 Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark and Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
2 Mountain Societies Research Institute, University of Central Asia, Bishkek, Kyrgyz Republic

Landscapes in tropical areas are in many places undergoing a significant transformation from previous swidden-fallow systems to landscapes dominated by tree monocultures (Koh & Wilcove 2008; Ziegler et al. 2009). Such is also the case in the Upper Mekong Region, where rubber plantations have expanded substantially over the past decades. The expansion has been driven by a growing demand for natural rubber and policies supporting rubber plantations as a tool to address rural development. While there is a general consensus, that the expansion of rubber plantations has had a negative effect on ecosystem functions, it is unsure how it has affected local livelihoods and communities. Rubber plantations have previously been appraised for their poverty alleviating properties for local producers. However, with the drop of rubber prices in 2011, the economic benefits of rubber plantations can be questioned, along with how the land use changes have impacted work tasks, livelihood strategies, changes in wellbeing and natural resource management. Especially in the context of gender sensitive livelihoods, where gender norms often entail that men and women have different roles in agriculture, natural resource management, and participation in decision-making (Djoudi et al. 2012; Schubert 2012; Biodiversity International 2014). Based on four case studies in respectively Xishuangbanna, China (2), and Oudomxay, Laos (2), this study examines the inter- and intra-community impacts of rubber farming, using mainly qualitative methods. Preliminary results indicate that rubber farming has had varied local success. The shift to cash-crop farming has generally increased local incomes and family wellbeing, but rubber farming is challenged by diminishing profits, leading in many cases to local disinterest and abandonment of rubber plantations. Although family members share the agricultural work, rubber farming remains male-dominated and has not challenged existing gender norms.


Effectiveness of protected areas in preventing rubber expansion and land conversion in Xishuangbanna

by Chaya Sarathchandra 1, Rhett D. Harrison 2, Jian-Chu Xu3
1 Centre for Mountain Ecosystem Studies, Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences
2 World Agroforestry Centre, East & Southern Africa Region
3 World Agroforestry Centre, East and Central Asia Regional Office, Kunming 650201, China, Centre for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Sciences

Protected areas (PAs) are one of the most important conservation tools. By 2010, Xishuangbanna had designated an area of 3455.52 km²as PAs, constituting to 17.99 % of total land. In China rubber is an economically important plant and has expanded rapidly to occupy considerable land area, including highly diverse rainforests in Xishuangbanna (22% of land by 2010 with a rubber expansion rate of 269.67 km² y⁻¹). Our goal was to assess the effectiveness of PAs in preventing expansion of rubber and other non-conservation land uses within their boundaries. We created 19,744 cells of 1km²*1km²covering Xishuangbanna and sampled these according to their location inside different PA zones (Core, Buffer, Transition) and outside of PAs. Annual land use conversion rates were calculated for each of the main land use type identified after analyzing each cell in detail for their temporal land use changes between 2002 – 2010 to assess the protection performance. Propensity scores was used to match protected and unprotected cells of similar geographical features; mean average slope &amp; elevation, and mean average distance to roads and rivers. Paired-samples t-test was used to compute significance of differences in deforestation rates. In 2002 Xishuangbanna recorded a forest cover of ~71%, which was reduced to 55% by 2010 with deforestation and rubber expansion rates of 374 km² y⁻¹and 269.67 km² y⁻¹, respectively. During 2002-2010 deforestation rates inside PAs (436.59 km² y⁻¹, 18.2%) were found to be higher than that of outside PAs (-62.58 km² y⁻¹, -2.6%). However, rubber expansion rates inside PAs were lower than outside PAs, suggesting a positive role of PAs in preventing rubber expansion but not in preventing deforestation. Further analysis is underway to identify the threats that are driving deforestation within PAs in the Xishuangbanna landscape.


Taxus mairei as potential intercropping plant in rubber plantations

by Xiaomin Yu 1, Dr. Gerhard Langenberger2
1 University of Hohenheim
2 University of Hohenheim

The rapid expanding of rubber tree’s mono-cultivation in Southeast (SE) Asia has had a strong negative impact on local environments and small-holders’ livelihoods. To cultivate rubber in a more sustainable way, intercropping schemes have been suggested as an alternative. In this study, first data of Taxus mairei intercropped with rubber trees from the SURUMER-demo sites will be discussed, together with a systematic review on the cultivation, management and existing intercropping schemes of T. mairei in China. In conclusion, T. mairei could be a unique intercropping plant in rubber plantations. Rubber trees could provide shades to T. mairei seedlings, while land-use efficiency, soil conditions and local biodiversity of the rubber plantation could be improved. Our data from the SURUMER-demo sites so far verifies this conclusion. Additionally, more market value could be created in this intercropping scheme. For small-scale farmers in SE Asia, intercropping T. mairei with rubber can be considered as a good livelihood strategy to eliminate livelihood vulnerabilities.


Rubber agroforestry systems in Indonesia and Thailand for a sustainable agriculture and income stability.

by Eric Penot1
1 CIRAD UMR Innovation

Promoting environmental friendly and socially responsible rubber cultivation is relatively new in current agricultural policies in Asia. However rubber based agroforestry systems are very old, their interest and recognition is relatively recent (the 2000’s). If rubber has been introduced in South Asia as a colonial crop, it has been immediately adopted by local farmers and developed as a very extensive agroforestry system based on unselected rubber seedlings: the jungle rubber, in Indonesia, Malaysia (North-Borneo) and southern Thailand. Very early, Malaysia in the 1950’s and Thailand in the 1960’s developed specific institutions and policies to replace jungle rubber by clonal monoculture and implement rapidly highly productive new plantations when Indonesia began in the 1970’s where there is still between 1 and 2 million hectare of jungle rubber. Meanwhile, local famers began to experiment by themselves in the 1990’s agroforestry practices with clonal rubber trough association of rubber to fruits trees, wood/timber trees and other plants susceptible to produce a diversified source of income (roots, tubers, rattan, medicinal plants, vegetables…). Such systems have been documented in the 1990’s in Southern Thailand (4 % of the total rubber area) and mainly in Kalimantan and Sumatra in Indonesia) and research began to have interest in optimizing existing farmers agroforestry practices (PSU/TU/KKU in Thailand, the SRAP/ ICRAF project in Indonesia…). The rubber price volatility has left many farmers vulnerable to global market fluctuations. Strategies of income diversification became priority and in a context of land scarcity agroforestry appears as the best-bet alternatives to combine productions. Local extension or research institutions began to recognize agroforestry as valuable practices to overcome monoculture constraints (relying on one source of income only, rubber prices volatility…) and profit from environmental services. The presentation focus on 20 years of research and improvement of rubber based agroforestry systems in Indonesia and Thailand.


SURUMER – A framework for sustainable rubber cultivation

by Georg Cadisch1
1 University Hohenheim, Stuttgart, Germany

The shift from tropical forests and traditional swidden agriculture to large-scale rubber monoculture further has resulted in the loss of ecosystem services (ESS) and significant changes in ecological functions (ESF), and human welfare. Solutions to reduce such adverse effects are addressed within the German-Chinese BMBF-funded project SURUMER (Sustainable rubber cultivation in the Mekong region). The project encompasses biophysical and socio-economical aspects directed to 1) analyzing and quantify major ecosystem functions affected by rubber cultivation and their effects on ecosystem services; 2) development of alternative and more sustainable rubber cultivation systems within a transdisciplinary framework; and 3) establish ecologically and economically sustainable concepts based on the evaluation of trade-offs and synergies between ecological and economic goals and providing baseline models applicable to other tropical land uses, especially to production systems of renewable resources. Results based on cross section data of 600 rubber farmers in Xishuangbanna, suggest that over 20% of farmers are operating below break-even point and are vulnerable to price fluctuations. Additionally, field investigations revealed that intercropping and improved weed management (e.g. reduced herbicide applications) could reduce soil erosion by 40-70% and decrease of environmental pollution (i.e. sediment loads into river (e.g. by 15%) and improve drinking water supply) and at the same time increase plant biodiversity. Rubber monocrops provide only limited habitats for wild bees and larger animals necessitating access to forest refugees/corridors within a radius of about 600m. Intercropping with medicinal and endangered trees, and an ecologically and policy supported spatially zoned landscape design are potential alternative approaches to overcome the increasing lack of labor resources, diversify production and at the same time enhance biodiversity and environmental services (water quality, quantity and C sequestration). A balanced landscape design is thus needed particularly in the context of recently falling rubber prices, competition with food crops and expected climate change impact.


Flemingia macrophylla introduced to the rubber plantation mitigates soil acidification processes and improved soil available phosphorus in Xishuangbanna, Southwest China

by Xin Rao 1, Jianwei Tang 2, Chang-An Liu3
1 Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
2 Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
3 Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences

Due to economic demands, tropical rainforest in Xishuangbanna, southwest China, have been deforested and replaced with > 470000 ha of rubber plantations, this being 24.6% of the total land area. pH is known to be a primary regulator of nutrient cycling in soil, and it can affect the forms of phosphorus (P). Application of nitrogen fertilizer and sulfur spraying in rubber plantations may result in soil acidification. The rubber- Flamingia macrophylla intercropped systems with reducing the input of nitrogen fertilizer have been popularized wildly in Xishuangbanna. However, the effect of Flemingia macrophylla introduced to the rubber plantations on soil acidification processes and soil available phosphorus remains unknown. In this study, we investigate the impact of Flemingia macrophylla introduced different year-old rubber plantations on soil acidification processes and soil available phosphorus. The results showed that soil pH and available P contents decreased, in the 0-90 cm soil layer with the increase of rubber plantation chronosequence at three sites (Miandi, Juzidi and Longlin). Flemingia macrophylla introduced to the different year-old rubber plantations mitigates soil acidification processes and improved soil available phosphorus (AP). After growing 4 years, the decrease of soil pH in the 5, 8 and 17 year-old rubber plantations occurred in the 0-90 cm soil layers, while its decrease only occurred in the 0-30 cm soil layers in the 5, 8 and 17 year-old the rubber-Flamingia macrophylla plantations in Longlin. Soil exchangeable Al increased with the increase of rubber plantation chronosequence. Flemingia macrophylla introduced to the different year-old rubber plantations also decreased soil exchangeable Al. These results suggest that application of nitrogen fertilizer and sulfur spraying in rubber plantations leads to soil acidification and decreases soil available P contents, and Flemingia macrophylla introduced to the rubber plantation mitigates soil acidification processes and it is propitious to maintain soil available P contents.


Could sustainable agricultural practices buffer the impact of rubber tree monocropping on soil biodiversity? Case of rubber plantations in Northeast Thailand

by Peerawat Monrawee 1, Nimkingrat Prakaijan 2, Gay Frederic 3, Kyulavski Vladislav 4, Promnok Treenuch 5, Till Milena 6, Junrungreang Supaporn 7, Suvannang Nopmanee 8, Brauman Alain9
1 LDD, Dept of Biotechnology, LMI LUSES, Bangkok Thailand
2 Faculty of Agriculture, LMI LUSES, Khon Kaen University, Khon Kaen, Thailand
3 CIRAD, Kasetsart University – Bangkok Thailand
4 IRD, LDD, Dept of soil science, LMI LUSES, Bangkok Thailand
5 Faculty of Agriculture, LMI LUSES, Khon Kaen University, Khon Kaen, Thailand
6 IRD, LDD, Dept of soil science, LMI LUSES, Bangkok Thailand
7 LDD, Dept of Biotechnology, LMI LUSES, Bangkok Thailand
8 LDD, Office of Science for Land Development, LMI LUSES, Bangkok Thailand
9 IRD, Research Unit Eco&Sols, Montpellier

Perennial crop plantations expend quickly in South-East Asia, stimulated by a rising demand on their deriving resources. Recent extension of Rubber plantations over poor and shallow soils in the North-Eastern part of Thailand threats the sustainability of these plantations. In this study, we hypothesize that in this adverse ecological context, sustainable agricultural practices will be the main factor to reduce the impact of rubber tree mono-cropping on soil biodiversity and related functions. To address this question, we measured the occurrence of three major groups of soil organisms (macrofauna, nematofauna, microorganisms), submitted to a gradient of intensity of land management practices. These 3 groups are considered as bio-indicators of physical or chemical perturbations induced by agricultural practices. Sampling was made on 12 representative plots in Khon-Kaen province, with (i) two levels of practices intensity, high (tillage, mechanical weeding, intercropping) and low (no tillage, no intercropping, manual weeding) , and (ii) two levels of plantation’s age, (immature <6 years old, mature > 6 years old). Intensive agricultural practices had generally negative effect on soil biota, homogenizing both microbial catabolic structure, and nematodes functional one and last but not least, reducing functional diversity for all groups of organisms studied. Contrarily, Plantations with low intensity practices showed an increase of microbial biomass, soil engineers (earthworms and termites) and a broader metabolic spectrum of the microbial community. The impact of intensive agricultural practices on soil biota was higher for immature plantation than for mature one, du probably to a lowering of practices intensity (no intercropping, less tillage) in mature plantation. Moreover, the higher level of stability (more complex food web), found in mature planation seemed to buffer the perturbations induced by previous agricultural practices. Our study clearly shows that in this adverse ecological context, land management constitutes the main solution to maintain soil sustainability.


Are rubber-based agroforestry systems effective in controlling rain splash erosion?

by Wenjie Jie1
1 Xishuangbanna Tropical Botanical Garden, CAS

In order to evaluate the influence of different types of rubber-based agroforestry systems on soil erosion processes, rainfall and throughfall erosivity (splash erosion potential) were measured in an open field environment and under different vegetation types using sand-filled Tübingen splash cups. Our results indicate that the splash erosion potential under rubber monoculture was, on average, 3.12 times greater than those in the open environment. Splash erosion potential under agroforestry systems was higher than that of an open environment (ranging from 1.22 to 2.18 times greater), except for the rubber and tea system (0.87 times the open environment). However, in all but one system (the rubber and orange system), there was a significant reduction in splash erosion beneath multiple canopies compared to monoculture, especially for the rubber and tea system (0.27 times the monoculture) where it had high sub-canopy closure and low sub-canopy height. The erosion potential under the forest is closely related to the forest structure, especially height and canopy cover. These results indicate that low canopy height with high sub-canopy coverage is the major control on the amount of splash erosion, regardless of how the splash potential is increased by the canopy above. These results highlight the importance of selecting low near-surface intercrops for constructing rubber-based agroforestry systems. This also accentuates the importance of an intact litter layer in rubber plantations to protect the soil against splash erosion. Disturbance of these forests by latex tapping activities, herbicide application and removal of the litter layer during fertilization, for example, will also lead to higher actual splash erosion rates inside the forests in comparison with the open environment.


Mitigating Monoculture Rubber Plantation with Analog Agroforestry System

by Hilario Padilla 1, Joanne Li2
1 Kadoorie Farm and Botanic Garden
2

China is the world’s largest natural rubber-consuming country and ranks 6th in global rubber production. Hainan Island is its largest rubber production base. Almost every village household surrounding protected areas in Hainan is financially dependent on rubber. Lowland forests are cleared and planted with mono-crop rubber, the biodiversity value of the original forests are lost, and their ecological services further degraded by the heavy usage of chemicals. Ecologists are calling for diversification of rubber monoculture to restore some of the biodiversity value and ecosystem functions; however, identifying suitable shade-loving crops and changing the mono-cropping mindset of farmers prove to be challenging. In Hainan, we are promoting the idea of Analog Agroforestry, in which the crops selected imitates the original native forest and has similar structures and ecological functions. We have been intercropping a native medicinal plant cardamom Alpinia oxyphylla under rubber monoculture, and diversifying the rubber agroforestry system to include high value shrubs and timber trees. Furthermore, we are integrating the keeping of native Chinese bee within the system to aid pollination and increase yield. Farmers get higher income with the system, they stopped spraying herbicides in the rubber plantation, and the trimmings act as mulch increasing soil organic matter and water retention capacity. The adoption of analog agroforestry may provide a brighter future for the expansive rubber plantation throughout Indochina.


How does interspecific competition for water in rubber agroforestry help improve the water use of rubber trees?

by Junen Wu1
1 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences

The dramatic expansion of rubber plantations in mainland Southeast Asia and Southwest China has caused many eco-environmental problems, especially negative hydrological consequences. Although rubber-based agroforestry systems are regarded as the best solution for improving the sustainability of rubber agriculture and environmental conservation, plant water use and related interactions have rarely been examined in such systems. We primarily used stable isotope (δD, δ¹⁸O, and δ¹³C) methods to test whether intercropping could improve the water use of rubber trees in three types of promising agroforestry systems (i.e. rubber with tea, coffee, and cocoa) in Xishuangbanna, China. We found that the rubber tree is a drought-avoidance plant with strong plasticity with respect to water uptake. This characteristic is reflected by its ability to cope with serious seasonal drought, allowing it to avoid interspecific competition for water. The rubber trees showed wasteful water behaviour unless they were intercropped with tea or coffee. However, these intercropped species exhibited drought-tolerance strategies and maintained lower water use efficiencies to strengthen their competitive capacity for surface soil water. Our study suggests that interspecific competition for water can enhance the water use efficiency of rubber trees and lead to complementarity between the root distributions of plants in rubber agroforestry systems. In our study, tea was the most suitable intercrop in terms of water use because the interspecific competition for water was moderate and the agroforestry system retained much more soil water and improved the water use efficiency of the rubber tree. Considering the root characteristics of the tea trees, we suggest that the crops selected for intercropping with rubber trees should have a relatively fixed water use pattern, short lateral roots and a moderate amount of fine roots that overlap with the roots of the rubber trees in the shallow soil layer.


Effects of biochar addition on soil properties and carbon sequestration of rubber plantation in Xishuangbanna, SW China

by Sha Liqing 1, Pan Libing 2, Xu Fanzhen3
1 XTBG
2 XTBG
3 XTBG

In Xishuangbanna large area of rain forest has been cleared for rubber plantation, which brings great income to farmers, but has caused severe damages to environment, such as biodiversity loss, soil erosion, chemical fertilizer and pesticide pollution, water resources deficit. Mono rubber plantation will decrease quality and quantity of soil organic matter, exhaust soil nutrients, and soil ecological fertility can not maintain high rubber productivity in long time scale. Agro-forestry is a common way to improve soil fertility, but in tropical area it is very difficult to increase soil organic matter. In this study we applied biochar, transformed from plant litter, to soil under rubber plantation. Tropical tree species also were interplanted in rubber plantation. Understanding the effects of biochar and interplanted trees on soil fertility maintenance and carbon sequestration is essential for sustainable development of rubber plantation. We conducted biochar experiments in field and in pot. The results showed that (1) Biochar significantly improved soil fertility; (2) Reduce soil nitrate, ammonium and phosphate leaching; (3) Biochar had little effect on soil temperature, but significantly improved soil water content.; (4) Biochar reduced the response of soil respiration to soil temperature. Biochar can be an effective and practicable path to improve carbon sequestration in rubber plantation.


Modelling the impact of rubber expansion on carbon stocks in landscape

by Sergey Blagodatskiy 1, Carsten Marohn 2, Xueqing Yang 3, Moritz Laub 4, Jianchu Xu 5, Georg Cadisch6
1 University of Hohenheim
2 University of Hohenheim
3 KIB, University of Hohenheim
4 University of Hohenheim
5 ICRAF
6 University of Hohenheim

Expansion of rubber plantations in South-East Asia has presumably altered ecosystem based carbon (C) stocks affecting thus climate change mitigation and future C trading opportunities. However, reliable estimations of carbon sequestration and emission at the landscape level after this land cover transition are missing. We studied C stocks in main land use types in Naban River National Reserve in Xishuangbanna, South-East China and evaluated two contrasting scenarios of land development impact on the C sequestration potential in this region. The baseline scenario assumed the rubber expansion keeping the rate recorded in past 20 years for this region, i.e. 2% per year. The sustainable rubber development scenario corresponding to 12th governmental 5-year plan assumed reforestation at territories suboptimal for rubber planting, i.e. at steep slopes and elevations above 900 m a.s.l. The series of land cover maps were produced by land use change generator according to rules adopting the selected scenarios and further used for analysis of aboveground carbon stocks in landscape. Land Use Change Impact Assessment (LUCIA) model was applied for simulation of all major ecosystem carbon stocks dynamics in landscape. Significant (up to 2,3 times) increment of AGC in rubber plantations was not able to compensate 18% loss of forest carbon in the nature reserve under baseline scenario. Limitation of rubber expansion under conditions of sustainable development scenario helped to increase C stocks in landscape by one third with most significant contribution of regrown highland forest. Mapping of soil C stocks until the 1m depth proved that this pool was the largest and more stable part in the considered ecosystems. We did not found significant drop in soil C driven by forest to rubber conversion. Further analysis of model results in respect to other C pools, e.g. collected latex, will give information necessary for interdisciplinary evaluation of tested scenarios.


Ecological process-based modeling for predicting rubber tree growth and latex yield under climate change

by Xueqing Yang 1, Hongxi Liu 2, Sergey Blagodatsky 3, Carsten Marohn 4, Reza Golbon 5, Jianchu Xu 6, Georg Cadisch7
1 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), Stuttgart, Germany
2 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), Stuttgart, Germany
3 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), Stuttgart, Germany
4 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), Stuttgart, Germany
5 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), Stuttgart, Germany
6 World Agroforestry Centre (ICRAF), China & East Asia Office c.o. Kunming Institute of Botany, Kunming, China
7 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), Stuttgart, Germany

Rubber (Hevea brasiliensis Müll. Arg) plantations serve as an important source of natural latex, timber, bio-energy and seed oil. With increasing worldwide natural rubber consumption, rubber plantations have expanded into non-traditional cultivation regions with cooler temperature and distinct dry seasons. Against the global warming background, many studies tested the future distribution ranges of rubber plantations, while information about the physiological response of rubber tree to climate change is still scare. In order to better understand the dynamic process of biomass partitioning and latex production in rubber systems, and distinct response of rubber located in suitable as well as marginal highland areas to future climate change, we combined empirical measurements on sites and process-based Land Use Change Impact Assessment (LUCIA) model. Field dataset from rubber plantations sampled in the Naban Watershed National Nature Reserve (NRWNNR), Xishuangbanna, were used to calibrate and validate plant growth parameters in the model. Compared with highland rubber plantations, model simulations showed that lowland rubber plantations produced higher total biomass (60 Mg ha⁻¹) and latex yield (18.3 Mg ha⁻¹) within a 35-year rotation. Shift from current CO₂ emission scenario (Baseline) to a high CO₂ emission scenario (RCP 8.5, 2050) decreased lowland rubber plantations’ total biomass and cumulative latex yield by 4 % and 43% respectively, while highland rubber plantations showed an increase of 23% and 27% accordingly. Based on the intrinsic nature of tree development, modeling results could guide identifying appropriate future cultivation areas of various rubber genotypes, and be integrated with social-economic information to evaluate trade-offs between optimization of tree growth and maximization of economic benefits under climate change. In rubber cultivation regions, the accompanying economic risk with low net present value, and poor silvicultural management strategies (such as planting density, tapping frequency) in highland rubber plantations should also be emphasized in conducting sustainable rubber management.


Management of herbicide usage in rubber plantations with help of modeling erosion and crop growth

by Hongxi Liu 1, Xueqing Yang 2, Sergey Blagodatskiy 3, Carsten Marohn 4, Georg Cadisch5
1 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Garbenstraße 13, Stuttgart, 70599, Germany
2 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Garbenstraße 13, Stuttgart, 70599, Germany
3 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Garbenstraße 13, Stuttgart, 70599, Germany
4 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Garbenstraße 13, Stuttgart, 70599, Germany
5 Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Garbenstraße 13, Stuttgart, 70599, Germany

Land use in Xishuangbanna, SW China, a typical tropical rain forest region, has dramatically changed over the past 30 years as forest was converted into rubber plantations. This land use change induced soil loss. Reduced herbicide management has proven an efficient way to reduce plot level erosion by increasing plant and litter cover. However, efficiency of land management (reduced herbicide) regarding erosion mitigation at watershed level as well as long-term effects of land management (e.g. on latex production) remain unclear. In order to provide a comprehensive assessment, we firstly calibrated and validated a physical-based crop-erosion model (Land Use Change Impact Assessment, LUCIA) by simulating short-term (one year) effects of weed management on runoff and soil loss in an established rubber plantation (12 year age). The model was further validated to simulate long-term (20 years) growth of rubber plantations under standard weed management (twice spraying per year). Then scenarios were created to simulate soil erosion under different herbicide managements in the long run (23 years): i) totally cleared understory (H+); ii) twice weeding per year (Hs); iii) once weeding per year (H-). It was found that total soil loss in one rotation length was reduced under H- by 60% compared to Hs and 70% compared to H+. Once weeding per year (H-) can efficiently control annual soil loss below 2 t ha⁻¹ year⁻¹ with no negative impact on latex production. To evaluate effect of reduced herbicide use on watershed scale, LUCIA was further applied to a mixed land use watershed with 11% rubber plantation. Reduced herbicide use (H-) was found to decrease total sediment export by 15% at watershed level.


Riparian buffer strips as measures to reduce fine sediment infiltration into rivers in an agricultural dominated area in Southwest China

by Lydia Seitz 1, Manuel Krauss 2, Neda Azizi 3, Bertram Kuch 4, Heidrun Steinmetz 5, Silke Wieprecht6
1 Institute for Modelling Hydraulic and Environmental Systems, University of Stuttgart, Stuttgart, Germany
2 Institute for Sanitary Engineering, Water Quality and Solid Waste Management, University of Stuttgart, Stuttgart, Germany
3 Institute for Sanitary Engineering, Water Quality and Solid Waste Management, University of Stuttgart, Stuttgart, Germany
4 Institute for Sanitary Engineering, Water Quality and Solid Waste Management, University of Stuttgart, Stuttgart, Germany
5 Department of Resource Efficient Wastewater Technologies, University of Kaiserslautern, Kaiserslautern, Germany
6 Institute for Modelling Hydraulic and Environmental Systems, University of Stuttgart, Stuttgart, Germany

The aim of this study is to present a concept to reduce the introduction of fine sediments into river beds by implementing riparian buffer strips in a high monoculture dominated area. The riparian buffer strips are planned according to land use, slope and soil composition of the surrounded area. Therefore, different scenarios are developed to retain sediments by the buffer strips. The study site is located in Jinghong County, Dai Autonomous Prefecture Xishuangbanna of Yunnan Province (South China). The catchment of the Naban River, which is a tributary of the Mekong River is investigated in detail. With China´s growing economy the demand of rubber has been increasing continuously in the last decades. In the Naban River catchment, monitoring stations have been installed which measure continuously (amongst other parameters) turbidity and water level. Results show that especially after rain events turbidity values frequently rise above 3000 NTU, indicating a high soil loss from agricultural fields. To quantify the effectiveness of buffer strips, a SWAT model is used that calculates the reduction of erosion when implementing buffer strips. This model is based on the well-known USLE approach, which calculates the annual runoff based on different parameters such as land use and soil properties. In a first step, the model estimates the current annual soil loss and allows for investigating the effect of the different widths of buffer strips. The results show a significant retention of fine sediments due to the buffer strips and a reduction of the erosion risk compared to the current state. It can be concluded that riparian buffer strips are an efficient and easy-to-implement measure to reduce the introduction of fine sediments into rivers and thus to contribute essentially to the improvement of water and habitat quality in the respective rivers.


The effect of monoculture rubber plantation expanding on stream flow in Xishuangbanna, China

by Ma Xing1
1 Yunnan Institute of Environmental Sciences

With the monoculture rubber plantation expansion to steeper slope and higher elevation area in Xishuangbanna prefecture, China, the effect of rubber plantation on water resources is becoming a common concerned question. To enrich the understanding concept of the role of rubber plantation in the hydrological processes in the watershed, a typical watershed with apparent rubber expanding and long-term observed stream flow data was selected to do simulation by using a monthly lumped conceptual water balance model GR2M. The results showed the stream flow was reduced influencing by the expansion of rubber plantation. A decreasing trend and a slightly increasing trend were observed in period 1 (1992-2002) and period 2(2002-2006), respectively; which indicated rubber hydrological behaviors were dependent on the elevation, slope of rubber planted area, and rubber age.


Combining multi-disciplinary Ecosystem Service Assessments in Rubber – challenges and boundaries

by Marc Cotter1
1 University of Hohenheim

Using the approach of ecosystem services (ESS) analysis for evaluating the status of a given ecosystem, whether natural or man-made, gained much attention in the last years. While this idea is necessary to target the problem of degrading environments, it entails some practical problems. The field of ecosystem services is vast, varying from provisioning over regulating and maintaining services to cultural services. Consequently, different scientific disciplines are needed to study these different ecosystem services, from agricultural sciences over hydrology to social sciences to realize inter-/intra- and transdisciplinary assessments. As a majority of scientific research calls aims at strongly focussed research topics, many studies cover only on a limited number of ecosystem services for a given ecosystem. However, for a holistic overview which is the ultimate aim of the ecosystem service approach this is not enough. Two steps are necessary for a full assessment: first, a range of different ecosystem services from the three categories should be studied; second, the results must undergo a stakeholder based reviewing process. Often these close interactions with stakeholders from different levels of decision making hierarchies offer researchers the possibility to valuate and rank the importance of ESS. This final step is a crucial part for the success of an ecosystem service approach, it is often demanded but difficult to achieve. We have used 8 years of accumulated project data and extensive literature studies to serve as basis for an ESS Assessment using the InVEST tool combined with impact analysis from economics and social sciences. The models, scenarios and assumptions developed for this process underwent an iterative reviewing process with different stakeholder groups in order to allow for an integrative, transdisciplinary Ecosystem Service Assessment.


How meta-data analysis and data visualization can help us make better decisions for sustainable rubber cultivation?

by Zhuangfang Yi1
1 The Morton Arboretum

Asia produces >90% of global natural rubber primarily in monoculture for highest yield in limited growing areas. The majority (68%) of natural rubber latex produced in tropical East Asia is harvested by small-holders. Many of these rubber smallholders live in remote and poorly developed areas, scattered across several countries, that differ greatly in market accessibility, labor availability and cost, and potential rubber productivity. The global market for natural latex has been relatively volatile, exposing this large, widely distributed, and politically disconnected group of farmers to a considerable vulnerability in sustaining their livelihood and plantations. Additionally, the rapid conversion of large areas of natural forests into monocultures of rubber is greatly increasing the threat to the region’s rich biodiversity. I will discuss the development of guidelines on sustainable rubber, rubber green certification struggles and also present a comprehensive view of rubber production in East Asia to the local county level and answered these questions: 1) What is the geographic and socio-economic distribution of rubber plantations?  2) What is the minimum profitable price for rubber production, incorporating costs of establishing, managing and harvesting rubber? 3) How would the market incentives especially green certification program help; 4) Where are the primary locations of conflict between economic benefit and environmental cost, measured regarding biodiversity? And 5) What are reasonable policies to enhance smallholder sustainability and biodiversity conservation and at what geographic scale do things vary?


Rubber Booms, Land Policies and Land Grabs in Cambodia, Lao PDR and Myanmar

by Andreas Neef1
1 The University of Auckland

In this keynote I will look into the social and political impacts of recent rubber booms in three Mainland Southeast Asian countries with weak land governance. First, I will review the land policy frameworks in Cambodia, Lao PDR and Myanmar, with particular emphasis on their implications for indigenous peoples, ethnic minorities and women. Second, I will describe the expansion of area under rubber – predominantly in the form of agro-industrial plantations –, and elicit the mechanisms and discourses around these rubber booms. I will then discuss how these large-scale investments have affected customary land rights, rural livelihoods, state-society relations and foreign influence on domestic policy spaces. I will argue that the rapid transformation of formerly diverse rural landscapes into rubber monocultures is leading to a semi-proletarianization of the rural population and a foreignization of space in the three countries. Finally, I will explore whether declining rubber prices, increased local resistance against corporate land grabs, and new political configurations are opening new windows of opportunity for policy-makers to reconsider their lopsided emphasis on large-scale rubber production as the primary driver of economic growth in the most marginalized parts of Mainland Southeast Asia.


Using agroforestry to diversify smallholder monoculture rubber plantations: A participatory approach to development

by Gbadamassi G.O. Dossa 1, Rhett D. Harrison2
1 Kunming Institute of Botany, Chinese Academy of Sciences
2 World Agroforestry Centre, East & Southern Africa Region

In Asia, cash crop monocultures such as palm oil and rubber have expanded greatly in recent decades with serious consequences for biodiversity and ecosystem services, including negative impacts on soil heath, water supplies and carbon sequestration. In addition, focus on a single commodity crop holds an inherent economic vulnerability for smallholders. One option for addressing this situation is to intercrop monoculture with shade tolerant species, not only as a means of restoring biodiversity but also to provide short term income to farmers. We are introducing intercropping to rubber monocultures through a participatory approach in Xishuangbanna. Such a strategy requires the involvement of local smallholders from the beginning and a rigorous experimental design. The first is perquisite for success in on-farm trials and in securing the farmers’ interest and participation. A rigorous experimental approach, meanwhile, provides a strong evidence-base for decision-making and policy development. Reconciling these sometimes conflicting approaches is critical. We will present a case study of a rubber agroforestry trial which is being implemented in Man’e village in Xishuangbanna, China and document some of the lessons learned.


Enriching rubber with native tree species – a first assessment of the SURUMER demonstration sites

by Gerhard Langenberger 1, Konrad Martin 2, Georg Cadisch 3, Xiaomin Yu4
1 Institute of Tropical Agricultural Sciences, University Hohenheim, Stuttgart, Germany
2 Institute of Tropical Agricultural Sciences, University Hohenheim, Stuttgart, Germany
3 Institute of Tropical Agricultural Sciences, University Hohenheim, Stuttgart, Germany
4 Institute of Tropical Agricultural Sciences, University Hohenheim, Stuttgart, Germany

Natural rubber expansion has been a major driver of land-use change in the GMS in recent years, replacing traditional, diverse land-uses but also forests by monocultures. This has considerable impacts on Ecosystem Services and Functions. An often suggested improvement of this situation is intercropping and agroforestry, respectively. Unfortunately, besides the commonly practiced integration of sun-demanding crops during the establishment of rubber in the first two years, the adoption of permanent intercropping throughout the lifespan of a rubber plantation is scarce. This has biophysical but also socio-economic reasons. While income opportunities are the fundamental driver of any adoption by land holders, labour issues turned out to become an increasingly important aspect. Rubber management itself is already labour intensive and requires considerable skills. The integration of additional plants requires even more labour and respective skills, especially, if these crops demand a sophisticated management and logistic as most food crops do. Addressing these framework conditions in SURUMER we developed a concept based on the integration of native tree species with economic potential but also protective value into rubber monocultures. In this presentation we present the overall concept and considerations as well as a first evaluation of the demonstration sites two years after implementation.


Rubber agroforestry systems in Thailand

by Komsit Wisitrassameewong1
1 Mushroom Research Foundation

Hevea brasiliensis (commonly known as Pará rubber) is a valuable economic plant that produces a milky latex used as the primary material in the production of natural rubber. Rubber plantations in Thailand were first established in southern Thailand and later in eastern Thailand. Due to high demand and elevated prices, as well as the Thai government promotion schemes, monoculture rubber plantation areas have significantly increased in northern and northeastern Thailand. Increased monoculture plantations have had inevitable impact on biodiversity and ecosystem services in the area. The present study aims to investigate economic and ecological benefits of three different rubber agroforestry systems: simple intercropping, complex intercropping and enriched natural regeneration. Gnetum gnemon and Etlingera punicea were selected as short-term revenue generating species for intercropping in the simple agroforestry systems. Six species, including short-term and long-term revenue revenue generating species (e.g. Gnetum gnemon, Melientha suavis, Salacca zalacca, Elettaria cardamonum, Baccaurea ramiflora and Dipterocarpus alatus), were selected for the complex agroforestry system and eight long-term revenue generating species (e.g. Baccaurea ramiflora, Salacca zalacca, Shorea roxburghii, Dalbergia cochinchinensis, Castanopsis tribuloides, Dipterocarpus alatus, Azadirachta indica and Hopea odorata) were selected for the enriched natural regeneration agroforestry system. Latex yield, yield of intercrop species, growth of rubber and intercropping trees, soil health (such as nutrient concentrations, water infiltration rate and soil erosion rate), wood and litter decomposition rates, and biodiversity of bird and microorganisms will be investigated over at least three years.


Between rubber cultivation and nature conservation: Asian elephants and other wild mammals

by Franziska K. Harich 1, Anna C. Treydte 2, Tommaso Savini 3, Kriangsak Sribuarod 4, Chution Savini5
1 Department of Agroecology in the Tropics and Subtropics, University of Hohenheim, Germany
2 Department of Agroecology in the Tropics and Subtropics, University of Hohenheim, Germany
3 Conservation Ecology Program, King Mongkut’s University of Technology Thonburi, Thailand
4 Khlong Saeng Wildlife Research Station, Department of National Parks, Wildlife and Plant Conservation, Thailand
5 International College for Sustainability Studies, Srinakharinwirot University, Thailand

Overlapping resource use of wildlife and people often leads to conflicts, particularly in the face of declining natural resources. Expanding rubber cultivations continuously diminished natural wildlife habitat over the last decades. Wild animal species such as Asian elephants (Elephas maximus) frequently enter farmland in search for food and water, thereby damaging crops. Despite the economic and ecological importance of balanced wildlife populations for ecosystems, little is known about the diversity and distribution of wild mammals in rubber-dominated landscapes. We assessed the diversity and presence of mammalian wildlife and damage occurrence in rubber-dominated landscapes in Thailand, in and around the Tai Rom Yen National Park. We conducted interviews with 180 farmers about wildlife visits to their farms and related damage. We installed camera-traps at the boundary between plantations and natural forest and walked transects inside and outside of the protected area to assess wildlife presence. Through camera traps and transects, 35 wild mammal species were recorded in the forest, 25 species (71% of the total number recorded) were found at the forest boundary and only nine species were confirmed in the farmland while farmers mentioned 20 species in total. Elephants were most frequently reported to be causing damage. While around 46% of respondents had elephants coming to their farms, less than half of them (22%) experienced damage. Loss of rubber trees affected young plants that were not yet tapped in 85% of the cases. The presence and diversity of wildlife in the farmland was overall low and signs of larger animals were mainly recorded within 300 m from the natural forest. However, wildlife diversity was relatively high at the forest edge, and rubber plantations around protected areas might act as buffer zones if they are managed more wildlife-friendly, e.g. through increased heterogeneity, and if young and susceptible trees are protected efficiently.


Promoting rubber seed oil as a healthy edible oil for humans in China

by Jianchu Xu1
1 Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China & World Agroforestry Centre East and Central Asia, Kunming, China

Rubber seed oil, derived from the seeds of the rubber tree – Hevea brasiliensis, has been shown as a viable option for biodiesel production. However, few studies have investigated its potential as a nutritious, healthy edible oil for human consumption. This study evaluates using rubber seed oil for the feeding of albino mice and dairy cows based on traditional use of rubber seed for animal feed. Nutritional values and toxicity analysis have been conducted according to national standards. The Ministry of Health has officially approved the rubber soil oil as a healthy edible oil for human consumption in China. It is estimated that there is a potential production of 1.94 Mt of rubber seed oil within Southeast Asia. The collection of rubber seed for edible oil production will significantly contribute to income generation, dietary diversity and nutritional security for smallholder farmers in the SE Asia.


Assessing the welfare effects of enhanced ecosystem services provided by tropical rainforests: the example of sustainable rubber cultivation in Xishuangbanna, SW China

by Michael Ahlheim1
1 Institute of Economics, University of Hohenheim, Germany

Rubber plantations have been encroaching the indigenous rainforests in Xishuangbanna Prefecture in China’s Yunnan Province at a large scale and a high speed over the past decades. Many rare plant and animal species are endangered by this development, the natural water management is disturbed and even the microclimate in this region has changed over the past years. The present study aims at a monetary assessment of the environmental benefits accruing from a reforestation project partly reversing the deforestation that has taken place over the past years. To this end a Contingent Valuation Method (CVM) survey has been conducted in Xishuangbanna to elicit local residents’ willingness to pay for this reforestation program that converts existing rubber plantations back into forest. It is shown that local people’s awareness of the environmental problems caused by increasing rubber plantation is quite high and that in spite of the economic advantages of rubber plantation there is a positive willingness among the local population to contribute financially to a reduction of existing rubber plantations for the sake of a partial restoration of the local rainforest. These results could be used for the practical implementation of a PES (Payments for Eco-System Services) system for reforestation in Xishuangbanna. The study also shows that not only local people directly ‘consuming’ the services provided by a particular ecosystem would benefit from its protection or restoration but that also people living far away ascribe substantial value to the eco-system services provided by the rainforest in Xishuangbanna. To this end a CVM survey with 2,100 completed interviews was conducted in Shanghai as an example of a Chinese megacity far away from Xishuangbanna. We find that also people living in Shanghai are willing to contribute financially to the preservation and partly restauration of the rain forest in Xishuangbanna and its unique ecosystems. A third stakeholder group besides residents of Xishuangbanna and of Shanghai are tourists spending their holidays in Xishuangbanna. A CVM survey was, therefore, conducted with tourists in Xishuangbanna to assess their appreciation of and their willingness to pay for the preservation of Xishuangbanna’s natural heritage. It showed that also in this group many people are willing to support the preservation of the rainforest in Xishuangbanna financially.


Co-management of transdisciplinary processes: experiences from the SURUMER project

by Aenis Thomas 1, Wang Jue 2, Langenberger Gerhard3
1 Humboldt-Universität zu Berlin
2 Humboldt-Universität zu Berlin
3 University of Hohenheim

Transdisciplinary research (TDR) aims at developing applicable solutions for societal problems with integrated knowledge from various disciplines and communities. What seems a simple statement is in praxis coupled with fundamental challenges: paradigmatic changes are required of researchers, who usually are confronted with a need to leave the academic “ivory tower” and conduct activities towards application of results which include the communication with practitioners. Practitioners in turn are confronted with scientists who do not tell their results but want to establish “dialogues” and “discourses”. Such “strange” behaviour might cause discomfort particularly in societies which still are hierarchically structured as for example in rural China. For project management this is a challenge. It is impossible to plan a project in a linear way, from design via experiment/survey and analysis to publication. Adaptive Management is demanded which aims in general at an open problem solving process. On the basis of process monitoring and regular evaluations, strategies, structures and activities will be adjusted often in several “loops”, thus enabling co-learning processes within the group of scientists and between researchers and practitioners. The Chinese-German project SURUMER is looking for an integrative, applicable land use options for “Sustainable Rubber Cultivation in the Mekong Region”. Within the project, a co-management process was developed enhancing collaborative learning within the project and beyond, of practitioners and scientists from different disciplines. The presentation will discuss the innovative approach which was tested over five years, and some of its s results. Despite the time constraints and limited resources available for interaction, SURUMER has shown ways to address key issues that concern the different stakeholders, and mutually develop land management solutions, such as mitigating the negative impacts of rubber monoculture by integrating native trees and changing weed management practices. Keywords: co-management, interdisciplinary, transdisciplinary, stakeholders


Stakeholder analysis in support of joint land use decision making: Case from Xishuangbanna, Southwest China

by Wang Jue 1, Aenis Thomas2
1 Humboldt-Universität zu Berlin
2 Humboldt-Universität zu Berlin

The Chinese-German project SURUMER aims at developing integrative, applicable land use options for “Sustainable Rubber Cultivation in the Mekong Region”. For this purpose, land use changes are being analysed, and consequences of different scenarios are being modelled with respect to ecosystem services and trade-offs. Ongoing dialogues with stakeholders are seen as crucial in order to validate the resulting set of options, thus increase the likelihood of implementation. This presentation discusses the role of stakeholder analysis in a broader sense. It describes the whole approach, presents its results and application in the context of the transdisciplinary process, and discusses opportunities and constraints. The approach itself can be characterized as “participatory learning and action”: Qualitative data has been collected with a triangulation of empirical methods, analysed by the researchers from a grounded theory approach, and fed back into stakeholder dialogues and inner-consortium discussions, iteratively and reflexively. The whole process includes three pillars: 1) Identification and engagement of key stakeholders; 2) Scenario discussions with information gathered during open and in-depth interviews; 3) Analysis of power structures and communication networks to provide information on framework conditions with relevance for further implementation. Analysis shows that stakeholders are aware of the problems caused by current land-use systems. However, these problems seem not be the prior according to stakeholders’ agenda and they are lack of motivation to initiate changes. This implies that linking sustainable land-use with stakeholders’ interests and objectives could increase their motivation, e.g. including regional governmental development plan into the scenarios. In addition, external supports could be incentives for them as well, e.g. farmers welcome alternatives with financial or technical supports, and regional authorities are interested in the concrete research results and techniques. In general, stakeholder analysis is promising in support of producing scientifically robust and stakeholder-validated land use solutions.


Great Expectations: Chinese Investment in Laos and the Myth of Empty Land

by Juliet Lu1
1 UC California Berkeley

Over the last decade, Chinese companies have been granted contracts to develop vast areas of land for agribusiness concessions in Laos. These vast areas, however, rarely come under Chinese company control in full. Analysis of seven Chinese agribusiness concessions finds that a significant gap exists between the large areas initially granted to companies on paper and more modest areas they gain access to in actuality. To understand this gap, this article explores tropes of Laos as having abundant ‘empty’, ‘marginal’ or ‘underproductive’ lands ripe for foreign investment which were used by the Lao government to attract investors, and by investors to justify their projects. It argues that these tropes reflect state and investor views of land, agricultural production, and rural development, which erase the presence of existing land users and complicated systems of overlapping land uses. Furthermore, land regulations and investment procedures in Laos are still developing, and the state institutions implementing them are fragmented by disconnect and internal competition. As a result, in each land deal studied, Chinese investors encountered distinct obstacles to obtaining land, depending upon local politics, systems of land governance in the area and Chinese investor characteristics. These findings complicate common narratives regarding Chinese investors as predatory land grabbers and of host states as passive victims or corrupt rent-seekers. Whereas fragmentation among land governance institutions and tropes of rural areas in Laos as empty or underproductive are often studied as tools for extending state power and foreign investor access, in this case they have inflated investor expectations and hidden local level obstacles and barriers to land access which in end have slowed Chinese companies’ accumulation of land and resources in Laos.


Using Rubber Agroforestry for Forest Conservation in Indonesia

by Mangarah Silalahi 1, Rhett Harisson 2, Tom Swinfield 3, Asep Ayat 4, Yusup Cahyadin 5, Toto Suwito 6, Freya St John 7, Aidan Keane8
1 Burung Indonesia, Bogor, Indonesia
2 World Agroforestry Centre, East & Southern Africa region, 13 Elm Road, Lusaka, Zambia
3 Royal Society for the Protection of Birds (RSPB), The Lodge, Sandy, Becks, UK
4 Burung Indonesia, Bogor, Indonesia
5 Burung Indonesia, Bogor, Indonesia
6 Burung Indonesia, Bogor, Indonesia
7 University of Kent, UK
8 University of Edinburgh, UK

Logged forest without management is vulnerable to conversion, as can be seen from patterns of deforestation and forest degradation in Indonesia (±26 million of 80 million ha of production forest in Indonesia is open access). In addition deforestation has also occurred because there is a lack of clarity in forest tenure. Around 48.8 million people in Indonesia (CIFOR, 2004) (350 million people globally) live on forest margins (the World Bank, 2002). Weak central and local government makes law enforcement efforts difficult, poor forest governance and lack of attention to development for people in and around the forests is likely to lead to illegal logging, forest fires, and encroachment. To address these problems, the Indonesian government adopted the notion of Ecosystem Restoration Concessions (ERC) in 2004, and Hutan Harapan was issued the first ERC license in Indonesia in 2008. During the implementation of ERC Hutan Harapan a lot of problems and conflicts were encountered especially with in-migrants and poverty issues among the people living in Hutan Harapan. Agroforestry is potentially a good option for addressing these issues, as it is compatible with forest laws, restoration goals and livelihood aspirations. Agroforestry with using rubber as the main source of revenue is easy to develop as communities are familiar with rubber and jungle rubber technologies, markets are in place, it is a flexible system with potentially high value, and ecosystem services values are high and compatible with restoration goals. Hence, Hutan Harapan has initiated a plan to implement agroforestry using rubber as buffer to stop reduce encroachment, improve the livelihoods of local people and create business opportunities for the license holder.