RUBBER FEASIBILITY AT SCALE RUBBER AGROFORESTRY Executive Summary

May 2021 Rubber Agroforestry: Feasibility at Scale

PREPARED FOR MIGHTY EARTH Maria Wang Mei Hua Grantham Centre for Sustainable Futures and Department of Animal and Plant Sciences, University of Sheffield, UK [email protected] Eleanor Warren-Thomas School of Natural Sciences, Bangor University, UK [email protected] Thomas Cherico Wanger Sustainability, Agriculture and Technology Lab, School of Engineering, Westlake University, China Agroecology, University of Göttingen, Germany GlobalAgroforestryNetwork.org [email protected]

This project was conducted in a personal capacity by the authors, and not on behalf of their respective institutions. The institutions hold no liability for this work.

The work of Mighty Earth is supported by Waxman Strategies. Waxman’s work on conservation is funded in part by the Center for International Policy. Waxman is required under 22 U.S.C. § 614 to disclose that this material is distributed on behalf of the aforementioned organization, working under grant from the Norwegian Agency for Development Cooperation. Additional information is on file with the Department of Justice, Washington, D.C. Agroforestry system with coffee. Credit: World Agroforestry Centre/ S.K. Dalal 2 RUBBER AGROFORESTRY Contents

EXECUTIVE SUMMARY 3.1.1.2 Permanent and temporary intercropping 38 3.1.1.3 Markets for secondary agroforestry products 43 Definition of Rubber Agroforestry 6 3.1.1.4 Payments for ecosystem services and eco-certification for agroforestry 44 Agroforestry: livelihood, social, 3.1.2 Land and labor availability affect agroforestry profitability 45 environmental, and climate resilience effects 8 3.1.3 Yields and Productivity 47 Conclusion 16 3.1.3.1 Rubber yields 47 3.1.3.2 Intercrop yields 51 MAIN CONTENTS 3.1.4 Pests, disease and 53 3.1.5 Food security and nutrition 55 9 Executive Summary 5 3.2 Social outcomes 58 3.2.1 Gender 58 1 Introduction 17 3.2.2 Land tenure 62 1.1 The current state of the rubber industry 17 3.2.3 Other sociocultural benefits 63 1.2 Scope of the report 19 3.3 Environmental outcomes 65 2 Definition of rubber agroforestry 20 3.3.1 Climate resilience of agroforestry 66 2.1 Definition and proposed typology 3.3.1.1 Water use and drought tolerance 67 for rubber agroforestry 20 3.3.1.2 Farmers’ perceptions of climate resilience 69 2.2 Wild Rubber 27 3.3.1.3 Microclimate 70 2.3 Traditional Jungle Rubber 28 3.3.2 Climate mitigation through 71 2.4 Natural regrowth / Modern Jungle Rubber 29 3.3.2.1 Carbon accounting of rubber systems – 2.5 Permanent Intercropping 31 essential knowledge 72 2.6 Rubber as a tool for 32 3.3.2.2 Rubber vs non-rubber land uses 75 2.7 Definition of smallholdings and 33 3.3.2.3 Carbon sequestration and storage in different rubber systems 76 3 Agroforestry: effects on livelihood, social, environmental and climate resilience outcomes 34 3.3.3 Soil health and water management 79 3.1 Livelihood outcomes 35 3.3.3.1 Agroforestry methods (permanent intercropping; 3.1.1 Income diversification, economic analysis jungle rubber) 80 and livelihood resilience 37 3.3.3.2 Non-agroforestry methods (terracing, weed management) 86 3.1.1.1 Wild rubber 37 3.3.3.3 Rubber as a tool for restoration of degraded land 86

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3.3.4 Ecosystem resilience and biodiversity 86 TABLES AND BOXES 3.3.4.1 Wild rubber and agroforests in Brazil 86 3.3.4.2 Jungle rubber 87 E.S. Table 1: Rubber agroforestry practices and systems 7 3.3.4.3 Permanent intercropping 89 Box 1: Some examples of definitions of rubber agroforestry, 3.3.4.4 Non-agroforestry methods (weed man-agement) 90 from interviews and email consultations 22 3.3.4.5 Connectivity and biodiversity benefits 90 Table 1: Rubber agroforestry practices and systems 24 Box 2: Case study of smallholder livelihoods in Laos: 4 Discussion 91 land tenure, food security and agroforestry constraints 35 4.1 Barriers to Adoption of Rubber Agroforestry 92 Box 3: Farmer autonomy in a farmer network-industry 4.1.1 Government policies, land tenure, and contracts 92 partnership, Songkhla Province, Thailand 64 4.1.2 Markets, labor constraints and risk 94 Box 4: Connecting agroforestry farmer groups in 4.1.3 Finance, capital and knowledge 95 Phattalung Province, Thailand 65 4.2 Recommendations for Wider Adoption Box 5: Carbon pools and carbon dioxide 74 of Rubber Agroforestry 102 4.2.1 General recommendations 102 Box 6: Carbon units and definitions 74 4.2.1.1 Understanding stakeholder needs and aspirations 102 Table 2: Carbon stocks of different rubber systems adapted and extended from (Blagodatsky, Xu and Cadisch, 2016) 77 4.2.1.2 Government policies and support systems 103 4.2.1.3 Industry’s role 104 Table 2: Carbon stocks of different rubber systems adapted and extended from (Blagodatsky, Xu and Cadisch, 2016) 78 4.2.1.4 Researchers 105 Box 7: The complexities of soil and water mechanisms in 4.2.1.5 Farmer Networks 106 agroforestry systems 82 4.2.1.6 Collaboration 107 Table 3: Effect of different rubber intercropping systems 4.2.2 Best Practices and Pitfalls for Rubber Agroforestry 108 on soil health, as compared to monoculture rubber 83

5 Conclusions 110 Box 8: Agroforestry adoption and effect of policy reforms in Xishuangbanna, China 97 6 Methodology 112 Box 9: Differences in adoption of rubber agroforestry 6.1 Literature review 112 in northern and southern India 98 6.2 Interviews and email consultations 112 Box 10: Widespread use of intercropping in 99

7 References 113 Box 11: Multiple factors at play in farmers’ decisions to keep jungle rubber or to convert to monoculture in Indonesia 100 8 Acknowledgements 125 Box 12: Why do smallholders in southern Thailand adopt (or not adopt) rubber intercropping systems? 101

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9 Executive Summary

In this report, we assess the evidence for crease in area and tonnage, with almost 90% concerns. The clearance of natural con- whether agroforestry practices in rubber pro- produced in Asia. In addition to expansion of tributes to climate change, and exposes the duction systems could support sustainability in large-scale plantations, about 90% of supply chain, and broader society, to a the sector. Specifically, we: use existing defini- rubber is produced by smallholder farmers, who multitude of risks and harm associated with the tions of rubber agroforestry to propose a ty- are often strongly dependent on rubber tapping loss of biodiversity and natural capital. pology of rubber agroforestry systems (Section for their livelihoods. Despite livelihood and eco- 2); synthesize evidence of benefits from existing nomic benefits from growing natural rubber, In addition to these existing challenges, the agroforestry production systems for farmer research shows there are social, economic and COVID-19 pandemic is impacting global supply livelihoods, social issues, and the environment, environmental risks and harms associated with and demand dynamics that in turn affect the including biodiversity, climate change and cli- natural rubber production in monocultures. rubber supply chain down to the producer level. mate resilience (Section 3); discuss best prac- Specifically, smallholder farmers growing rubber tices, challenges, and barriers to wider adoption in monocultures are exposed to financial risk There is a clear need to improve the sustaina- of rubber agroforestry (Section 4); and make through fluctuations in the global rubber price, bility of natural rubber production. This report recommendations for achieving wider adoption because they have few alternative sources of in- facilitates sustainability initiatives for the rub- of agroforestry practices, both in the context of come when prices are low. ber sector (for example, the Global Platform smallholder farms and larger-scale plantations for Sustainable Natural Rubber, or GPSNR) by (Section 4). The degradation of soils and water in mono- providing state-of-the-art information about cultures, as well as risks to rubber health the opportunities and benefits offered by rub- Natural rubber production continues to in- from disease, drought and frost, are serious ber agroforestry systems.

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Definition of Rubber Agroforestry

There is currently no standard definition of This report uses the terms “smallholder” the term ‘rubber agroforestry’. Multiple and and “smallholdings” to refer to rubber interchangeable terms are used to describe growers who own or manage smaller plots different agroforestry systems such as: jun- of land with some degree of autonomy, in gle rubber, intercropping, or simple versus contrast to models of rubber complex rubber agroforests. Definitions of growing where larger areas of land are “agroforestry” and “rubber agroforestry” owned or managed centrally by a compa- contain two common themes: 1) a pro- ny with the use of hired labor. Strict defini- duction system from which utility can be tions of smallholdings often use a 2-hectare derived; and 2) the mixing of rubber threshold, but the relevance of size thresh- with other plants/animals (i.e. not a mono- olds varies among countries and other culture). In this report, the various forms of contextual factors. Individual cited studies agroforestry practices and systems associ- should be checked if further information ated with rubber are defined and classified about land holding size is needed. based on management intensity, complex- ity and planting design, and the terms in this classification are used throughout the report (Table ES1).

Agroforestry system integrating food crops.

Credit: CC BY 2.0 Maren Barbee

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E.S. TABLE 1 RUBBER AGROFORESTRY PRACTICES AND SYSTEMS

TYPE DESCRIPTION

Wild rubber (system) Naturally occurring rubber trees in the Amazon. May not fit the definition of “agroforestry”. At present, wild rubber extraction continues in some communities in the Amazon (including in Brazil, Peru and Bolivia) but is not a major source of production.

Traditional jungle rubber Rubber trees introduced into forests as part of swidden (i.e. slash and burn) agriculture, or via planting in thinned forest. Very (system) extensive system with very limited management and chemical inputs. Typically uses unselected (low yielding) non-clonal rubber seedlings.

Modern jungle rubber Can be the result of an abandoned or unmanaged monoculture, or a choice by farmers to adopt low intensity of management. (system) / Natural regrowth Harbors spontaneous/naturally regenerating wild species, which may be selected for their economic, medicinal, or cultural values. (practice)

Permanent intercropping Rubber trees inter-planted during or throughout the plantation cycle with one or more species with harvestable products, (system) including food and non-food crops. A wide range of species can be used, including annuals (maize, pineapple), perennials (cocoa, coffee), fruit trees (mangosteen, orange), timber trees (, ), palms, vegetables (Gnetum spp), (ginger, cardamom), and .

Temporary/short-term Light-demanding annuals/biannuals and leguminous cover crops (e.g. Flemingia macrophylla, Mucuna spp, Senna spp.) can be intercropping and cover planted in the rubber plantation in the first few years of rubber establishment. Temporary intercropping with food crops is cropping (practice) widely practiced in many countries. Cover cropping with nitrogen-fixing leguminous plants has long been promoted in plantation settings but scholars do not know the prevalence of adoption of this type of agroforestry, particularly regarding its use amongst smallholders.

Animal husbandry (practice) Animal husbandry in a rubber plot, temporary or permanent, including larger livestock (e.g. cattle, sheep – less recommended), mini livestock (bees, rabbits), poultry and aquaculture.

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Agroforestry: livelihood, social, environmental, and climate resilience effects

LIVELIHOOD OUTCOMES

INCOME DIVERSIFICATION, in Cote d’Ivoire or jungle rubber- sys- a viable strategy, particularly if additional labor ECONOMIC ANALYSIS AND tems in Kalimantan, Indonesia. is available but land is constrained. In contrast, LIVELIHOOD RESILIENCE farmers with larger holdings may prefer to di- Temporary and permanent intercropping sys- Wild rubber extraction in Latin America can con- versify their income at the farm level by plant- tems in rubber, as well as livestock farming, tribute to income of rubber tappers, but overall ing single crops separately, which may be sim- significantly contribute to smallholder in- latex yields are much lower than the global aver- pler to manage than intercropping systems. come —­ especially in very poor households age, and the wild rubber tapping industry is not Agroforestry strategies that require intensive — in Asia (Thailand, Sri Lanka, China, Philip- economically viable without subsidies. labor are unlikely to be adopted when labor pines) and Africa (Cote d’Ivoire, Liberia, Ni- is scarce. However, some agroforestry prac- geria and Gabon). Intercropping provides in- tises may actually reduce labor requirements come to both smallholders and contract farm LAND AND LABOR AVAILABILITY over time, such as reducing intensity of weed workers when rubber trees are still imma- Agroforestry systems can provide insurance removal or the use of long-term cover crops ture, and studies from Indonesia found that and flexibility during periods of low rubber price to suppress weeds, while providing addition- incorporating intercropping was a crucial fi- if they produce alternative cash crop prod- al benefits for soil and water management. nancial strategy for smallholders to support ucts or food resources. However, constraints Strategies such as the selection of species investment in replanting of rubber trees. A on land and labor availability strongly affect that require little extra labor until the option limitation for agroforestry is the unavailabil- the profitability of agroforestry practices and to harvest becomes preferable over a focus ity of local or regional markets for secondary systems for smallholder farmers. Smallholders on rubber (e.g. due to market price changes, crops, for example, in rubber-lemon systems with small plots of land may find intercropping such as in Southern Thailand), and which pro-

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vide benefits for soil and water management in come even in agroforestry systems - is con- PESTS, DISEASE AND the interim (such as in experimental systems sidered key for improving farmer livelihoods. INVASIVE SPECIES in China), could be attractive. Labor availability Using high yielding clones, optimising tapping Rubber agroforestry can be effective for reg- varies among regions: for example, labor con- strategies (e.g. ethylene gas stimulation), and ulating various harmful pests and diseases but straints are not reported in African case stud- to a lesser extent fertilizer and nutrient man- can also amplify their occurrence. Jungle rub- ies. Smallholders also often diversify income agement, are important factors to improve la- ber and intercropping help to control invasive with off-farm activities that further constrains tex yields, and continue to be vital to maintain Imperata grass in Indonesia. Anecdotally, in- their labor availability. rubber productivity in agroforestry systems. tercropping may mitigate build-up of soil dis- Shading of rubber (i.e. by taller trees) seems eases in rubber plantations, but evidence from In the case of jungle rubber in Jambi, Indone- to be the primary factor for latex yield re- China indicates that cassava intercropping sia, jungle rubber gave lower returns on land ductions in agroforestry systems, while lower can increase white disease (Rigidoporus compared to monoculture meant that many rubber planting densities result in lower total lignosus) occurrence. In Brazil, leaf-eating pest smallholders opt for the rubber or oil palm latex yield (i.e. due to there being fewer rub- mites that damage rubber trees can be con- monoculture as land is considered scarce. ber trees per hectare). However, latex yields trolled with natural biocontrol agents such as While jungle rubber gave comparable re- per rubber tree appear to be unaffected by in- fungi (e.g. Hirsutella thompsonii), which are turns on labor to rubber monoculture, neither tercropping practises. Intercropping can also more prevalent in rubber agroforests. Inter- could compete with the returns on labor for affect rubber tree growth (which affects com- cropping coffee with rubber may help reduce oil palm. In Southern Thailand, various rubber mencement of tapping time), both positively pest and disease damage in coffee by increas- agroforestry systems gave the same or greater and negatively depending on the intercrop/ ing shade, compared to coffee monocultures returns to labor compared to monoculture, but country. The shade from mature rubber, in under full sun. some agroforestry systems gave lower returns turn, typically reduces intercrop yields but ba- to land. Rubber intercropping with fruit and nana in particular seems to benefit from being timber trees gave the greatest returns to both intercropped with rubber. Yield trade-offs may FOOD SECURITY AND NUTRITION land and labor in this case. be balanced out by an overall gain when the Food insecurity and malnutrition is still a yields from rubber and intercrops are com- major problem across the globe. While food bined, or by increasing the planting density of security and nutrition issues are strongly re- RUBBER AND INTERCROP YIELDS intercrops (e.g. , banana). gion and context dependent, and require sub- Improving rubber yields - the bulk of cash in-

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stantial improvements across the entire food the food they need from market. Very few agroforestry were used to supplement house- supply chain, agroforestry can be part of the studies examined the relationship between hold food consumption, but also indirectly as multi-stranded strategy to improve food se- rubber agroforestry and food security – one a source of cash income for purchasing food curity and nutrition. This may be by directly study (from Liberia) found that agroforest- (sometimes to mitigate the loss of the com- increasing the availability and dietary diversity ry (including rubber agroforestry) improves munity’s access to forest resources for food of food by intercropping and/or integration of household food security, while other studies and income). animal husbandry, or by increasing the cash in- (mostly from Asia, one from Nigeria) found come of farmers such that they can purchase that food crops and livestock from rubber

SOCIAL OUTCOMES

GENDER for female participation, because it requires LAND TENURE Gender issues in agroforestry systems are im- more family labor, although in some cases In some countries, agroforestry involving per- portant to consider, because in many societies (such as Southern Thailand) women may al- manent or long-lived crops, like rubber trees, women and men have distinct roles and pref- ready be strongly involved in rubber tapping can improve land tenure security compared erences, for instance in land-use decision mak- alongside other responsibilities and as such to annual crops alone for smallholder farmers, ing, divisions in domestic, farm and off-farm would be burdened by additional demands because facilitated claims of own- labor, tree planting, and participation in rural for family labor. Rubber agroforestry strate- ership and longer tenure durations by farmers. value chains. However, information on gender gies can be tailored to local gender roles and In countries where rubber is classified as an equity and labor burdens specifically in rubber cultural preferences to increase female inter- agricultural crop and not timber, intercrop- agroforestry systems is still limited. Overall, est and participation in agroforestry, such as ping rubber with timber can increase duration both men and women are involved in rubber women-led trainings and intercropping with of land tenure, because some national policies farming and tapping (both monoculture and medicinal plants (which may be associated grant longer leases of land for than for agroforestry) in Southern China, Thailand, with women’s roles in some cultures) that agriculture. However, some smallholders may Malaysia, and Indonesia. However, rubber could offer additional benefits, including cash want to leave farming and, prefer shorter term agroforestry could create more opportunities income, for underrepresented groups. or annual crops over timber trees that will not

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tie them to the land. There is also a risk that OTHER SOCIOCULTURAL BENEFITS others. These networks have also increased without suitable tenure and Farmers in Southern Thailand reported social farmer knowledge about rubber processing policies in place, agroforestry may incentivize benefits from rubber agroforestry practices, and assessment, enabling them to cut out mid- forest conversion into agroforestry plots. including knowledge transfer, feelings of au- dlemen in the supply chain and receive a price tonomy, and social benefits from harvesting premium, in addition to enabling farmers to edible species to e.g. provide fruits as gifts to share knowledge and participate in research by universities about intercropping practises.

ENVIRONMENTAL OUTCOMES

CLIMATE RESILIENCE OF plants in intercropping systems, while inter- CLIMATE MITIGATION THROUGH AGROFORESTRY crops can improve soil water retention across CARBON SEQUESTRATION Climate change is exacerbating existing risks the whole system, although outcomes for wid- The carbon stock of a rubber plantation, or facing rubber production, particularly in mar- er-scale hydrology are unclear. Smallholder agroforest, is more difficult to measure than it ginal areas. As evidence on climate resilience rubber farmers from Thailand and the Philip- may appear, because the long-term destiny of on rubber agroforestry is limited, drawing pines report concerns around climate change the carbon stored in trees in any system must a simple conclusion is difficult. It is known, and consider agroforestry as an adaptation or be considered. Specifically, it is important to however, that water use of rubber cultivation mitigation strategy. There is some evidence understand the fate of trees at the end of a systems is of considerable concern, because that rubber agroforestry can buffer the ef- plantation cycle, and the importance of contin- rubber is planted often in locations with long fects of normal fluctuations in microclimate, uous latex extraction. For rubber monocultures dry seasons, increasing the risk of climate-re- but there is currently little evidence that they in Southeast Asia, a robust time-averaged car- lated drought events. Rubber trees have been could do so during climate change-induced ex- bon stock estimate for rubber is 52.5 tonnes of shown to adapt their and water use treme weather events. carbon per hectare, lower than that of natural patterns to minimise competition with other forests of any type (including dry deciduous

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forest in Cambodia) but greater than that of SOIL HEALTH AND WATER imising herbicide application to once per year annual crops. MANAGEMENT could substantially reduce soil loss relative to There is evidence from China (Xishuangbanna more regular weeding. Incorporation of additional plant species into and Hainan Island) for long-term declines in rubber systems will increase above-ground bio- soil fertility with repeated cultivation of rub- mass, and therefore increase carbon storage in ber monocultures. Soil nutrient reserves can ECOSYSTEM RESILIENCE AND agroforestry systems. Following evidence from become depleted in monocultures due to soil BIODIVERSITY cocoa and coffee systems, agroforestry can erosion, mineralization of soil organic matter Ecosystem resilience and biodiversity benefits increase carbon storage, reduce greenhouse (SOM), and nutrient export with rubber tap- of rubber agroforestry depend strongly on gas emissions and therefore mitigate climate ping. There is, hence, a need for better soil and the type of agroforestry. Wild tapped rubber change effects. nutrient management in rubber plantations. A from trees growing naturally in the Amazon substantial body of evidence shows the benefits is unique in that it is sourced from a natural The net carbon outcomes of rubber plantation of permanent intercropping and jungle rubber ecosystem, and like cocoa-rubber or agroforestry establishment, from the per- agroforestry for enhanced soil carbon, soil nu- agroforestry, these systems provided wildlife spective of land cover change, strongly depend trients, reduced water runoff and soil erosion, habitat for e.g. endangered golden lion-head- on the former land cover. While strongly con- improved soil structure, increased water infil- ed tamarins. Jungle rubber is the most struc- text and tree density dependent, rubber carbon tration into soils, complementary water use turally diverse agroforestry system that con- balances showed that when considering mono- between rubber and intercrops, reduced soil tains multiple tree species and supports great- culture rubber plantations, net carbon seques- acidity and enhanced soil microbial biodiversity. er biodiversity than a monoculture plantation. tration (draw-down) occurs after conversion of However, much of this evidence needs further Permanent intercropping systems of fruit, arable land to rubber plantations, but carbon strengthening with repeated larger-scale stud- palms, timber or vegetables contain more spe- emissions (losses) occur if natural forest is con- ies that also capture the strong variation in soil cies of fruit-feeding butterflies, but had similar verted to rubber. Therefore, clearance of natu- properties between individual farms. There is no numbers of reptile and bird species than mon- ral forest, or permanent jungle rubber agrofor- evidence for nutrient competition between rub- ocultures. Fruit agroforests in Indonesia can estry systems (that are not felled on a cyclical ber trees and intercrops, and mixed evidence support orangutans (but at a cost to farmers basis) will always have a net negative impact on with legume cover crops. Unrelated to agrofor- who lose fruit crops, which may require com- carbon emissions and climate change. estry, terracing protects some organic carbon pensation). Bird species richness was greater from losses during rubber development. Min- in rubber plots that had more understory veg-

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etation independent of any intercrops. Con- species (which provide a variety of ecosystem such as rubber agroforestry benefit biodiversi- servation priority and forest-dependent birds services such as pest control), but crucially ty and can maintain biodiversity by connecting were not supported within rubber agroforests. they contained fewer invasive ant species than natural habitat patches. Agroforests contained similar numbers of ant monocultures. In general, diversified systems

Barriers to Adoption of Rubber Agroforestry

Implementation of agroforestry production is sufficient income from rubber monoculture or markets for intercrops was also cited as a bar- hindered by various factors. Outgrower con- alternative sources of income, especially when rier to agroforestry. As the rubber agroforestry tracts for smallholders provided by rubber rubber prices are high, they do not see a need model is still rare in most countries (although companies guide production methods and can to practice agroforestry, which would require a rough estimate suggests 60% of rubber cul- limit the option to implement agroforestry an increase in management complexity, includ- tivation in Indonesia comes from jungle rubber practices. Government policies favoring mono- ing additional knowledge/expertise and labor. systems), smallholders and industrial planta- cultures can strongly influence the adoption of However, labor shortages are a common barrier tions accustomed to the monoculture model rubber agroforestry practices. Lack of land or to implementing agroforestry, as in many rural are likely to be risk averse and stick to existing tree tenure security also determines whether areas of rubber-producing regions economic strategies. The lack of technical knowledge and smallholders are willing to invest in longer-term development and urban immigration have re- theft of intercrops was also perceived to be a agroforestry systems. If smallholders receive duced rural labor availability. Lack of access to problem for smallholders.

Recommendations

In general, it is essential to understand the for agroforestry models and best practices will and nutrition, gender equity, and the environ- needs, constraints, and interests of smallholders need to be tailored to the diverse contexts in ment. There is also a need for better dissem- and plantation managers to effectively imple- the producer countries and regions to produce ination of information about the benefits of ment rubber agroforestry. Recommendations the best outcomes for livelihoods, food security agroforestry to local audiences — in particular,

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that there are no yield declines compared to RUBBER INDUSTRY adoption of rubber eco-certification that grant monoculture systems. Industrial and large-estate plantations should a price premium for smallholders and industrial embrace additional indicators of sustainabil- growers who implement agroforestry and oth- GOVERNMENT POLICIES ity around livelihoods, soils, biodiversity and er sustainable practices. Specifically, government policies are needed climate resilience, and recognize that agrofor- to promote agroforestry practices that have estry practices and systems can be a financially demonstrated environmental and climate ben- viable strategy towards sustainable production. NON-INDUSTRY ACTORS efits and to discourage unsustainable farm Plantation companies should invest in research Researchers can support smallholder farmers management (e.g. unnecessary herbicide spray- and development to identify cost-effective with well-evidenced agroforestry knowledge, by ing on large areas of rubber plantations). These agroforestry practices to be published in their co-developing best practices and help to iden- policies need to be consistent and persistent, sustainability reports. Agroforestry practices tify farmers’ challenges. Researchers should account for land-use planning, land tenure to be considered include reduced herbicide aim to co-develop research where possible, policies, avoid detrimental environmental im- application; cover cropping; intercropping with and share their research findings with rubber pacts, and support smallholders’ investments. crops that require little maintenance; planting research institutes, civil society organizations In new rubber development frontiers, rubber of riparian areas with diverse native species; (CSOs), and the farmer networks and co-oper- agroforestry models should be encouraged and and temporary intercropping between rub- atives they work with, to ensure knowledge is subsidized as an alternative to monoculture ber rows during the first three years of rubber available to those who can apply it. Researchers plantations. Farmer-to-farmer communication establishment. Plantation companies can tri- can help uplift farmer produced knowledge and networks should be actively supported and al rubber agroforestry practices on a portion personal experiences by highlighting those in developed, so that Indigenous and smallholder of their estates, support rubber agroforestry their work, and particularly in situations and cul- farmer knowledge and traditions are sustained, among smallholders via outgrower schemes, tures where published or accredited research is food security and nutrition is ensured, and male provide access to parts of the plantation for perceived as having high value and credibility. and female farmers have flexibility to meet their rubber workers or their families to intercrop, Our literature review has also highlighted a ma- own needs. We also discuss the need for several and facilitate knowledge exchange. Rubber buy- jor research gap in regards to published studies support systems including the dissemination of ers, such as companies, should facilitate on rubber agroforestry and food security and technical recommendations via extension ser- the adoption of agroforestry rubber by creat- nutrition, gender equity and labor burdens, land vices and demonstration plots or model farms. ing a demand for agroforestry rubber through tenure, and other social dimensions (e.g. farmer procurement policies, and/or by facilitating the empowerment, food sovereignty).

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SMALLHOLDER FARMERS In summary, there is a need for collaboration summarize best practices for rubber agro- Farmer-to-farmer networks and associations between multiple stakeholders to make cultur- forestry because they are highly context de- facilitate the spread of agroforestry practices al shifts to agroforestry, from smallholders and pendent. Similarly, pitfalls occur when these and knowledge in farming communities. Farm- estate companies to government policies. There context-dependent factors are not considered er networks and co-operatives provide mutu- should be a multi-way exchange of information implementing rubber agroforestry practices. al support and more opportunities for people regarding agroforestry best practices among Effective agroforestry practices or systems to gain access to knowledge, regardless of and between smallholder farmer networks, re- should account for constraints, including the gender, as well as skills and resources via col- searchers, CSOs and industry. Agroforestry re- local biophysical environment, market availa- lective action. However, the effectiveness of searchers should consolidate the global and lo- bility, male and female smallholder needs and collaborative networks between stakeholders cal knowledge base of agroforestry and promote constraints, and the objectives of implement- to address environmental problems is often best practices. Input from industry, in terms of ing agroforestry. hindered by individuals fearing that their hard- both agroforestry best practices and agroforest- earned knowledge will be exploited and they ry value chain development is another piece of While this report does not provide a list of tech- do not stand to gain from the networks, differ- the puzzle. Input from real farmers are necessary nical recommendations because of the diver- ences in knowledge gaps between participants, to ensure effective implementation. An agrofor- sity of factors and situations, some strategies and whether such issues can be overcome in a estry-oriented innovation platform was suggest- for avoiding reduction in rubber yields and in- foreseeable time period. In Southern Thailand, ed to facilitate such collaboration and informa- creasing productivity in intercropping systems rubber agroforest smallholder farmers have tion exchange. Funding or support from the UN, have been established by prior research. These formed groups around common interests, key climate change agencies and rubber buyers include: double-row alley cropping with wider which have facilitated the spread of agrofor- could help to facilitate this. interspacing for intercrops, not planting trees estry among peers as well as collaboration with that would shade out rubber, and not planting researchers and industry. There are no universal best practices for agro- intercrops in the rubber line. forestry, and experts found it challenging to

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Conclusion

Rubber agroforestry systems are dynamic and and techniques but have found it not to be lost, such as Indonesia, to inform rubber sus- versatile, consisting of multiple components widely adopted. This may not indicate that rub- tainability efforts now. Similarly, there is much that make contributions to smallholder live- ber agroforestry itself is untenable, because potential for plantation companies to benefit lihoods, food security and nutrition, provide ample evidence suggests that rubber yields in from implementing agroforestry practices on social advantages, and improvements for soils, intercropping systems are no lower than mon- estates, and rubber buyers play a crucial role water and other environmental and climate ocultures, while income risk is more diversified in facilitating demand and developing value outcomes. Research gaps still exist around the in agroforestry systems. Instead, this shows chains for agroforestry rubber. ‘best’ practices for agroforestry such as ap- that farmers may not have had access to the propriate intercrops, optimal tree spacing, and information, capital or physical inputs (e.g. Overall, creating an environment where farm- water usage; as well as the social outcomes of seedlings) needed to diversify in the first place, ers have access to knowledge, information, agroforestry such as gender, food security and that policy or market conditions were not right capital, markets and importantly, the autonomy sovereignty, and nutrition. Better information for agroforestry to work more widely, or that to choose which components of agroforestry sharing is needed, for example through farm- farmers’ preferences and motivations were not best suit their needs and constraints would al- er-to-farmer exchanges, the opening up of rub- well understood. Rubber is a long-term invest- low them to exercise creativity and sovereignty ber research institute reports and knowledge ment but has short term price volatility. Les- in their farms and livelihoods. In the UN Decade into the public domain, and better translation sons must be learned from places where rub- of Restoration, learning from existing and taking of scientific studies into user-friendly materials ber cultivation has generated long-term bene- on the challenge to establish new agroforestry for use by government agencies and businesses. fits for farmers and where agroforestry prac- systems has the potential to make a substantial tices are reaping rewards for farmers, such as contribution to bring sustainable improvements Multiple projects have trialled rubber agrofor- in Southern Thailand or China, as well as places to the environment and farming livelihoods, if all estry practices with modern rubber varieties where existing agroforestry practices are being stakeholders unite to build a better tomorrow. May, 2021

16 RUBBER AGROFORESTRY Introduction

1 Introduction

1.1 THE CURRENT STATE OF THE RUBBER INDUSTRY

Natural rubber production continues et al., 2020)), who are often strongly to increase in area and tonnage. In dependent on rubber tapping for their 2019, 12.3 million hectares of rubber livelihoods. Large-scale plantations were grown globally, an increase of 3 are also continuing to be productive million since 2009, while production and to expand in area. increased by 4.3 million tonnes over the same 10-year period (FAO, 2021). Increasing attention is being paid to Eighty-nine percent of this rubber the social, economic and environ- area, and 88% of tonnage, was pro- mental sustainability of natural rub- duced in Asia. About 90% of natural ber production, particularly focussed rubber is produced by smallholder on the risks associated with mono- farmers ((IRSG, 2019) as cited in (Gitz culture plantations (Warren-Thom- as, Dolman and Edwards, 2015). Smallholder farmers dependent on A worker on a rubber rubber are exposed to financial risk plantation, Indonesia. through fluctuations in the global Credit: CC BY-NC-ND 2.0 Tri Saputro/CIFOR

17 RUBBER AGROFORESTRY Introduction

rubber price, threatening their livelihoods Given these concerns, sustainability initia- holders who rely on rubber tapping will not and the social and economic sustainability tives are now underway for the rubber sector, necessarily cease production even if prices of production. The degradation of soils and including the Global Platform for Sustainable fall), and crude oil prices (Miller, 2020). water in monocultures, particularly those Natural Rubber (GPSNR), the Internation- grown on steeper slopes, is a serious con- al Rubber Study Group’s Sustainable Natu- In addition to these existing challenges, the cern (e.g. Ziegler, Fox and Xu, 2009; Jiang et ral Rubber Initiative (which recently signed Covid-19 pandemic is affecting many aspects al., 2017), while newer plantations in more an MOU with the GPSNR (GPSNR, 2019)), of the rubber supply chain, and the people who marginal areas are increasingly exposed to Fair Rubber eV certification, and many oth- produce natural rubber. In early 2020, the As- risks of disease, drought and cold (Ahrends er “eco-certification” measures (Kennedy, sociation of Natural Rubber Producing Coun- et al., 2015). Meanwhile, the clearance of Leimona and Yi, 2017). These initiatives set natural forests that store more carbon than out criteria or visions for multiple aspects of plantations contributes to climate change, sustainability. “The clearance of natural and exposes the rubber supply chain, and forests that store more carbon broader society, to a multitude of risks asso- The effect of fluctuating rubber prices is of ciated with the loss of biodiversity, habitats fundamental importance to the sustainability than plantations contributes and natural capital (Warren-Thomas, Dol- of rubber production. Fluctuations in rubber to climate change, and exposes man and Edwards, 2015; Warren-Thomas et prices are of serious and direct consequence al., 2018). Increasing attention is therefore for smallholder farmers, particularly those the rubber supply chain…to a being paid to multiple aspects of sustain- who grow rubber in monocultures, and those multitude of risks.” ability in the rubber sector, which is made who have few alternative sources of income complicated by the long and complex sup- or access to adequate food and nutrition. ply chains connecting smallholder farmers Price variation strongly impacts livelihoods tries (ANRPC) forecasted increases in produc- to buyers (Kennedy, Leimona and Yi, 2017). and drives farmer choices about manage- tion and demand of 3.8% and 2.7% respective- Meanwhile, some large-scale plantations and ment and production. Prices are influenced ly, but later suggested an overall contraction in supportive outgrower contracts offer oppor- by seasonal fluctuations, supply and demand production for 2020 (reductions of 4.7% and tunities to rapidly scale-up sustainable culti- (which is difficult to predict due to time lags 6% respectively) (Zengkun, 2021). Demand vation practices to large areas of production. from planting to production, the possibility from auto and tire industries has reduced, of storage and stockpiling, and because small- while increases in demand for other rubber

18 RUBBER AGROFORESTRY Introduction

products, such as personal protective equip- holders more vulnerable than ever (Zeng- ment (PPE), have not been large enough to kun, 2021). Despite the challenges, and espe- offset reductions (Miller, 2020). Future fore- cially because of the climate emergency, there casts are likely to be very uncertain (Gitz et al., is therefore a clear need to push ahead with 2020). The pandemic has also affected sup- efforts to improve the sustainability of natural ply chains, the operations of plantations, rubber production, and particularly to support and the roll-out of sustainability initiatives smallholder rubber producer livelihoods. and farmer support, making rubber small-

1.2 SCOPE OF THE REPORT

In this report, we assess the evidence for how wider environment, including climate agroforestry practices in rubber production change and climate resilient production; systems could support sustainability in the • Last, we discuss best practices, challenges sector, as broadly-defined above. and barriers to wider adoption of rubber agroforestry, and make recommendations • First, we examine the definition of rubber how wider adoption could be achieved, agroforestry and propose a typology of both in the context of smallholder farms rubber agroforestry systems; and larger-scale plantations. • Second, we synthesize evidence of benefits from existing agroforestry production systems for smallholder farmer livelihoods, social issues and the

An agroforestry system intercropping rubber with cassava, Cambodia. Credit: CC BY-NC-ND 2.0 Neil Palmer / CIAT

19 RUBBER AGROFORESTRY Introduction

In this report, 2 Definition of rubber we would like agroforestry to emphasize

agroforestry for 2.1 DEFINITION AND PROPOSED livlihoods, which TYPOLOGY FOR RUBBER unites agronomic, AGROFORESTRY Agroforestry has been defined as “a (e.g. with the goal of maximising crop environmental as collective name for land-use systems production on the same land), envi- and technologies in which woody per- ronmentally oriented (e.g. with the well as sociocultural ennials are deliberately grown on the goal of making agricultural landscapes same piece of land as agricultural crops closer to natural forest ecosystems), concerns.” and/or animals, either in some form of and/or livelihoods oriented (e.g. with spatial arrangement or in sequence. In the goal of diversifying smallholder agroforestry systems, the woody com- production for better social, econom- ponent interacts ecologically and eco- ic and environmental outcomes) (So- nomically with the crop and/or animal marriba, 1992; Leakey, 1996). components” (Lundgren, 1982). Agro- forestry can be agronomically oriented In this report, we would like to em-

20 RUBBER AGROFORESTRY Introduction

phasize agroforestry for livelihoods, sively-managed complex assemblages which unites agronomic, environmen- of rubber trees in tal as well as sociocultural concerns.1 fallows, to production-driven simple inter-plantings of timber species with There is currently no standard defi- clonal rubber trees. Moreover, there nition for ‘rubber agroforestry’ in the are multiple, interchangeable terms sector, which is also the case for co- used to describe different agroforest- coa agroforestry (Sanial et al., 2020). ry systems, including jungle rubber, In the literature, the term “rubber rubber gardens, intercropping, mixed agroforest” has been used to describe cropping, and simple vs complex rub- widely different systems, from exten- ber agroforests.

Harvesting cinnamon, Indonesia. Credit: CC BY-NC 4.0 Tri Saputro/CIFOR

1 A livelihoods-oriented definition is currently used by ICRAF: “Agroforestry is a dynamic, ecologically based, natural resource management system that, through the integration of trees on farms and in the agricultural landscape, diversifies and sustains smallholder production for increased social, economic and environmental benefits” (Leakey, 1996).

21 RUBBER AGROFORESTRY Introduction

BOX 1 SOME EXAMPLES OF DEFINITIONS OF RUBBER AGROFORESTRY, FROM INTERVIEWS AND EMAIL CONSULTATIONS WITH RUBBER EXPERTS

“Permanent crops mixed with rubber; “Agroforestry refers to tree culture “The definition of rubber agroforest- not annuals.” that incorporates other crops, whether ry should not include diversified farms trees, shrubs and/or annuals, and ani- including rubber trees grown separately mal husbandry/aquaculture in order to to other crops or livestock (but that are “An agriculture system, where you manage have resemblance of a typical forest. The technically part of the same farm), nor rubber trees within the forest.” crops (trees, shrubs and annuals) and be used to describe rubber farms that the animal components of agroforestry have no secondary crops but that contain “The mixing of rubber with long-lived have economic value for food, fibre and substantial understory vegetation. These plants and animals. Rubber is the main the industry. Types of agroforestry de- could be termed “wildlife-friendly” or trees in the farm.” pend on the objective of the agroforestry similar, instead. Rubber farms with short practice.” term inter-cropping during the immature rubber phase, but which revert to mono- “Modern rubber agroforestry is planting culture once trees are mature, should rubber as key crop in a more intensive “Agroforestry is a forest created by man also be considered distinct from mature pattern, intercropping with other plants (people), mixing different small crops for rubber agroforests.” 2 and maybe livestock.” the local producer to have some profit.”

“In general, rubber agroforestry refers to “Diversified production system in which rubber grown with other species, but it rubber trees are among other crops and can vary depending on how much plan- timber and non-timber forest products.” ning is involved.”

2 Eleanor Warren-Thomas, based on (Warren-Thomas et al., 2020)

22 RUBBER AGROFORESTRY Introduction

The interchangeability and ambiguity of rubber on whether practices such as cover cropping, estry systems vary by: agroforestry terms, the context-dependence of temporary intercropping with annuals during agroforestry studies, as well as confusion over the first few years of rubber establishment, or • Management intensity, including the the different types of agroforestry systems and simply allowing natural regrowth in rubber choice of rubber planting material practices, has made it challenging to assess the monoculture plantations could or should be • Complexity, including the number of evidence for the potential benefits of scaling considered “rubber agroforestry”. While in- species; structural complexity of the up rubber agroforestry practices, as well as corporating these agroforestry practices into vegetation; and temporal scales recommendations for best practices. In addi- a rubber monoculture can bring environmen- tion, rubber productivity, or latex yields, are tal, social and economic benefits, doing so • Planting design, including spacing of strongly influenced by multiple factors unre- does not necessarily turn a monoculture into rubber rows and planting density lated to agroforestry practices (e.g. quality of an ‘agroforest’ (Table 1). rubber planting material, planting density, tap- ping frequency), making comparisons among As a step towards clarifying and defining rub- Given the ambiguity and fluidity of the term different studies challenging. ber agroforestry, we have attempted to define ‘agroforest’, we have deliberately avoided us- and classify the various forms of agroforestry ing this term in our classification scheme, but Definitions of “agroforestry” and “rubber practices and systems associated with rubber, in the rest of the report we use it as a general agroforestry” varied among experts and stake- as compiled from the literature and expert term to refer to any of the categories speci- holders interviewed for this report (Main re- consultations (Table 1: Rubber agroforestry fied below. We acknowledge that no typology port), but two common themes were: (1) it is practices and systems). We have only consid- is perfect, but we hope that this will provide a production system from which utility can be ered systems involving the Pará rubber tree a useful and comprehensive guide towards a derived; and involves (2) the mixing of rub- ( Müll.Arg.), but there may better understanding of rubber agroforestry ber trees with other plants/animals (i.e. not be agroforestry systems associated with other practices and systems. a monoculture). However, opinions varied latex-producing trees/plants. Rubber agrofor-

23 RUBBER AGROFORESTRY Introduction

TABLE 1 RUBBER AGROFORESTRY PRACTICES AND SYSTEMS

A proposed typology of rubber agroforestry systems (wild rubber, jungle rubber, permanent intercropping), and agroforestry practices (temporary intercropping, allowing natural regrowth, animal husbandry) that can be implemented in rubber plantations, synthesized from the literature and expert consultations. These practices can be combined with each other and with agroforestry systems (e.g. cover cropping + animal husbandry; temporary intercropping + permanent intercropping + animal husbandry). We have drawn heavily from previously published classification schemes, including Langenberger et al. (2017) and Stroesser et al. (2018). A more detailed discussion of systems follows in the text.

CC BY-NC 4.0 EWT – Peru CC BY-NC 2.0 Tri Saputro/CIFOR CC BY-NC 4.0 MWMH – Malaysia

WILD RUBBER (System) TRADITIONAL JUNGLE RUBBER (System) MODERN JUNGLE RUBBER (System) / Naturally occurring rubber trees in forest set- Rubber trees introduced into forests as part of NATURAL REGROWTH (Practice) tings. May not fit the definition of “agrofor- swidden agriculture, or via planting in thinned Starts off as a monoculture using clonal rub- estry”. At present, wild rubber extraction con- forest. Very extensive system with very limited ber, but spontaneous/natural regrowth of wild tinues in some communities in the Amazon management and inputs. Typically uses unse- shrubs and trees make it resemble a “tradi- (including in Brazil, Peru and Bolivia) but is not lected (low-yielding) non-clonal rubber seed- tional” jungle rubber. Usually a result of being a major source of latex production. lings. Rubber trees of different ages in perma- abandoned or left unmanaged for some time, nent/sisipan systems in Indonesia. or can be a deliberate choice by farmers, par- ticularly the most experienced. Limited man- agement, but naturally regenerating species may be selected for their economic, medicinal or cultural values.

24 RUBBER AGROFORESTRY Introduction TABLE 1 (CONTINUED)

CC BY-NC 4.0 TCW - Myanmar CC BY-NC 4.0 EWT – Thailand CC BY-NC 4.0 EWT - Thailand

PERMANENT INTERCROPPING (System) TEMPORARY/SHORT-TERM INTERCROP- ANIMAL HUSBANDRY (Practice, but can be Rubber trees inter-planted during or throughout PING AND COVER CROPPING (Practice, but considered agroforestry system if perma- the plantation cycle with one or more species with can be considered agroforestry system if nently integrated) harvestable products, including food and non- permanently integrated) In Thailand, stingless beekeeping was highlighted food crops. A wide range of species can be used, Light-demanding annuals/biannuals and leguminous as a successful example,3 and some farmers kept including annuals (cassava, maize, pineapple, soy cover crops (e.g. Mucuna spp, Senna spp.) can be cows, poultry, swine, goat and sheep in immature bean), perennials (cocoa, coffee), fruit trees (man- planted in the rubber plantation in the first few and mature plantations (Somboonsuke et al., 2011). gosteen, orange), timber trees (teak, mahogany), years of rubber establishment, usually up to three In Malaysia, some research on sheep and other ani- palms, spices (ginger, cardamom), and mushrooms. years (“light phase” in the classification of Langen- mal husbandry in rubber plantations has been con- berger et al (2017)). Temporary intercropping with ducted by research institutes (Tajuddin, 1986; Jusoff, food crops widely practiced by smallholders in many 1988; Chong et al., 1997). In Vietnam, rubber trees countries, and even in industrial plantations under are incorporated into local integrated agroforestry contract farming systems, e.g. in Laos (Hicks et al., systems (“garden-pond-cage-forest”), consisting of 2009). Cover cropping with leguminous plants (ni- forest trees + fruits + annuals + aquaculture + ani- trogen-fixing) has long been promoted in plantation mal husbandry (Sen, 2015). In Nigeria, mini-livestock settings but unsure how widely adopted in rubber, (bees, stingless bees, rabbits, snails) and aquaculture especially among smallholders (Langenberger et are used on rubber farms (Mesike, Esekhade and al., 2017). Used to reduce erosion, increase soil nu- Idoko, 2019). In Cameroon, chickens, pigs and fish trients, for weed control (e.g. Imperata dominated were kept in years 4-7 of rubber plantation cycle.4 systems in Indonesia), and provide fodder (Langen- Larger livestock such as cattle typically not recom- berger et al., 2017). The use of cover crops that do mended (cattle can damage trees or latex collection not produce a secondary product that can be con- cups), but smaller species such as bees were noted sumed/sold would not usually be termed an agro- as successful cases. forestry practice, unless combined with other crops.

3 Interviews, Sara Bumrungsri, Uraiwan Tongkaemkaew, and Michael B. Commons. 4 Corrie-Maccoll, 2020. Overview: The Cameroon Outgrower Programme. Website: https://www.corrie-maccoll.com/cameroon-outgrower-programme-overview/ 25 RUBBER AGROFORESTRY Introduction

INTEGRATING MULTIPLE CROPS Rubber agroforestry can provide many benefits to farmers.

Rubber agroforesty is defined by the existence of multiple types of crops or livestock in one farm system, providing income and/or subsistence to farmers. These farms can be planned to best meet the needs of the climate, geography, and community.

A model agroforestry rubber forest garden, incorporating animal husbandry. Kittitornkool, J et al (2019)

26 RUBBER AGROFORESTRY Introduction

2.2 WILD RUBBER

One special case of a rubber system that tractive reserves were conceived to provide Associated terms: wild rubber; native rub- could be termed “agroforestry” is wild or na- land tenure rights for forest-based commu- ber; extractivism; rubber tapper. tive rubber in South America. The rubber tree nities while also conserving livelihoods based (Hevea brasiliensis) and related Hevea species on sustainable forest use (Wallace, Gomes Management intensity: Little management, are native to the forests of South America. and Cooper, 2018). In northern Bolivia, wild wild rubber trees are allowed to grow natural- Native rubber was used traditionally by In- rubber tapping, linked to a debt-patronage ly in the rainforest. digenous communities in the Amazon. Wild system, was a significant part of economic ac- rubber extraction in the Amazon became tivity up until its decline the early 1990s (Ro- Complexity: Highly complex in structure and an important industry during the late 1800s manoff, 1992; Stoian, 2000). species, as wild rubber trees grow naturally in and early 1900s, and again during WWII; se- the rainforest. rious social impacts and human rights vio- At present, wild rubber extraction continues lations, for indigenous communities as well in some communities in the Amazon (includ- Planting design: Wild rubber trees are ran- as for migrant labor brought in to tap rubber ing in Brazil, Peru and Bolivia) but is not a domly dispersed (as opposed to clustered), trees, were widespread (Brown and Rosendo, major source of latex production (WWF-UK, and tree density ranges from 0 to 4 trees/ha 2000; Stoian, 2000; Gomes, Vadjunec and 2014; WWF Brasil, 2015; Fitts, Cruz­-Burga (average = 1.67 trees/ha) (Jaramillo-Giraldo et Perz, 2012; Fitts, Cruz­-Burga and La Torre­- and La Torre-Cuadros,­ 2020). Some individu- al., 2017). -Cuadros, 2020). In the 1970s-1980s, the Bra- als still identify with their traditional cultural zilian “rubber tappers” social movement from identity as a “rubber tapper”, but it does not Example locations: Brazil (particularly the Acre, Brazil, gained international prominence necessarily reflect their economic activity, states of Acre and Rondonia); Peru; Bolivia. and became intertwined with environmen- nor do they always see themselves as “envi- talism, leading to the creation of “extractive ronmental defenders”5 (Gomes, Vadjunec and reserves” in Brazil (Keck, 1995). These ex- Perz, 2012).

5 Interview, anonymous researcher

27 RUBBER AGROFORESTRY Introduction

2.3 TRADITIONAL JUNGLE RUBBER

“Jungle rubber” is a term used in the litera- ing rubber seedlings in forest gaps, or al- in Jambi, West Sumatra and West Kalimantan, ture to refer to traditional rubber agroforest- lowing spontaneous regeneration from to try and encourage maintenance of jungle ry systems found in Indonesia, where rubber rubber seeds (Wibawa, Hendratno and van rubber systems (Penot and Ari, 2019). They trees were introduced into forests as part of Noordwijk, 2005). tested the potential for enrichment planting swidden agriculture cycles (slash and burn of seedlings or grafted-clonal rubber plants systems), or via permanent gap-planting in Traditional jungle rubber was historically a in jungle rubber to improve latex yields and secondary forest (“sisipan” system) (Wibawa, widespread practice in Southeast Asia,6 but income, as well as different spatial arrange- Hendratno and van Noordwijk, 2005; Vincent is now mostly confined to the Indonesian ments of intercropping and species (Wil- et al., 2011). This type of rubber agroforestry islands of Sumatra and Kalimantan (Joshi et liams et al., 2001; Wibawa et al., 2006; Vincent system arose from people introducing rub- al., 2003). Even here, traditional jungle rub- et al., 2011; Penot and Ari, 2019). However, ber trees into their traditional swidden-based ber systems are increasingly being converted switching to clonal rubber plants led farmers practices (Feintrenie and to intensively managed rubber and oil palm to intensify management, making it closer to Levang, 2009), and are characterized by be- monocultures, which provide greater income a typical plantation than a traditional jungle ing extensive systems with very limited (Ekadinata and Vincent, 2011; Clough et al., rubber system (Williams et al., 2001). These management and inputs, which typically 2016). This type of rubber agroforestry sys- cases of clonal rubber planted in forest plots use unselected (i.e. low yielding) non-clon- tem has received considerable research atten- al rubber seedlings. These systems are tion due to its potential for conserving bio- species rich and structurally complex as diversity, and maintaining forest connectivity “Traditional jungle rubber a result of natural regeneration of native between isolated remaining patches of low- systems are increasingly plants (Gouyon, de Foresta and Levang, land rainforest, while providing cash income 1993). In the permanent sisipan systems, jun- to farmers (Joshi et al., 2003). In particular, being converted to intensively gle rubber plots consist of rubber trees of the Indonesian branch of ICRAF and the In- managed rubber and oil palm different ages as smallholders maintain a donesian Rubber Research Institute set up a number of productive trees by interplant- network of demonstration and research plots monocultures.”

6 Interviews, Sara Bumrungsri and Uraiwan Tongkaemkaew.

28 RUBBER AGROFORESTRY Introduction

“may therefore be closer to the “modern” Management intensity: Variable, much low- Planting design: Highly variable, likely un- jungle rubber systems detailed below, but the er than systems using clonal rubber. planned – e.g. Gouyon (1993) found rubber variety of rubber agroforest systems in prac- tree densities ranging from 200 trees/ha (40- tice defy neat categorisations into any strict Complexity: High structural, functional, and 45 year old plot in Jambi) to 490 trees/ha (35- typology. species diversity, similar to a secondary forest. 40 year old plot in South Sumatra). May be defined by a closed canopy and a dense Associated terms: old jungle rubber; com- undergrowth layer dominated by many shrubs, Example locations: Indonesia (Kalimantan, plex rubber agroforests; rubber enriched sec- small trees, and seedlings of canopy species Jambi, North Sumatra, West Sumatra); his- ondary forests. (Gouyon, de Foresta and Levang, 1993). torically existed in Thailand and Malaysia but few remaining.

2.4 NATURAL REGROWTH / MODERN JUNGLE RUBBER

The term “jungle rubber” is also used by sometimes economic – when rubber prices ber yields. These systems have limited man- farmers, practitioners, and researchers7 to are low, smallholders may find that it is not agement (i.e. receiving little or no fertiliza- refer to rubber agroforests that start off as worth tapping/maintaining rubber trees and tion or weeding), but naturally regenerating a typical monoculture, but are left unman- switch to other more profitable livelihood species may be selected for their economic aged for some time, and the resulting nat- sources. Alternatively, in some cases more value, as some smallholders have done in ural regrowth of shrubs and trees make it experienced rubber growers prefer to leave Thailand.8 Allowing natural regeneration in resemble traditional jungle rubber or a sec- inter-row vegetation to develop naturally, rubber monoculture plantations may have ondary forest. Reasons for such rubber areas understanding that this does not affect rub- environmental, livelihoods and sociocultural

7 Interviews, Gerhard Langenberger and Sara Bumrungsri. 8 Interview, Michael B. Commons. The interviewee described how a smallholder farmer allowed natural regrowth in one of her rubber plots near a forest preserve, selecting for useful species such as wild Garcinia (related to mangosteen fruit), and it now “looks like a forest” with thick vegetation.

29 RUBBER AGROFORESTRY Introduction

benefits, as native plants help support bio- Management intensity: Typically uses clon- diversity9 and provide additional sources of al rubber (but not necessarily); limited man- income and culturally important products agement and inputs. such as medicinal herbs and flowers.10 Allow- ing natural regeneration also reduces input Complexity: The longer the plantation is costs and labor, as fertilizers, herbicides and left unmanaged and natural succession al- time taken to clear vegetation are no longer lowed to proceed, the more complex it is needed. However, this practice may also be likely to be (in structure, function and spe- culturally stigmatized, i.e. a fear of increased cies diversity) and the more it will resemble snakes, mosquitoes, or ghosts in an over- a secondary forest. grown plantation,11 or smallholders being seen as “lazy” for having an “untidy” farm.12 Planting design: Usually standard planting densities as used in monoculture, but can There is grey area between “traditional” and vary depending on how much planning was “modern” jungle rubber, as there is a continu- involved. ous scale of management intensity, complexi- ty, and planning/design between the systems. Example locations: The best examples are known from Southern Thailand, but modern Associated terms: (improved) jungle rubber; jungle rubber systems likely exist in every (simple/complex) rubber agroforests. country with abandoned rubber plantations.

9 Researchers noted that rubber agroforests, particularly jungle rubber, supports higher biodiversity including birds, bats, insects, and earthworms (Interviews, Sara Bumrungsri and Uraiwan Tongkaemkaew). 10 Local native flowers, normally found in forests, spontaneously grow in rubber plantations and can be sold at higher prices. The flowers attract native birds, enhancing agro-eco-tourism potential, which is also a source of livelihoods (interview, Uraiwan Tongkaemkaew). 11 Interviews, Uraiwan Tongkaemkaew; Linda Preil. 12 Interviews, Linda Preil, and anonymous. Natural regeneration rubber in Malaysia. Credit: CC BY-NC 4.0 MWMH

30 RUBBER AGROFORESTRY Introduction

2.5 PERMANENT INTERCROPPING

Rubber trees can be interplanted with har- 2004; Zeng Xianhai, 2012; Sahuri, Rosyid and between timber and rubber trees. vestable non-timber and timber species, in- Agustina, 2016). Permanent intercropping cluding food and non-food crops (e.g. timber, systems are also commonly combined with Aside from research on jungle rubber systems, ). A wide range of species have been temporary intercropping of annuals (e.g. cas- the existing literature around social, economic intercropped with rubber, including annuals sava, maize, pineapple) and can also be com- and environmental outcomes of rubber agro- (e.g. cassava, maize), perennials (e.g. cocoa, bined with livestock or aquaculture. forestry is dominated by studies of rubber in- coffee), fruit trees (e.g. mangosteen, orange), tercropping practices and systems as described timber trees (e.g. teak, mahogany), palms, Rubber-timber systems are a distinct subcate- here, and agroforestry researchers also typical- vegetables (e.g. gnetum), spices (e.g. ginger, gory of permanent intercropping systems, due ly define rubber agroforestry in these terms cardamom), and mushrooms or various com- to different requirements of timber crops (e.g. (Box 1). For a comprehensive review of the binations of these. Permanent rubber inter- higher upfront costs, establishment needs, history and agronomic challenges of rubber in- cropping systems differ from temporary in- harvesting needs, timber regulations). Lan- tercropping, including a classification scheme tercropping (where annuals are planted only genberger et al. (2017) states that studies of and a list of species that have been evaluated in the first few years of rubber establishment) rubber-timber systems are scarce and some- in rubber intercropping systems, please see as intercrops are grown throughout the plan- times unreliable. However, several research- Langenberger et al. (2017). This study notes tation cycle i.e. after rubber trees mature and ers noted the potential for rubber-timber sys- that despite considerable field trials by rub- their leaves create a shaded environment in tems, especially in industrial plantation set- ber research institutes around the world and the plantation (canopy closure). Permanent tings, due to high economic returns and low its commonly cited benefits, there seems to intercrops can be planted before, at the same maintenance requirements. Native timber be limited adoption, or limited evidence of time, or after planting of rubber trees, de- trees can also become a source for seeds and adoption of permanent rubber intercropping pending on the light requirements of the in- saplings. Species may include teak, mahoga- systems. We discuss reasons for this in a later tercrops. There have been field studies eval- ny, or native tropical hardwoods (e.g. Shorea section of this report. uating different planting densities and spatial spp). Difficulties may arise around matching arrangements for permanent intercropping the planting/ cycles of rubber with oth- Associated terms: intercropping, inter-plant- with rubber (Rodrigo, Silva and Munasinghe, er timber species, and of canopy competition ing, mixed cropping, intercalary cropping, al-

31 RUBBER AGROFORESTRY Introduction

ley cropping, relay cropping. one other intercrop (e.g. rubber + tea, rubber ties, but may affect intercrop yields. Alterna- + gnetum). Complex intercropping would in- tive rubber planting designs have been stud- Management intensity: Typically uses clon- volve multiple intercrops (e.g. rubber + fruit ied, the most commonly recommended being al rubber. Requires planning of which crops to trees + vegetables). Structural and temporal the double-row avenue planting design with plant and when/where. Weeding and fertilizer complexity will depend on choice of inter- wider interspacing between rubber rows. regimes vary widely by country/individuals/ crops (annual/perennial, shrub vs tree, tim- system. ings of establishment). Example locations: Diverse examples in many countries in Southeast Asia, Africa and Complexity: Ranges from simple to complex. Planting design: Possible under typical rub- South America. Simple intercropping would involve rubber + ber monoculture planting design and densi-

2.6 RUBBER AS A TOOL FOR FOREST RESTORATION

A few researchers discussed the poten- terocarpus spp or Shorea spp, both tropical questration, while also providing income to tial of rubber agroforestry as a tool for re- hardwoods). The rubber trees can be tapped cover the costs of forest restoration, or for /,13 by planting for latex up until their productivity drops, resource-poor communities (Omokhafe, Im- rubber alongside native tree species on de- e.g. after 25-30 years, and then harvested for oren and Samuel, 2019). An economic mode- graded or low-yielding soils.14 These native timber, leaving native tree species to contin- ling analysis demonstrated that a rubber-na- tree species can provide high value timber, ue growing. In this way, the plot undergoes tive timber plot for ecosystem restoration non-timber forest products (NTFPs), or be (assisted) natural succession and resembles is financially viable and even profitable for ecologically important (e.g. rare and threat- a native secondary forest, promoting biodi- ecosystem restoration concession license ened species, such as shade-tolerant Dip- versity, ecosystem services and carbon se- holders (Harrison et al., 2020). In addition,

13 is the process of replanting a previously forested area with trees, while afforestation is planting trees in an area that had not been previously forested tree cover. 14 Interviews, Gerhard Langenberger; Rhett Harrison; Kenneth Omokhafe.

32 RUBBER AGROFORESTRY Introduction

rubber trees are being explored as a way to that old rubber or cocoa plantations con- facilitate afforestation and to ameliorate de- taminated by white root rot can be restored It’s a theoretical sertification in the humid savannah, and re- by using native forest trees, and the old rub- store forest status of the derived savannahs ber stands can be a nursing stand for the new concept – but if of Nigeria (Omokhafe, Imoren and Samuel, forest. everyone plants a 2019; Omokhafe 2020). It can also be used to restore soil and remove cocoa-related dis- “It’s a theoretical concept – but if everyone single native tree eases in Cote d’Ivoire.15 In addition, although plants a single native tree on every hectare, this idea is closer to forest restoration than it could contribute to genetic maintenance of on every hectare, it rubber agroforestry, a researcher suggested native trees.”16 could contribute to genetic maintenance of native trees.” 2.7 DEFINITION OF SMALLHOLDINGS Gerhard Langenberger AND PLANTATIONS

This report uses the terms “smallholder” and Strict definitions of smallholdings often use a smallholdings” to refer to rubber growers who 2-hectare threshold (for example as used by own or manage smaller plots of land with the FAO (Rapsomanikis, 2015) ), but the rel- some degree of autonomy, in contrast to plan- evance of size thresholds varies among coun- tation models of rubber growing where larger tries and other contextual factors. Individual areas of land are owned or managed central- cited studies should be checked if further in- ly by a company with the use of hired labor. formation about land holding size is needed.

15 Interview, Eric Penot. 16 Interview, Gerhard Langenberger.

33 RUBBER AGROFORESTRY Agroforestry: Effects

3 Agroforestry: effects on livelihood, social, environmental and climate resilience outcomes

This section of the report is based on livelihood, social and economic out- a detailed literature review and inter- comes. Almost all literature relates to view responses from experts on the ef- smallholder farmers, but descriptions fects of rubber agroforestry, compared of systems are given in all cases to re- to monoculture where possible, on late them large-scale plantations.

Food markets with local products in Thailand. Credit: CC BY-NC 4.0 EWT

34 RUBBERRUBBER AGROFORESTRYAGROFORESTRY Livelihood outcomes

3.1 LIVELIHOOD OUTCOMES

This section summarizes the effects of agro- forestry production systems in Lao People’s lands previously used by smallholder farmers forestry practices on smallholder farmer live- Democratic Republic (PDR) is shown in Box 2 are not covered here, because it is not related lihoods, including plantation-based agrofor- to demonstrate how land tenure affects food directly to agroforestry. estry systems, broadly grouped under specific security and farmer autonomy. Outcomes of themes. A comparative study of four agro- large-scale rubber plantation expansion onto

BOX 2 CASE STUDY OF SMALLHOLDER LIVELIHOODS IN LAOS: LAND TENURE, FOOD SECURITY AND AGROFORESTRY CONSTRAINTS

A study on effects of tree plantation establish- In Laos, intercropping is strongly dissuaded by immature rubber phase. Despite this, agricultur- ment for smallholder farmer livelihoods conduct- rubber companies (who hold contracts with al experts throughout Laos widely promote in- ed four experiments in Lao PDR, for both rubber smallholders to plant and grow rubber) except tercropping. Rubber companies also prevented and eucalyptus: plantations established under in the case of rice in year 1, and in some cas- integration of livestock into rubber plantations, concessions, contract farming arrangements, es maize on an ongoing basis. In some villages requiring farmers to pay compensation for any smallholder led agroforestry systems and planta- farmers stated that they were allowed to inter- rubber trees damaged by livestock; this led to tions, and village land lease schemes (Haberecht, crop with chilli, galangal, sesame or beans, but conflict between rubber and buffalo due to a 2010). This study concluded that constraints im- the farmers either did not have enough time, lack of grazing land, and which were central to posed on farmers by rubber companies, which or the soil was considered unsuitable for these village life. At a district level, there was a strong prevented them from diversifying their rubber specific crops. Companies stated that inter- effort to move from subsistence farming to systems, had negative impacts for farmers. crops would compete with rubber and reduce market-oriented farming, but this was challeng- yields, but meanwhile few incentives were of- ing in the transition phase while farmers waited fered for farmers to obtain income during the for rubber to become productive.

35 RUBBER AGROFORESTRY Livelihood outcomes

The concession model has been dominant in would be possible for a rubber system). ing agroforestry (incense-bark trees, banana Lao PDR so far, and much plantation expansion and rice) were at least double the returns from under this model has resulted in negative out- Independent establishment of agroforestry other systems, even plantations with inter- comes for customary land rights, livelihoods, by smallholders was not reported to be wide- cropped rice. Many farmers expressed a desire and environmental values. However, some plan- spread for rubber, but systems of incense-bark for autonomy, e.g. preferring to plant at ‘their tation companies have allowed local households trees (Persea kurzii) on seven-year rotations own’ tree spacing and selling ‘their own’ to intercrop within plantation boundaries, while with intercropped banana and rice, had been to companies independently of other farmers also providing wage labor opportunities. These established by smallholders independently. i.e. not being tied into contracts. It was not- companies were also reportedly “more par- ed that the lucrative banana intercrops under ticipatory, transparent, and locally responsive” In most cases, in the contract and independent the incense-bark trees would not be as possible during the land acquisition process. smallholder models, households did not have under eucalyptus due their high light require- formal land titles, but decisions were made in- ments; the same problem may apply to rubber. Land sharing models, where villages mapped stead based on locally-recognized customary land to be included in the plantation in a par- land rights following forest clearance for shift- All systems involving companies resulted in ticipatory process in exchange for village devel- ing agriculture. households receiving less income than the opment funds for infrastructure, could either companies predicted, due to theft of payments, result in labor being brought in by the company Net present values (the total predicted eco- lower yields/failure to plant intercrops, and in- to directly manage the plantation, or by con- nomic returns for a plot of land over a future ability to sell plantation trees at the end of the tracting local people to clear land themselves period of time, discounted to account for infla- cycle as expected. Overall, the study empha- and assume responsibility for planting and tion) or eucalyptus plantations under the four sized the importance of intercrops in tree plan- maintaining plantation trees. systems were compared (based on interviews tations for household benefits, that Lao farm- and questionnaires in four villages), including ers and rural communities prefer diversified Contract models involve companies providing input costs (zero for villagers in most cases as livelihood strategies to being reliant on single capital investment to establish rubber, market the company covered costs), benefits packages crops, and recognizes farmers’ desire to main- access and technical expertise, while farmers made to the villages, and crops including inter- tain a level of livelihood autonomy and agency, provide land and/or labor; benefits may be crops. Some contract farmers were unable to reinforcing earlier studies that show the im- shared via latex-sharing or land-sharing. In two sell their trees at the end of the plantation cy- portance of agroforestry systems in Lao PDR villages with land-sharing models, households cle, meaning some received no return for their (Simo, Kanowski and Barney, 2020). could farm crops (primarily rice) between rows investment at the end of the plantation cycle. of planted eucalypt trees (presumably the same Returns for independent smallholders practic-

36 RUBBER AGROFORESTRY Livelihood outcomes

3.1.1 INCOME DIVERSIFICATION, ECONOMIC ANALYSIS AND LIVELIHOOD RESILIENCE

To what extent can income and livelihoods hold income especially for the poorest households, but long-term economic sus- diversification through the adoption of agroforestry tainability of this industry is not guaran- systems help maintain income and livelihoods during teed (Jaramillo-Giraldo et al., 2017; Wallace, Gomes and Cooper, 2018). Harvesting wild the rubber immature period, and during periods of rubber in the Brazilian Amazon provides ex- rubber price volatility? tremely low yields on a per-area basis. Spe- cifically, with an average tree density of 1.67 trees/ha, and each tree producing 1-3 litres/ 3.1.1.1 WILD RUBBER external organizations (international CSOs, tree/year (compared to a global average of private companies, development agencies) to 2.26 litres/tree/year), 890 tons/year of dry Most examples of wild rubber production promote non-timber (NTFP) rubber could potentially be extracted from effects on livelihood to date come from Lat- extraction such as brazil nuts and other the large expanse of forests of Southern in America and specifically Brazil. In Brazil, means of sustainable livelihoods (WWF-UK, Acre (average = 0.36 kg/ha/year, i.e. 0.00036 rubber tapper communities associated with 2014; Wallace, Gomes and Cooper, 2018; Fitts, tonne/ha/year). While rubber extraction in extractive reserves have been diversifying Cruz­-Burga and La Torre-Cuadros,­ 2020). An native forests therefore is not economical- livelihood sources, including cattle ranching agroforestry researcher based in Peru noted ly viable without government subsidies, the which has been associated with forest clearing that “there was a little revival of wild rubber maintenance of the rubber tapper identity (Brown and Rosendo, 2000; Wallace, Gomes with a rubber producer association [in Madre is an important cultural value (Jaramillo-Gi- and Cooper, 2018) as well as moving away from de Dios], but this did not last due to many raldo et al., 2017). Partnerships with CSOs in forests to urban centers (Gomes, Vadjunec circumstances (market players, organization Rondonia, Brazil have improved the political and Perz, 2012; Wallace, Gomes and Cooper, structure, capacities etc).” empowerment of rubber tappers, but many 2018). In both Brazil and Peru, there have been households remain poor suggesting that in- community-based management (CBM) initia- Studies in Acre, Brazil found that wild rub- come security from wild rubber is question- tives, from both state governments as well as ber extraction can contribute to house- able (Brown and Rosendo (2000).

37 RUBBER AGROFORESTRY Livelihood outcomes

PERMANENT AND 3.1.1.2 years. This demonstrates the improved finan- TEMPORARY INTERCROPPING cial returns from simple high rubber yielding Intercropping strategies increase financial agroforestry systems relative to monoculture viability of rubber replanting for small- rubber in the Indonesian context (USAID holders in Indonesia, as shown by two re- Green Invest Asia, 2020). Another study of ports. A USAID report assessed the structure rubber smallholders in Jambi and South Su- of loans for smallholder replanting in Jambi, matra, Indonesia, investigated the feasibili- South Sumatra, and West Kalimantan in In- ty of selling the wood of old rubber trees to donesia, including monoculture and agrofor- finance replanting of rubber trees (WWF, estry (rubber + two or more intercrops) mod- 2020). The study found that rubberwood els (USAID Green Invest Asia, 2020). They sales alone were insufficient to provide a con- compared an adjusted Internal Rate of Return vincing investment case for replanting, and (IRR, a metric used to estimate the profitabil- needed to incorporate agroforestry to be ity of potential investments) between the two a viable financing scheme.The agroforestry systems, assuming either a single clearance (intercrops during immature rubber phase) and replanting event, or a two-phase stag- model, coupled with staggered clearance and gered clearance and replanting event (where replanting, decreased the cash shortfall of half the land is replanted in one year, and the smallholder farmers and directly reduced other half is replanted in the following year). their financing (loan) requirements. Intercrops considered included banana and pepper during the immature phase, turmeric In Thailand, several studies have shown the during the mature phase, and timber planted benefits of temporary and permanent in- alongside rubber at establishment. Only the tercropping in rubber production for small- agroforestry models produced an IRR greater holder incomes. In Northeast Thailand, rub- than 30% per annum, and only the agrofor- ber-cassava intercropping systems lowered estry model with staggered replanting was management costs by nearly 60% during a viable option for a commercial rate loan, six years of rubber mature immature phase, with a total repayment of $7,855 over seven compared to a monoculture rubber planta-

Children play under sheets of rubber on their parents’ plantation. Credit: CC BY-NC-ND 2.0 IFPRI

38 RUBBER AGROFORESTRY Livelihood outcomes

tion (Hougni et al., 2018). The cash income low) compared to monoculture farmers, who “Agroforestry systems from intercropping varied from 0 to 26.8% had an over-reliance on rubber trees for their of the household’s total annual income, income. The price volatility of other agricul- provide farmers with which can be of considerable importance for tural products also has an obvious impact on different sources of income low-income farmers (Hougni et al., 2018). In net outcomes. Farmers who planted fruits Northeast Thailand, where rainfall is a major primarily did so for self-consumption, while over different timescales.” constraint on crops during the dry season, the social role of edible species was also em- cassava is favoured as a second (‘insurance’) phasized. Livestock was thought to reduce crop in other systems as the tuber requires fertilization costs for rubber trees, while grow seedlings that can then be sold.18 The minimal care, little investment, and provides farmers also expected higher economic re- flowers attract native birds and enhance agro- greater flexibility in planting and harvesting turns from agroforestry systems (Stroesser eco-tourism potential.19 Anecdotally, based than longer term crops (Polthanee, 2018). An- et al., 2018). Moreover, agroforestry systems on interviews with farmers in Southern Thai- other economic modeling study in Thailand provide farmers with different sources of land, stingless beekeeping in rubber plots compared rubber monoculture with various income over different timescales. For ex- can even make the same amount of profit as agroforestry systems (fruit, timber, vegetable, ample, timber trees can be harvested and sold income from rubber itself.20 Moreover, agro- livestock) to characterize multiple sources of in 30-50 years, fruit trees like long kong, duri- forestry practices can reduce fertilization and livelihoods and incomes of smallholder farm- an and mangosteen provide seasonal income weeding costs due to healthier soils, the use ers (Stroesser et al., 2018). Most agroforest- annually, while vegetables provide weekly in- of organic animal manure, or the presence of ry farms were more robust to rubber price come (Stroesser et al., 2018).17 Timber trees cover crops,21 and indeed fertilizer use in agro- volatility (defined as systems where second- and native forest species also provide seed forestry systems is lower than in monocul- ary agroforestry products mitigated the effect and flowers with direct and indirect eco- tures in Southern Thailand.22 However, there of lower rubber prices, leading to a system nomic value. For example, farmers in South- is also evidence from Southern Thailand that that remains profitable even when prices are ern Thailand collect seeds of timber trees and there is not necessarily a difference in in-

17 Interview, Uraiwan Tongkaemkaew. 18 Interview, Uraiwan Tongkaemkaew. 19 Interview, Uraiwan Tongkaemkaew. 20 Interview, Michael B. Commons. 21 Interviews, Rhett Harrison, Sara Bumrungsri. 22 Interviews, Sara Bumrungsri and Uraiwan Tongkaemkaew.

39 RUBBER AGROFORESTRY Livelihood outcomes

come, costs, or yield between monoculture grow other crops for income, medicinal use, and agroforestry systems, but the study is un- or for food. The study also pointed out that clear about what types of income are included rubber estates should allow estate workers in these values (all crops, solely rubber, sec- to intercrop on immature rubber land along- ondary crops sold vs consumed) (Kittitorn- side maintaining the immature rubber trees kool et al., 2019). (Rodrigo, Thenakoon and Stirling, 2001). A financial assessment of rubber-banana inter- Further evidence from Asia and Africa, cover- cropping, based on agronomic experiments ing a broad range of intercrop species, show by the Rubber Research Institute of Sri Lanka, that intercrops can contribute a significant concluded that intercropping rubber with proportion of total farm or household in- banana at high densities can generate sub- come, which is especially important for the stantial income during the immature rub- poorest households, and sometimes even ber phase, and that the profitability was driv- more profitable than monocultures. en by banana yield, cost of inorganic fertiliz- ers, labor costs, and banana prices (Rodrigo, Smallholders in Sri Lanka have diverse strat- Stirling, Naranpanawa, et al., 2001). A study egies for intercropping, incorporating a wide from Moneragala district in Sri Lanka found variety of cash crops, food crops, or timber that 88% of farmers depended on rub- trees based on knowledge of soil and micro- ber-based agroforestry income during the climate conditions on the plot as well as their 6-7 years of rubber immature phase, with needs, and this knowledge comes from the lo- an average net return of ~LKR 247,157 per year cal farming community, personal experience, (US$ 1,621), with rubber-cocoa generating the and extension services (Rodrigo, Thenakoon highest annual returns (Sankalpa, Wijesuriya and Stirling, 2001). While rubber provided the and Ishani, 2020). In this case, it was conclud- main source of income, intercropping dur- ed that intercropping rubber with high-val- ing immature rubber phase allow smallhold- ue crops and livestock (such as groundnut, ers to intensify their small landholdings to cocoa, pepper, and raising dairy cattle) could

Chilli paste rural enterprise in rubber-dominated landscapes, Thailand. Credit: CC BY-NC 4.0 EWT

40 RUBBER AGROFORESTRY Livelihood outcomes

reduce poverty, but intercropping with ba- In Xishuangbanna, China, data from ~600 “The net present value nana and maize could not. Education, other rubber farmers showed that only 28% of agricultural income, and non-farm income rubber farmers have adopted intercropping, after 30 years of rubber-tea were significantly correlated with lower pov- accounting for 14% of land area managed by intercropping was greater erty, while larger household sizes was linked the surveyed farmers. Tea was the most fre- to higher poverty (Sankalpa, Wijesuriya and quently adopted intercrop (47% of farmers) than a monoculture of either Ishani, 2020). In an older case study of a Sri followed by coffee (14%) and maize (25%). crop after 30 years.” Lankan village, changes in forest policy in the Intercropping was an important source of 1990s led to a new reliance on agroforestry income for households in the lower income strategies (Caron, 1995). When the adjacent category. Intercrops contributed 16.5% on av- forest was established as a protected area, erage to total household income but could go An experimental study in Cote d’Ivoire com- restrictions on forest use meant that the vil- as high as 89% for low income farmers and, pared standard rubber monocultures with lagers could no longer rely on swidden agri- hence, a critical source of income for the rubber intercropped with coffee, cacao, lem- culture in forest and foraging of non-forest poorest farmers (Min et al., 2017). Similarly, on or cola tree (all of which were already timber products (NFTP) for their livelihoods. in Hainan, China, the net present value af- cultivated in the study area), in a field tri- In the face of land scarcity to grow their own ter 30 years of rubber-tea intercropping was al recording yields and inputs for each crop food, homegardens incorporating cash crops greater than a monoculture of either crop af- over 17 years. In the intercrop systems, rub- (rubber and tea were the largest sources) ter 30 years based on measurements taken at ber trees were planted in a double row with and subsistence crops became a common a state farm (Guo et al., 2006). State rubber wide inter-rows (16m) to allow shorter tree livelihood strategy for villagers. Rubber and farm workers in Xishuangbanna also prac- crops to thrive. The yield of individual rub- tea could provide cash income to buy food, ticed temporary intercropping during imma- ber trees was unaffected by intercropping. and families interplanted flowering and fruit ture rubber phase (with pineapple, rice, and Rubber-coffee and rubber-cacao were sig- trees, tubers, and vines in between rubber vegetables) as a livelihood diversification nificantly more profitable than other inter- rows for food. Rubber tapping was particular- strategy (Xu, 2006). crops and monoculture up to year 12, with ly done by women, alongside other activities positive gross margins from year 3 for coffee, in homegardens (Caron, 1995). In two regions of Mindanao, Philippines, in- and year 4 for cocoa. Rubber monocultures tercropping between rubber trees yielded 18 only reached breakeven profitability in year - 32% of total farm income (Furoc-Paelmo et 8. However, beyond year 13, the difference al., 2018). in profitability between monocultures and

41 RUBBER AGROFORESTRY Livelihood outcomes

coffee/cocoa intercrops was no longer sig- cropping. Intercrops included cassava, yam, “Households practicing tree nificant. The low price of lemons made rub- maize, plantain, watermelon, cocoyam, rice, ber-lemon unprofitable. Rubber-cola was also pepper and millet in various combinations, cropping had diversified unprofitable because cola nut trees only be- and all intercrop systems had positive incomes, and those using come productive at year 7. Rubber remained gross margins (i.e. made profit after account- the most important cash crop, accounting for ing for costs). Cassava had the highest return agroforestry had better food 88% of total revenues, with intercrops con- per hectare in Edo, Delta and Ogun states, security and nutrition.” tributing 4% (cola) to 25% (coffee) (Snoeck but coco yam and maize had the highest re- et al., 2013). turn per hectare in Akwa, Ibom and Kaduna states. Results depend on local market prices A survey of 80 households in Liberia, assess- (T. U. Esekhade et al., 2014). Another study Experimental work done since 1987 in ing the socio-cultural feasibility of increas- in Nigeria found that all 20 rubber farmers northern Gabon by the CATH (Centre ing agroforestry practices and tree cropping surveyed practiced temporary intercropping d’Appui Technique a l’Heveaculture, Tech- more widely (including rubber intercropped during years 1-3 of rubber establishment, in- nical Support Centre for Rubber Growing) with rice, cassava and a bitterball vegeta- creasing farm incomes. Intercrops included has resulted in a range of crop management ble), found that increased income was the melon, maize, cassava, yam, pineapple, plan- sequences for improving the productivity main motivator (Fouladbash and Currie, tain, banana, melon, groundnut, cowpea and of traditional holdings. Intercropping with 2015). The survey also found that households soybean. Cash income from rubber provided food crops has a positive effect on rubber practicing tree cropping had diversified in- $670-720 per year (mean per village, n = 10 tree growth. This work found that rice/ comes, and those using agroforestry had bet- per village), and secondary crops provided ground-nut rotation gave satisfactory re- ter food security and nutrition (Fouladbash $500-550; total income was $1,234-$1,340, but sults, but that plantain generated the high- and Currie, 2015) (see also section 3.1.5). after input costs, net income was $324-$420 est income (Enjalric et al., 1999). per year. These earnings were considered rel- A study by the Rubber Research Institute of atively low compared to other rubber-arable Nigeria surveyed 33 smallholder farmers crop systems in Nigeria (Esekhade, Ogeh and across five states who practiced rubber inter- Akpaja, 2006).

42 RUBBER AGROFORESTRY Livelihood outcomes

3.1.1.3 MARKETS FOR economic crises (Lehébel-Péron, Feintrenie SECONDARY AGROFORESTRY and Levang, 2011). Modeling of rubber-teng- PRODUCTS kawang (a Shorea sp. tree that produces fat- Conceptually, rubber agroforestry systems ty fruits, that can be processed for use as a provide a higher yield from the same amount substitute) agroforestry in West of land area compared to monocultures, as Kalimantan suggests that this could be more any of the products from intercropping would profitable than tengkawang monoculture. provide additional value on top of the rubber This analysis was based on field measures and harvest. However, income benefits from sec- interviews with farmers about input costs and ondary crops in rubber agroforests are only local market prices. This tree species was tra- possible if markets and market access exist.23 ditionally cultivated, but low fruit prices and This is the key limitation for agroforestry: increasing demand for timber (Shorea are for example, in rubber-lemon intercropping hardwood trees) mean many trees have been in Cote d’Ivoire (Snoeck et al., 2013) or rub- felled, rather than retained for fruit harvest ber-rattan agroforests in Kalimantan due to (Winarni et al., 2017). Promisingly, recent domestic policies that depress raw rattan surveys of a rubber agroforestry experiment prices (van Noordwijk et al., 2014). Economic have shown that robust markets are emerg- modeling work in Indonesia has shown that ing for some agroforestry crops, particularly in Sumatran jungle rubber agroforest prod- fruits (Penot and Ari, 2019). Hence, the de- ucts were quite well valued, but despite this, velopment of regional markets for raw and returns to land remained low; the authors value-added secondary agroforestry products identified Parkia speciosa as a tree species (e.g. via strengthening farmer networks, co- that could potentially improve jungle rub- ops and associations) should be a key consid- ber productivity, and help farmers cope with eration for initiatives promoting agroforestry.

Food markets for intercrops from rubber 23 Interviews, Eric Penot and Bénédicte Chambon. intercropping systems in Thailand. Credit: © both images EWT

43 RUBBER AGROFORESTRY Livelihood outcomes

Experimental plots of high-yielding (clonal) 3.1.1.4 PAYMENTS FOR ing and subsequent surveys in Xishuangban- rubber agroforestry systems were set up by ECOSYSTEM SERVICES AND na showed that only effectively planned PES ICRAF in Kalimantan in 1994. A review of evi- ECO-CERTIFICATION FOR schemes can successfully aid transfer of rub- dence and outcomes from these experiments AGROFORESTRY ber monocultures into agroforestry systems in 2019 showed that: income diversification (Smajgl et al., 2015). from fruits and timber led to better economic Environment-economic trade-offs are com- resilience. However, poor markets for fruits mon in agricultural systems and payments for and timber are currently real constraints for ecosystem services (PES) schemes are one “Eco-certification is a multi- further development of these systems. Peo- mechanism to offset the economic cost of stakeholder approach that ple in the landscape where the experiments e.g. wildlife-friendly agroforestry by provid- took place were experiencing land scarcity, ing a price premium or other financial incen- can incentivize agroforestry due to conversion of much land to oil palm tive. In Indonesia, PES have been suggested production practices with a by companies. Control of the damaging and to support very low-yielding but biodiverse fire-prone Imperata grass was successful us- jungle rubber systems. In Xishuangbanna, price premium for both industry ing cover crops in rubber systems, with bene- China, a contingent valuation survey of 2,500 and small-holder producer.” fits for farmers due to reduced fire risk. Over- people living in the city of Jinghong revealed all, initial interest in rubber agroforestry and a willingness to contribute financially to a re- improved rubber growing practices in 1994, duction of existing rubber plantations for the Eco-certification is a multi-stakeholder that led to this experiment, has fallen away sake of a partial restoration of the local rain approach that can incentivize agroforestry in favour of oil palm cultivation - however, forest. Interestingly, 58% of respondents did production practices with a price premium many farmers had kept rubber on to diversify not think it was actually acceptable to put an for both industry and small-holder producer. their farming, and valued agroforestry. How- economic price on nature, but 65% disagreed Such certification systems have successfully ever, knowledge of good tapping practices to that they have a right to a sound environment been introduced for coffee and cocoa produc- maintain yields, and availability of high-qual- without having to pay for it (Ahlheim, Börg- tion (Tscharntke et al., 2015a) and have been ity clonal planting material, are still in short er and Frör, 2015). However, PES approaches suggested for other natural resource use is- supply (thanks to abandonment of initiatives must be carefully planned and monitored to sues (Wanger et al., 2017). The clear benefit of since 1994 in favour of oil palm development) lead to the intended and not counterintuitive eco-certification is that it is a customer and (Penot and Ari, 2019). outcomes. For example, agent based model- demand-driven, rather than government-de-

44 RUBBER AGROFORESTRY Livelihood outcomes

pendent. However, in comparison to coffee exist for rubber plantations (e.g. FSC; Fair more market-based incentives for uptake of and cocoa, where the awareness of certified Rubber e.V; ; Global Or- agroforestry practices and increase awareness products is around 50% in Europe and North ganic Latex Standard) but uptake is currently of the multiple values (both market-based America (Tscharntke et al., 2015b), certified very limited. Moreover, the lack of definition and non-market based values) of agroforestry product market share of rubber is limited, for agroforestry systems make certification among both consumers and producers/man- partly due to the non-consumer facing at- of rubber agroforestry a challenge. Neverthe- ufacturers. tributes of most rubber end products (e.g. less, options for agroforestry eco-certifica- ). Several eco-certification schemes do tion should continue to be explored to create

3.1.2 LAND AND LABOR AVAILABILITY AFFECT AGROFORESTRY PROFITABILITY

Do rubber agroforestry systems provide improved be noted that some agroforestry practises may actually reduce labor requirements returns on land and labor? over time, such as reducing intensity of weed removal or the use of long-term cover crops In general, constraints on land and labor For larger holdings, or industrial plantations, to suppress weeds, while providing addition- availability strongly affect the profitabili- maximising yields from a single crop may be a al benefits for soil and water management. ty of agroforestry practices and systems for preferred strategy, particularly for large-scale Strategies such as the selection of species farmers. Agroforestry or intercropping could business operations. In addition, where land that require little extra labor until the op- be a viable diversification strategy for farm- constraints are less of a concern, income or tion to harvest becomes preferable over a fo- ers with small plots of land, where land is a portfolio diversification can be done at the cus on rubber (e.g. due to market price chang- key constraint but additional labor is availa- farm level (e.g. monocultures of different es, such as in Southern Thailand), and which ble, although off-farm livelihood diversifica- crops), which is simpler to manage than inter- provide benefits for soil and water man- tion options may also tie up labor availability. cropping systems.24 In these cases, it should agement in the interim (such as in experi-

24 Interview, Gerhard Langenberger.

45 RUBBER AGROFORESTRY Livelihood outcomes

mental systems in China), could be attractive. meaning harvesting is not being undertaken versification strategy aside from agroforest- (Tata, 2019). ry. This case study particularly demonstrates Labor availability is repeatedly reported to the importance of land and labor constraints be limited in case studies from Asia, where Jungle rubber has lower labor requirements for choice of farming practice. It should be most rubber is produced, but is not reported than monoculture (104-115 person days per to be a problem in case studies from Africa. ha per year vs. 211 in monoculture) (Leimo- “Constraints on labor Constraints on labor availability mean that na and Joshi, 2010). Detailed work on mature the integration of additional plants into rub- productive jungle rubber and monocultures availability mean that the ber monocultures either needs to be highly in Jambi, Sumatra, Indonesia, has shown integration of additional plants profitable, or must require little additional that the gross margin per unit of land (ha) is labor (for example, jungle rubber), for adop- much more variable, but significantly higher, into rubber monocultures tion of agroforestry to become widespread in monocultures (up to ~$800 USD per ha in either needs to be highly (Langenberger et al., 2017). For example, in 2015) than in jungle rubber, due to latex yields the Philippines, some areas of rubber planta- that are 2-4 times higher (Clough et al., 2016). profitable, or must require tions in Makilala, North Cotabato, are man- As land is a constrained resource, and jungle little additional labor.” aged as agroforestry systems, but they do not rubber is not competitive with monoculture contain any high value (presumably meaning per units of land, many farmers opt for the cash crop) intercrop species, due to the cost monoculture system, or even for monoculture noted that this study does not take into ac- of hiring additional labor to maintain addi- oil palm rather than rubber. In contrast, gross count longer term costs and benefits (which tional crops, and the perceived risk of rubber margin per unit of labor was not significantly could be estimated using net present value, trees contracting diseases from high-value different between the two systems, but was discounting costs and returns over time into intercrop species (see section 3.1.4 on pest greater in oil palm monocultures, meaning the future), but compares returns for a pro- and diseases). Instead, additional plant spe- where labor is a scarce resource, oil palm ductive year of each system. Establishment cies are allowed to naturally regenerate (low could be favoured over either jungle rub- costs over shorter 25-year planting cycles in labor), and are intended for plantation work- ber or rubber monoculture (Drescher et al., monocultures are likely greater than in jungle ers’ consumption (Agduma et al., 2011). Sim- 2016). The reduced labor inputs for oil palm rubber systems where replacement of rubber ilarly, rattan harvesting from rubber-rattan allow people to undertake additional off-farm trees is done continuously. However, contin- agroforests in Kalimantan is labor intensive, livelihood activities, representing another di- ued conversion of jungle rubber agroforests

46 RUBBER AGROFORESTRY Livelihood outcomes

to monocultures in this region indicates that greater returns to labor relative to monocul- Finally, wild rubber tapping in the Amazon farmers perceive that monocultures are more ture, but some agroforestry systems provid- is difficult because wild rubber trees grow profitable. ed poorer returns per land area relative to far apart in the forest and it takes substantial monoculture. The best agroforestry systems, time to collect sufficient latex to be profit- Another study compared the livelihoods and both in terms of land and labor, included able, and economic returns are meagre (due incomes of smallholder farmers in Thailand rubber trees with intercropped fruit and to low rubber prices and competition with from rubber monoculture versus various timber trees. Farmers also undertook off- plantation rubber) (Brown and Rosendo, rubber agroforestry systems (fruit, timber, farm activities to complement their family 2000; Gomes, Vadjunec and Perz, 2012; Jara- vegetable, livestock) (Stroesser et al., 2018). income (Stroesser et al., 2018). millo-Giraldo et al., 2017). All agroforestry systems had the same or

3.1.3 YIELDS AND PRODUCTIVITY Do rubber agroforestry systems affect the yield and yields of 0.994 tonnes/ha in 2017. However, this average figure masks strong differenc- productivity of rubber trees and intercrops? es in yields between production from jungle rubber (around 0.5 tonnes/ha) compared to Evidence for differences in rubber yields be- 3.1.3.1 RUBBER YIELDS monocultures growing clonal planting mate- tween agroforest and monoculture systems, Rubber yields vary greatly among the big- rial (1.4 – 1.8 tonnes/ha). By contrast, Thailand and for yields of intercrops, is summarized gest producing countries in Asia, with aver- produces 1.8 tonnes/ha, and Vietnam and Ma- here. The effects of agroforestry practices on age yields in Indonesia being particularly low laysia’s productivity stands at 1.72 tonnes/ha soil health, water availability and microclimate compared to neighbouring countries. Aver- and 1.51 tonnes/ha respectively, due to a much on rubber tree stress, growth and yields are age yields are only 1.04 tonnes/ha (per year, greater proportion of rubber area being plant- also mentioned (see sections 3.3.1 and 3.3.3). presumed), with smallholders, who manage ed with high-yielding clones. It is claimed that 83% of the planted area in Indonesia, having around 60% percent of smallholder rubber

47 RUBBER AGROFORESTRY Livelihood outcomes

cultivation in Indonesia is in rubber agrofor- 2019). In particular, ethylene (a plant hor- ests, or jungle rubber (USAID Green Invest mone commonly used to stimulate plant Asia, 2020) (although no source was given growth and fruit ripening) stimulation is for this estimate). Improving rubber yields often mentioned in discussions around rub- is considered key for improving farmer live- ber yields, as it allows a reduction in tapping lihoods, as rubber provides the bulk of cash frequency, and therefore increases returns income even in agroforestry systems. The ev- to labor thanks to an increase in yield per idence summarized here indicates that per- tapping day by up to 78%. Fertilizing during manent and temporary intercropping of the immature period may accelerate tapping rubber trees has either no effect, or a pos- commencement, and increase latex yield in itive effect, on rubber yields. Studies from the first few years of production, but current Sri Lanka, India, and Nigeria found that in- recommendations likely lead to over-fertili- tercropping improved rubber growth, but zation (Vrignon-Brenas et al., 2019). Agrofor- rubber-maize and rubber-bamboo intercrops estry strategies (cover crops, intercropping in Thailand decreased rubber growth. and leaving crop residues on the soil) are widely practiced and can help fulfil nutrient Improvements in latex yield have been needs of rubber trees (Vrignon-Brenas et al., primarily driven by the development of 2019), e.g. studies from Kerala, India show high-yielding clones and improvement of that the use of farmyard manure can reduce tapping strategies (which improves long- the amount of inorganic fertilizer used by up term, rather than annual, yields by prolong- to 50% without a reduction in growth rates ing the number of years for which trees can (Abraham, Joseph and Joseph, 2015). be tapped) while fertilizer application seems to be only secondary (Vrignon-Brenas et al., Rubber yield and productivity per tree are

Rubber harvest and drying rubber mats in Dawei, Myanmar Credit: © both images TCW

48 RUBBER AGROFORESTRY Livelihood outcomes

not considered to be affected by intercrop- imental plots of high-yielding (clonal) rubber beans (Phaseolus vulgaris) increased per-tree ping,25 if the rubber trees are not shaded by agroforestry systems set up by ICRAF/CIRAD rubber yields relative to rubber monocul- taller trees,26 and there are no other plants in Kalimantan in 1994 showed no impact of tures (double row planting, with a wider in- or trees in the rubber line,27 as commonly agroforestry practices on rubber production, ter-row than typically used in rubber planta- reported by farmers experienced in rubber as long as there were no trees above the rubber tions) (Righi et al., 2008). agroforestry. Multiple studies support this canopy (Penot and Ari, 2019). Experiments in assertion, showing that intercropping has Sri Lanka intercropping banana during the no effect on rubber yields (per tree; yields first four years of rubber establishment also “Intercropping had no effect per land area will be altered if planting densi- found that intercropping had no effect on la- on latex yield per tree, and ty of rubber trees is changed). A series of ex- tex yield per tree, and even enabled higher periments by the Rubber Research Institute yield per hectare than rubber monoculture even enabled higher yield of India between 2001 and 2014 showed that plots, as more trees could be tapped earli- per hectare than rubber rubber yield was not affected by a variety of er in the intercropped plots (Rodrigo et al., intercropping strategies under typical mono- 2005). Results of a field trial inCote d’Ivoire monoculture plots.” culture planting design and rubber tree den- showed that the yield of individual rubber sity (Jessy, Joseph and George, 2017). These trees was unaffected by intercropping (with intercrop experiments involved (i) inter- coffee, cocoa, lemon, cola) although spacing A 17-year experimental study in Hainan, planting young rubber with coffee, Garcinia, between trees was increased relative to the China, asked whether changing the planting and , (ii) interplanting mature monoculture control (Snoeck et al., 2013). arrangement of rubber trees (“double row”) rubber with shade-tolerant medicinal plants, Rubber yields as reported by farmers did not allowed more light to reach the understory, and (iii) temporary intercropping with annu- differbetween agroforestry and monoculture to increase the yields of intercrops, affected al vegetables during the wintering (leaf-shed- systems in Southern Thailand (Kittitorn- rubber yields relative to a normal planting ar- ding) season of mature rubber, demonstrating kool et al., 2019; Warren-Thomas et al., 2020). rangement (“single row”) (Huang et al., 2020). that diverse intercropping strategies could An experimental study in southeast Brazil The double row plots had two adjacent lines work (Jessy, Joseph and George, 2017). Exper- found that intercropping rubber trees with of rubber trees planted 4m by 2m apart in a

25 Interviews Rhett Harrison, Eric Penot, Sara Bumrungsri, Uraiwan Tongkaemkaew, Kenneth Omokhafe. 26 Interviews and email consultations, Rhett Harrison, Eric Penot, and Kenneth Omokhafe. 27 Interviews and email consultations, Eric Penot and Bénédicte Chambon.

49 RUBBER AGROFORESTRY Livelihood outcomes

‘row’, with an inter-row spacing of 20 m (420 productivity per tree. However, they report- significant higher rubber growth (Jessy, Jo- trees per hectare), while the single-row plots ed that smallholders tend to plant rubber at seph and George, 2017). A third experimental were typical of most rubber plantations with much higher densities, which can reduce rub- study in Indonesia found that intercropping trees planted in rows 7m apart, with trees 3m ber productivity per tree,28 as well as creating with annual crops positively affected rubber apart (480 trees per hectare). Rubber yield shadier environments which in turn reduce tree growth (Penot, 1997). A fourth, from per tree did not differ between the dou- the productivity of intercrops.29 Nigeria, conducted over four years, found ble-row or single-row system, but total yield rubber intercropped with cassava and plan- was lower in the double-row system only due Lastly, four studies, from Sri Lanka, India, tain had a higher growth rate than monocul- to a lower planting density of rubber trees Indonesia, and Nigeria, found that intercrop- ture rubber or rubber intercropped with tree per hectare. Another field experiment in Sri ping has a positive effect on rubber tree crops (Avinger and cherry), allowing earlier Lanka used five spatial arrangements of rub- growth. A comparison of rubber tree growth commencement of tapping time (T. Esekhade ber trees (single row, double row, triple row, and yields in monocultures and rubber-ba- et al., 2014). However, the use of nitrogen and three plant triangular and four plant square nana intercropping systems in Sri Lanka potassium fertilizers for sustained growth cluster) to test whether increased spacing found that intercropping improved rubber rates was recommended as continuous inter- between rubber trees would affect rubber growth over the six years of the study (Rod- cropping could lead to soil nutrient depletion tree growth and yields. Results over nine rigo et al., 2005). Trees in the intercrop treat- (T. Esekhade et al., 2014). In contrast, mod- years showed that rubber growth and yields ment matured four months earlier than eling of rubber-maize intercropping systems were highest in single row alleys and cluster monocultures, and while tree girth and height in northern Thailand suggests that rubber designs than other systems, but annual rub- were greater in the intercrop system, bark tree growth is reduced in intercropping vs ber yield per hectare did not significantly thickness was unaffected. Intercropping also monocultures, and that maize growth during differ across planting designs (Rodrigo, Silva had no effect on latex yield per tree, meaning the immature rubber phase needs to be sup- and Munasinghe, 2004). Interviewed experts rubber yields per hectare depended only on ported by fertilization (Pansak, 2015). A study also considered that double-row avenue sys- rubber tree planting density. A second study, comparing a mature rubber monoculture (20 tems at a standard planting density of 410- from India, found that intercropping with years old) with an adjacent agroforest (20 420 trees/ha should not result in decrease in coffee, vanilla, Garcinia, and nutmeg led to year old rubber + 10-year old bamboo in the

28 Interview, Rhett Harrison. 29 Interview, Gerhard Langenberger.

50 RUBBER AGROFORESTRY Livelihood outcomes

inter-row) in southern Thailand found that In Brazil, work in rubber-coffee agroforests rubber tree girth was reduced in the agro- established in 1999 (with rubber tree rows forest, but this could be attributed to either placed a-typically, with large 16m gaps be- the lack of fertilization in the agroforest, or tween double rows 4m apart) showed coffee the presence of bamboo but there was no evi- plants had lower when grown under dence for root competition between bamboo shade (although total biomass and therefore and rubber (Andriyana et al., 2020). carbon stock was greater in the rubber-cof- fee system), but coffee yields were similar between the two systems, with more relia- 3.1.3.2 INTERCROP YIELDS ble coffee yields in the combined system, In general, shading from the rubber canopy indicating that rubber-coffee agroforestry are expected to reduce yields of intercrops systems are viable in the Brazilian context, (see also (Langenberger et al., 2017) for a dis- where coffee is the main crop (Zaro et al., cussion), and this was confirmed by several 2020). In contrast, in another experiment studies reviewed below but results varied in Brazil, planting coffee in full sun versus based on the intercrop used. Shading from in the shade of rubber trees, showed that the rubber canopy may sometimes even be air temperatures were reduced and humid- beneficial, as shown for banana in Sri Lanka, ity increased, resulting in changes in coffee and it has also been suggested that shading growth, including a reduction in coffee crop may increase the productive lifespan of the yield due to shading by rubber (Araujo et intercrops (an avenue for future agroforestry al., 2016). Another study found that sugar- research).30 Increasing the planting density cane growth and yields decreased with of intercrops could be a way to recoup yield proximity to rubber trees, indicating that reductions from rubber shading. rubber-sugarcane intercrop systems may be

Salak intercrop harvest in Thailand 30 Interview, Gerhard Langenberger. Credit: © both images CC BY-NC 4.0 EWT

51 RUBBER AGROFORESTRY Livelihood outcomes

most productive for sugarcane yields dur- medicinal plants in India. In the third exper- mixed results for the effects of rubber tree on ing the immature rubber tree phase, or may iment, annual vegetables were intercropped intercrops. Cinnamon can be intercropped need to be managed for by reducing shading with mature rubber trees during the rubber with rubber, but it is most productive during of sugarcane by mature trees (spacing, or tree leaf-shedding season, again with no impact the immature phase, with yields declining ). Rubber yields were not investigated on rubber yield and decent yields for some by 70% after eight years (when rubber can- (Guedes Pinto et al., 2006). vegetables (e.g. Amaranthus and cucumber). opy closes). A study of rubber-cinnamon in- tercropping systems at the Rubber Research Three experiments conducted by the Rub- In Hainan, China, the yields of yam bean, Institute of Sri Lanka, where cinnamon was ber Research Institute of India between 2001 peanut, soybean, common bean and Arabica planted under 15-year old mature rubber and 2014 showed that some intercrops per- and Robusta coffee were compared between trees, found that cinnamon bark yields formed better than others (Jessy, Joseph two rubber planting arrangements (see pre- were unaffected by fertilizer application and George, 2017). In one experiment, cof- vious section). The double row system al- or cinnamon planting density. Therefore, fee, vanilla on Glyricidia standards, Garcinia lowed direct sunlight to reach the intercrops. although cinnamon is limited by light avail- and nutmeg were planted with young rubber All crops grown as intercrops yielded less ability, increasing planting densities under without modifying rubber plantation man- than when grown in their own monocul- mature rubber can increase yields (Pathiratna agement. The initial yield of all the intercrops tures, but yield reductions varied among and Perera, 2006). Pepper did not perform was good, but when the rubber canopy began crops: yam bean produced 75% of its yield in well under mature rubber, neither did tea to shade out the intercrops, only vanilla and monoculture, while peanut yielded only 38%. after six years of rubber growth (even with coffee sustained their yields. In the second Robusta coffee yields were 35% lower than in 30% reduction of rubber planting density) experiment, nine shade tolerant medicinal monoculture, but intercropped Arabica coffee (Rodrigo, 2001 as cited in (Rodrigo, Silva and plants were intercropped in mature rubber yields were similar to monoculture Robusta. Munasinghe, 2004)). However, another study plantations. All nine plants were established The authors concluded that based on yields found that banana and rubber growth was successfully and produced decent yield with- alone, rubber-yam bean and rubber-Arabica improved in rubber-banana intercropping out affecting rubber yield (Alpinia calcarata coffee schemes were the two most promising systems, suggesting that in this case shade and Strobilanthes cuspida were highlighted as intercrops (Huang et al., 2020). could be beneficial for in terms of moderating the most promising species) but the authors microclimate and alleviating plant stress (Ro- noted that market demand was limited for In Sri Lanka, several studies have found drigo, Stirling, Teklehaimanot, et al., 2001).

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3.1.4 PESTS, DISEASE AND INVASIVE SPECIES Do rubber agroforestry systems affect the occurrence of via interventions such as intercropping. In China, the presence of cassava intercrop be- pests and diseases? Can agroforestry practices improve tween rubber trees seems to increase growth pest and disease management in rubber? of a rubber-tree pathogen, white root disease Rigidoporus lignosus (although had no effect on another pathogen, Corynespora cassiicola). Agroforestry practices in non-rubber systems tems can, both be effective to regulate various The authors suggest that cassava intercrops have been shown to provide pest control pests and diseases but also amplify their oc- should not be recommended where the R. lig- services relative to monoculture production currence depending on circumstances. nosus pathogen is present (Liu et al., 2020). (Maas et al., 2016), although evidence for rubber agroforestry is currently lacking, and Interviewees reported that diseases can build The fire-prone but invasive Cogon grass (Im- there are indications that some diseases could up in the soils of monoculture rubber plan- perata spp.) poses major problems for land be more prevalent in rubber agroforests.31 tations. 32 For example in Malaysia, the soil management for agriculture in Southeast Asia Climate change also affects the distribution becomes unsuitable for rubber cultivation (Bagnall-Oakeley et al., 1996). Intercropping and intensity of pests and diseases of plan- after two planting cycles, but this may be during the immature rubber phase helped tation crops and subsequent intensification ameliorated with intercropping if rubber and manage Imperata re-growth in smallholder approaches, meaning agroforestry strategies intercrop rows can be shifted or rearranged rubber farms in Sumatra, Indonesia (Penot that reduce these risks will also theoretical- within the plot to avoid build-up of diseases and Ari, 2019). Moreover, jungle rubber sys- ly improve climate resilience (Tscharntke et in the soil. This is an avenue for future rub- tems effectively controlled Imperata invasion al., 2011a; Wanger et al., 2018a) (also see sec- ber agroforestry research, as there do not in the long term. However, Imperata regrowth tion 3.3.1). Results from rubber agroforestry appear to be any long term studies on the occurred once intercropping ceased (unless are mixed, suggesting that intercropping sys- build-up of soil pathogens or their control intensive weed management was undertak-

31 Email correspondence, Eric Penot. 32 Interview, Rhett Harrison.

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en) (Bagnall-Oakeley et al., 1996). On the oth- rubber agroforestry species could act as res- er hand, agroforestry practices can harbour ervoirs for leaf-eating pest mites (Bellini, de more species such as snakes33 or wild pigs Moraes and Feres, 2005) and found that mites (Vincent et al., 2011) that are considered dan- in both agroforestry and monoculture sys- gerous pests by rubber farmers. tems were similar (numbers of species, gen- era and families), and there was no evidence Pests of rubber crops are more prevalent in that agroforestry species served as a reservoir South America, where Hevea brasiliensis is for pest mites. native. In Brazil, leaf-eating pest mites can severely damage rubber trees in plantations Intercropping coffee with rubber may help (severe infestation of Calacarus heveae mites reduce pest and disease damage in coffee by can cause damages on leaflets, intense defo- increasing shade, compared to coffee mono- liation of plants and losses in latex yields of cultures with full sun. Studies from Brazil up to 54%). However, these mites can be in- found that coffee plants located ≤ 2m away fected with fungi (e.g. Hirsutella thompsonii), from rubber trees had the lowest incidence which can act as a natural pest control of the of coffee leaf miner (Androcioli et al., 2018), mites. A study comparing agroforestry with lowest incidence of disease (Cercospora leaf monoculture rubber found greater infection spot) (Androcioli et al., 2015), but damage rates with the fungus, implying that agrofor- from leaf miners varied with distance to estry cultivation practices help support natu- rubber trees and season (Righi et al., 2013). ral pest control of leaf-eating mites (Nuvolo- However, increased shade may result in low- ni et al., 2014). Another study asked whether er coffee yields.

33 Interview, Uraiwan Tongkaemkaew.

Rubber agroforest in Thailand. Credit: E Warren-Thomas

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3.1.5 FOOD SECURITY AND NUTRITION Does adoption of rubber agroforestry improve limited information from the literature and interviews directly relevant to rubber agro- household access to food and nutrition? forestry and food security issues. We have found only one study (from Liberia) looking The latest global assessment of food security ladbash and Currie, 2015), whereas in many at whether adoption of rubber agroforest- and nutrition conducted by the Food and Ag- parts of Southeast Asia, it is argued that food ry improves household food security, and ricultural Organization (FAO) estimate that security is linked to market-based livelihood none specifically looking at nutrition. The 8.9% of the world population are experienc- strategies rather than local sufficiency of food few studies (across several countries) we re- ing food insecurity (FAO/IFAD/UNICEF/FFP/ production (van Noordwijk et al., 2014). How- port here found that food crops and livestock WHO, 2020). This translates to 690 million ever, the FAO recommends that agricultural from rubber agroforestry were used to sup- undernourished people, including 64.7 mil- policies encouraging a move towards inte- plement household food consumption, but lion in Southeast Asia, where most rubber is grated methods of food production, includ- also indirectly as a source of cash income being produced (although the estimate did not ing agroforestry, are considered, in order to for purchasing food (sometimes to mitigate differentiate between urban and rural popula- improve dietary diversity, as well as provid- the loss of the community’s access to forest tions). Food security and nutrition issues are ing other benefits (FAO/IFAD/UNICEF/FFP/ resources for food and income). We also note strongly region and context dependent but WHO, 2020). evidence for the very substantial improve- overall, smallholder farmers continue to be ments in incomes from rubber cultivation the backbone of global food security (Tschar- While agroforestry alone cannot solve all the relative to subsistence farming of rice for ntke et al., 2012). A global meta-analysis of challenges of food insecurity and malnour- farmers in Sumatra, Indonesia (Penot, 2004). 45 studies found a small but significantly ishment, it can be part of a multi-pronged positive relationship between diversifying strategy to improve and diversify food pro- A survey of 80 households in Liberia found smallholder production and nutritional di- duction within the current monoculture cash that agroforestry households (not just rubber versity, but the specifics depend strongly on crop dominated system (thus improving food agroforestry, also agroforests of coffee, cocoa, local conditions (Sibhatu and Qaim, 2018). In availability and dietary diversity), alongside palm, fruit trees with secondary crops) re- Liberia, for example, food security is directly other policies targeting other parts of food ported having better food security than mon- linked to crops that farmers can gow (Fou- supply chains. Below, we summarize the oculture households (Fouladbash and Currie,

55 RUBBER AGROFORESTRY Livelihood outcomes

2015). The food security indices measured integration, this process is thought to have munity members, who are most dependent in the survey found that 22% of agroforest- improved food security and resulted in fewer on non-timber forest products for food and ry households ate three meals per adult per health and nutrition problems (van Noordwi- household income, were losing access to re- day, as compared to none of the monoculture jk et al., 2014). Indeed, the importance of cash sources due to forest conversion to rubber households; while 70% of agroforestry house- from rubber cultivation for increasing food monoculture. (see also Box 2 for full details holds reported that they always had enough security in some contexts is very considera- of the Lao PDR case study in section 3.1). to eat, compared to 31% of monoculture ble – in Sumatra, Indonesia, the switch from households (Fouladbash and Currie, 2015). A growing rice for subsistence to jungle rubber, In Indonesia, it is possible to purchase rice survey of smallholder farmers in Nigeria also or monoculture rubber, increased returns to grown elsewhere rather than needing to grow found that rubber agroforestry was adopted labor by four and 30 times respectively, offer- it within mixed systems when rubber prices to meet food and nutrition needs, and to in- ing far higher and more sustainable benefits are relatively higher than rice prices. Howev- crease household incomes, with intercrops to farmers than growing rice (Penot, 2004). er, smallholder farmers strongly recognize the including fruits and vegetables grown for However, the expansion of land use planning role of agroforests in providing food products consumption, high-value fruit crops and live- policy and government initiatives to avoid alongside rubber (for example rubber-rattan stock (including snails and bees) (Mesike, Es- shifting cultivation in Lao PDR, which has in- agroforests in Kalimantan, Indonesia, contain ekhade and Idoko, 2019). cluded the promotion of rubber plantations, fruit trees and other food crops that provide was reported by villagers to have decreased food security for farmers (Tata, 2019)). In Su- In Southeast Asia, it has been argued that food security (Ramcilovic-Suominen and matra, the conversion of jungle rubber agrofor- food security is no longer closely tied to lo- Kotilainen, 2020). Planting of monoculture ests to rubber monocultures suggests that not cal sufficiency of production, but has tran- rubber was considered to place food security only rice, but other components of diets are sitioned to market-based livelihood strate- at risk in Laos, particularly during the imma- bought at markets and therefore outsourced gies, where income security allowing access ture rubber phase before tapping could start to other locations. However, farmers in these to markets to purchase food is the primary to bring in income, as intercropping and in- landscapes also switch from agroforestry to driver of food security, even in remote places tegrating livestock into rubber plantations segregated land uses, e.g. growing vegetables/ (van Noordwijk et al., 2014). Rubber and oth- were strongly dissuaded by rubber compa- rice in plots separate from rubber monocul- er cash crops have been replacing traditional nies, who hold contracts with smallholders ture to maintain some food cultivation (van swidden (shifting) agriculture in mainland to plant and grow rubber (Haberecht, 2010). Noordwijk et al., 2014) (see also section 3.2.1). Southeast Asia; in places with greater market There was also concern that the poorest com-

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In Mindanao, Philippines, rice and mungbean forestry both through direct production, and An experiment from the Rubber Research In- intercropping in rubber has been adopted by increased cash income to spend on food at stitute of India found that annual vegetables some farmers, especially during the immature markets. Villagers living just outside the Sin- (Amaranthus and cucumber grew well) during phase (1-3 year old trees), with both products haraja Man and Biosphere reserve planted the leaf-shedding or wintering season in ma- sold at market and consumed directly (Hon- rows of rubber trees intermixed with a variety ture rubber plantations without affecting rub- drade et al., 2017). Agduma et al (2011) report of flowering and fruit trees (e.g. mango, papa- ber yield, and these vegetables can contribute that although the plantation company (Plati- ya, , ), tuberous crops and to part of household food needs (Jessy, Jo- num Rubber Development Corporation, Inc., climbing vines in “homegardens”; fifty-five seph and George, 2017). Makilala, North Cotabato, Philippines) do edible plant species were recorded in a sur- not plant high value intercrop species, there vey. The designation of the adjacent forest as Finally, even in the well-developed market is an area of agroforestry where additional a protected area meant that for villagers, food economies in Southern Thailand, old jungle plant species are used for food, medicine and procurement activities, such as shifting cul- rubber provides access to local and medici- sources of construction materials, fodder for tivation and collection of non-timber forest nal plants,34 and certain food crops in rubber livestock, fuel wood, source of fibre and other products and edible plants from the adjacent agroforests are planted for household con- industrial and household uses, by local com- forest became illegal. Homegardens therefore sumption, especially those that are less pro- munities - so these systems provide addition- became more important as a source of food ductive (e.g. mangosteen). Other food crops al non-market value, including food resources and cash income. However, families were not have higher commercial value and so are (Agduma et al., 2011). food self-sufficient, and the majority of fami- grown as cash crops (e.g. snake fruit, salak, lies in the village spent more than half of their cempedak).35 In Sri Lanka, there is evidence from a 1995 monthly income on food (Caron, 1995). study for improved food security from agro-

34 Email consultation, Bénédicte Chambon. 35 Interview, Sara Bumrungsri.

57 RUBBER AGROFORESTRY Social Outcomes

3.2 SOCIAL OUTCOMES

The changing dynamics and practices of rubber ernment incentives (Stroesser et al., 2018) or ularly mainland Southeast Asia (e.g. see Box cultivation in Southeast Asia, and elsewhere, changing market pressures (Drescher et al., 2, (Fox and Castella, 2013)). These histories have a complex history (Warren-Thomas, 2016). Food production has therefore been and contexts influence the social outcomes of Dolman and Edwards, 2015; Langenberger et spatially separated from rubber production in agroforestry practices in rubber cultivation. al., 2017). In some regions, such as Southern these regions for a long time, while monocul- Thailand and Indonesia, rubber cultivation ture rubber has improved household incomes To date, there have been very few published has been part of smallholder livelihoods for for many people in e.g. China, Thailand, and studies on the impacts of rubber-based agro- multiple generations. For example, see (Dove, Indonesia. However, concerns around wide- forestry on social, gender, or land tenure as 1993, 1994) for in-depth discussion on the his- spread land-grabbing, forced eviction, co- the literature has focused primarily on the tory and political economy of forest-dwelling ercion to produce rubber, and displacement agronomic, economic and environmental as- tribal smallholders in Borneo who have inte- of Indigenous communities and smallholder pects of rubber agroforestry. Here, we synthe- grated Hevea rubber into swidden practices. farmers from lands used to produce food, for size the most relevant information on the so- Agroforestry systems were historically pres- foraging, and areas of cultural and spiritual cial outcomes of rubber agroforestry from ent in these places, but have been replaced importance, have been raised in areas where the literature and from the interviews. with monocultures either in response to gov- rubber has expanded more recently, partic-

3.2.1 GENDER

Do rubber agroforestry Gender issues in agroforestry systems are im- making, farm labor and domestic workloads, portant to consider, because in many socie- tree planting, and participation in rural val- systems contribute to ties women and men have distinct roles and ue chains. This topic has been broadly ap- gender equity? preferences, for instance in land-use decision proached across all continents with a focus

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on the relevant laws, cultural and religious women in African agroforestry systems could trends, access to natural resources, norms increase their yields by 20-30% (FAO, 2011; of behaviour, access to education and funds, Kiptot, Franzel and Degrande, 2014). daily economic roles, demographic issues, domestic roles and power dynamics, and Specifically on rubber agroforestry systems, available economic alternatives (see (Colfer, very little peer-reviewed research has been Catacutan and Naz, 2015) and special issue published on gender equity and labor bur- therein). For example, in Africa, female farm- dens. Interviews with researchers suggested ers frequently manage trees in agroforestry that agroforestry could create more oppor- systems at the beginning, and also make up tunities for female participation, because it half of farm labor. However, women can face requires more family labor.36 Both men and many more restrictions than men to access women are thought to be involved in rubber land, labor, education, extension, financial farming and tapping (both monoculture and services and technology. Surveys have shown agroforestry) in Southern China, Thailand, that there are also gender differences in ‘tree Malaysia, and Indonesia.37 Women are more tenure’, whereby women may only have rights involved in selling intercrop or agroforestry to use less-valuable by-products such as products such as fruits, vegetables, and native branches, fodder and indigenous fruits. More- wildflowers.38 For example, in Thailand, wom- over, women only receive 5% of extension en form the majority of small-scale fruit and services. With access to the same resources, vegetable vendors at markets, and are more

36 Interview, Sara Bumrungsri. 37 Interviews, Rhett Harrison, Sara Bumrungsri, Uraiwan Tongkaemkaew, Michael B. Commons, and anonymous. 38 Interviews, Sara Bumrungsri and Uraiwan Tongkaemkaew.

Woman in Dawei, Myanmar is processing raw latex Credit: CC BY-NC 4.0 TCW

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likely to prepare food for the family, which tural preferences to increase female interest cal finding in studies and may be why most perennial vegetables and and participation in agroforestry that could REDD+ projects. Hecht (2007) criticised the other basic food plants within agroforestry offer additional benefits, including cash in- lack of attention paid to gender divisions of system are primarily managed by women.39 come. For example, in Nigeria, arable crops labor in extractive reserves in rural Amazon, This is consistent with observations from like melon, maize and cowpeas were tradi- and highlighted a failed development project the literature from Indonesia that men play tionally handled by women.42 Another exam- to promote rubber and extraction, a larger role in physical tasks, and women ple noted by a practitioner in Thailand was where women pulled out of the project be- contribute more to financial aspects (Villa- that of medicinal plants, which more closely cause their labor was required (and generat- mor et al., 2015). Where rubber trees are pri- resonates with traditional roles of women.43 ed better returns) in agricultural work. The marily managed by men, this may mean that To increase the interest of women in agro- authors also suggest that extractive reserves women could manage the intercrops.40 Some forestry, women-led training in potential can be effective for gender equity, but atten- intercrop options may be culturally or tradi- use of intercrops such as medicinal plants tion needs to be paid to where they are locat- tionally more attractive to women. However, was suggested.44 ed geographically (e.g. near areas with higher this depends on the existing demand placed densities of economic trees), and what roles on women’s labor, as in some contexts, such In a case study of wild rubber extraction in women play in labor. as Southern Thailand, women may already be an indigenous community in Peru, Fitts et heavily involved in rubber tapping and tree al. (2020) found that women were more in- In Jambi, Indonesia, surveys and role-play- management, alongside holding responsi- volved in forest management compared to ing games with farmers found differences in bilities for domestic management and care, other communities, but men’s voices were land-use preferences between females and and therefore have little additional labor to given more weight in decision making due to males (Villamor et al., 2014). In this land- spare.41 Rubber agroforestry strategies could traditions, language ability and knowledge of scape, a matrilineal inheritance system exist- thus be tailored to local gender roles and cul- the topic. They surmised that this was a typi- ed for rice paddies, whereas men could claim

39 Interview, Michael B. Commons. 40 Interview, Rhett Harrison. 41 Personal observation, Eleanor Warren-Thomas. 42 Interview, Kenneth Omokhafe. 43 Interview, Michael B. Commons. 44 Interview, Michael B. Commons.

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land rights by planting rubber trees. Most ber and men preferring to retain rice fields and other agricultural work which were tra- men tapped rubber while women grew rice. and jungle rubber (Villamor and van Noor- ditionally men’s responsibilities. They also In the role-playing games, women were more dwijk, 2016). The researchers suggest that it noted that women had relatively more re- likely than men to choose to convert jungle was important to involve women more di- sponsibility in managing farm finances com- rubber into other more profitable land uses rectly in information dissemination activities pared to the physical work. such as or oil palm monoculture. Men regarding the environmental values of forests preferred to retain blocks of forests and jun- and jungle rubber, to improve outcomes of Finally, Fouladbash and Currie (2015)’s sur- gle rubber for timber to use in building hous- projects designed to promote conservation of vey of tree-cropping households in Liberia es, whereas women preferred to retain only these systems. found no significant differences in gender jungle rubber to support water supplies for between household heads that practiced electricity, irrigation, and drinking, demon- Villamor et al. (2015) found that gender roles agroforestry (in the case of rubber farms, strating different values placed on ecosystem and perception of gender roles in Suma- this refers to temporary intercropping during services. Women also preferred a spatial sep- tra were shifting with land-use changes, as immature phase) and households that only aration between rubber and vegetable gar- rice-based swiddens and jungle rubber are practiced monoculture. However, they found dens, due to the risk of wild boar (that live converted to monoculture oil palm or rubber that female household heads were less likely in forest) damaging vegetable crops (see also production. While their findings were de- to practice tree cropping, which they found section 3.1.4). An exercise in a semi-matrilin- tailed and complex, they suggest that in the to be consistent with other studies in Libe- eal community in Sumatra revealed similar lowlands, where the largest shifts in land-use ria and across Sub-Saharan Africa. This could trends, with women more likely to convert systems have occurred, women are increas- have implications for uptake of agroforestry jungle rubber to economically profitable rub- ingly more involved in rubber agroforestry practices in the region.

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3.2.2 LAND TENURE

Do rubber agroforestry systems improve large companies transform forest into rubber plantations, as in land-grabbing in Cambodia land tenure security? (Schoenberger and Beban, 2018). Local peo- ple are, in some cases, only able to maintain Planting and managing trees can help confer of land for forestry than for agriculture (in their livelihoods because they are able to in- some form of tenure to the owner of a farm some countries rubber is classified as an ag- tercrop in the plantations and, hence, rubber plot. For example, in Sri Lanka, growing rub- ricultural crop and not timber). In these cas- agroforestry partly mitigates the negative ef- ber helps confer land tenure because rubber es, incorporating timber trees into farms will fects of lost land tenure (see also Box 2). trees provides a permanent and continuous improve land tenure security. However, some income (Rodrigo, Thenakoon and Stirling, smallholders may want to leave farming and, Rubber agroforestry may lead to forest clear- 2001). This means that despite low rubber hence, prefer shorter term or annual crops ing as happens with cacao agroforestry.47 For prices, some farmers still choose to plant over timber trees that will not tie them to the example, in Peru a lack of tenure security, gov- rubber, as the trees require little mainte- land. 46 In other words, longer leases of land ernment capacity to enforce encroachment nance can help improve land tenure security or land tenure is not always the preferred op- onto forested land, or, simply, because many for the entire farm system. Similarly, in Nige- tion of the farmers. smallholders have forests on their agricultur- ria, agroforestry involving permanent crops al land, agroforestry revenues could stimulate like rubber trees improved land tenure secu- Temporary intercropping in rubber planta- forest conversion into agroforestry plots. In rity compared to annual crops alone.45 tions allows villagers in Lao PDR to main- these cases, certification mechanisms may tain their livelihoods after involuntarily help to incentivize forest protection (Tschar- Similarly, intercropping rubber with timber losing land tenure to company investments ntke et al., 2015). can increase duration of land tenure, because (IUCN and NERI, 2011). In some locations, some national policies grant longer leases rural livelihoods are negatively affected when

45 Interview, Kenneth Omokhafe. 46 Interview, Rhett Harrison. 47 Email consultation, Julia Quaedvlieg.

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3.2.3 OTHER SOCIOCULTURAL BENEFITS Farmers in Southern Thailand reported The indirect role of attention from interna- flexible tapping schedules without affecting strong social benefits from rubber agroforest- tional researchers interested in agroforestry yields. This could make rubber tapping more ry practices, including teaching other farm- has also affected farmers in Southern Thai- amenable to women, as tapping at night can ers, sharing seedlings and secondary crop land.49 Researchers stated that farmers bene- be a safety concern, as well as increase the products, and participating in nationwide fitted from international researcher visits: in- quality of life for rubber tappers. However, agroforestry social networks (Theriez et al., ternational students stayed with farmers who this is so far unsupported by any empirical 2017, Kittitornkool et al., 2019). People who practise agroforestry to conduct research, evidence, and would need a much stronger planted fruits in rubber agroforests primarily which increases interest from other farmers, evidence based before it should be used as a did so for self-consumption, while the social bolstering farmer confidence in agroforestry. reason for wider adoption. See also section role of edible species was also emphasized It should be noted that this is unlikely to be a 3.3.1.3 on microclimates. in the Thai context (e.g. providing fruits to widespread or sustainable long-term benefit gift to others) (Stroesser et al., 2018). Agro- of rubber agroforestry. For wild rubber tapping, Brown and Rosendo forestry farmers in Thailand have additional (2000) found that while partnerships with opportunities: they have “better opinions and Agroforestry has the potential to allow for CSOs in Rondonia, Brazil, improved the po- are more creative”, report that agroforestry more flexible tapping schedules, enhancing litical empowerment of rubber tappers, they benefits others, and that additional revenues participation of women and quality of life did not improve livelihood conditions of the from agroforestry can be given to their chil- for rubber tappers.50 The reason for tapping poorest. dren.48 (See Box 3 on farmer autonomy and at night is that cool temperatures improves Box 4 on connecting networks for case stud- latex flow. Theoretically, rubber agroforest- ies of agroforestry farmer networks in South- ry can keep microclimates on farms cool- ern Thailand). er, which could potentially allow for more

48 Interview, Uraiwan Tongkaemkaew. 49 Interview, Uraiwan Tongkaemkaew. 50 Interview, Michael B. Commons.

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BOX 3 FARMER AUTONOMY IN A FARMER NETWORK-INDUSTRY PARTNERSHIP, SONGKHLA PROVINCE, THAILAND 51, 52

The agroforestry farmer network in Songkhla other species in their rubber plots, including not ing with their condom manufacturer (Richter began as a group of farmers who had a com- just timber trees but also bushes and herbs, or Rubber) to market the sustainable latex to mon passion for planting trees from seed- integrating bees or other animals. other companies. lings that were being given out for free from the Royal Forest Department. A local university Members of this farmer group have also learned This farmer network – industry partnership researcher became involved when the group to measure the dry rubber content in latex and model based on the participatory guarantee invited the researcher to give a lecture on agro- assess latex quality themselves, and so do not system seems to be working well thus far. Eco- forestry. They were subsequently approached have to rely on middlemen. They manage an nomically, it has helped by securing a price by Einhorn, a condom company based in Ger- independent group latex collection point, premium and direct access to processors for many, who were looking to directly source latex from which their latex is picked up by the pro- their rubber latex. Socially, the farmers have produced via fair and sustainable means. cessor, and the farmers receive a premium for increased autonomy, and they show enthusi- the latex they send. asm and pride in their work and how their ideas Facilitated by two local consultants, this group are being spread to others. The Royal Forest of about 35 agroforestry farmers came up with Additionally, the agroforestry farmers are also Department also supports the farmers’ travel a common vision for how they wanted to work collecting information on the species in their to other regions in Thailand for meetings and with each other and with Einhorn, which was agroforestry plots and on different intercrop- trips, during which farmers meet other farmers formalised as a participatory guarantee sys- ping ideas, working closely with researchers to exchange ideas. Farmer networks will con- tem. The participatory guarantee system is an from Prince of Songkhla University in Hat Yai, tinue to benefit from the latest knowledge in arrangement where the farmers themselves Thailand. farming practices and support to further devel- define their own standards and regulations for op their business models, especially in terms of being part of the group. For example, they have Currently, Einhorn purchases about 30-35% managing and marketing agroforestry products agreements on the usage of agro-chemicals, or of the agroforestry farmers’ latex output for other than rubber latex. agroforestry criteria such as having at least 30 their condom production, but they are work-

51 Interviews, Linda Preil and Sara Bumrungsri. 52 YouTube video about Einhorn’s project: https://www.youtube.com/watch?v=VY1k-1looc4

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BOX 4 CONNECTING AGROFORESTRY FARMER GROUPS IN PHATTALUNG PROVINCE, THAILAND53

In Phattalung province in Thailand, adoption of reasons for joining a group/network, the most the researchers studied the feasibility of mo- agroforestry practices originated from individ- frequent answer was to share knowledge or to bilising current agroforestry networks to set ual pioneer initiatives that spread more wide- learn about agriculture, and the next most fre- up an agroforestry innovation platform, which ly through farmer-to-farmer networks (Thaler quent was access to government support. would better connect farmer groups with each et al., 2019). The smallholder farmer network other, and with other stakeholders involved in was reportedly initiated around common val- Within the networks farmers shared informa- the promotion of agroforestry practices. Re- ues (local species preservation, increase of tion, such as the plants they used in their agro- searchers also proposed the possible orga- farmers’ income) with the objectives of bet- forestry systems, and also worked together to nization of a regional innovation platform to ter access to funding and knowledge sharing. market the products. Researchers from CIRAD co-construct and encourage the adoption of Farmers appeared motivated to join collective and Thaksin University worked together with innovative agroforestry systems. The challenge action by incentives such as access to funding these rubber agroforestry smallholders. With now is to convince Thai institutions to take the or to activities organized by local government the aim of scaling-up rubber agroforestry sys- leadership to initiate such a platform. agencies. When farmers were asked about their tems from a marginal to a widespread system, See also Theriez, M. et al (2017)

53 Interview and email consultations, Uraiwan Tongkaemkaew and Bénédicte Chambon.

3.3 ENVIRONMENTAL OUTCOMES

This section addresses a number of inter- topics is strongly integrated with livelihoods, linked issues around the sustainability of rub- yields and pests and diseases that have been ber cultivation, in terms of climate resilience, covered earlier in the report, but also relate climate mitigation, soils, water use, ecosys- to the global challenges of global heating and tem resilience and biodiversity. Each of these the extinction crisis.

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3.3.1 CLIMATE RESILIENCE OF AGROFORESTRY Do rubber agroforestry systems offer smallholder farmers climate adaptation potential and greater resilience to the effects of climate change?

Concerns have been raised that rubber is land, there are increasing concerns that cli- being established in increasingly marginal mate change induced changes to weather sub-optimal environments, i.e. those where patterns may increase risks of disease and rubber tree stress or death is likely due to drought stress, potentially impacting rub- drought, cold, wind damage or soil erosion, ber yields (Neo, 2020). and that climate change is likely to exac- erbate risks to rubber cultivation in future Although agroforestry systems are touted as (Ahrends et al., 2015). Although this analy- win-win solutions for productivity, climate sis acknowledges considerable uncertain- resilience and ecosystem services includ- ties, the study estimates that marginality ing climate mitigation (i.e. carbon storage), will be exacerbated by climate change for evidence from cocoa and coffee agroforest- up to 69% of current rubber area in sub-op- ry shows that there are trade-offs between timal locations (as defined in their study). these benefits. Both crops grow in the shade Meanwhile, within highly suitable areas for of canopy trees, whereas rubber trees form rubber cultivation, such as Southern Thai- the canopy, so conclusions are not directly transferable, but findings from these sys- tems are informative. Coffee agroforestry Rubber-cocoa intercropping in systems can limit precipitation and drought Bahia, Brazil impacts on coffee compared to non-shaded Credit: CC BY-NC 4.0 TCW

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plantations and, hence, could avoid income has been rebutted due to major methodolog- the surface in both monocultures and jungle losses (Tscharntke et al., 2011b). Recent ical flaws (Wanger et al., 2018b). If cocoa and rubber (Hardanto et al., 2017). Several studies studies from West Africa show that cocoa coffee systems can be considered a surrogate assessed whether intercropping can enhance agroforests with low- to medium shading for rubber, agroforestry systems may support water use efficiency and drought tolerance of created multiple benefits, including climate climate-resilient rubber production. This is rubber. Overall, the literature shows that in- resilience, while maintaining production, congruent with thinking from Nigeria, where tercropping rubber with other plants can but that once shading increased above ~30%, rubber trees are noted for their resilience and improve soil water retention across the win-win scenarios were less likely, with low maintenance costs which makes them whole system, although outcomes for wid- trade-offs appearing (Blaser et al., 2018). suitable for agroforestry.54 Evidence around er-scale hydrology are unclear. This work showed that while more shad- rubber-specific climate resilience is summa- ed systems (i.e. more complex agroforests) rized in this section. Rubber trees in jungle rubber adapt by tak- could buffer some climate extremes (heat, ing up water from deeper soil layers, while drought, humidity) in some seasons, there 3.3.1.1 WATER USE AND rubber trees in monoculture mainly take were also negative effects, such as decreases DROUGHT TOLERANCE up water from layers closer to the surface. in soil moisture in other seasons. Similarly, In Sumatra, this pattern was because na- in smallholder coffee systems in Ethiopia, Water use of rubber cultivation systems is of tive trees would take water from shallower farmer incomes declined by ~70 – 80% in considerable concern because rubber is often layers (Hardanto et al., 2017). In Xishuang- the 2015/16 El Niño year relative to previous planted in locations with long dry seasons banna, China, water use efficiency of rubber years, and farmers with greater shade cover (Ahrends et al., 2015), increasing the risk that trees in jungle systems was more stable (i.e. suffered most due to a combination of biotic climate-related drought events could impact more even water uptake across wet and dry and social factors (Morel et al., 2019). A study production. Rubber is a drought-avoidant seasons) than in monoculture, and jungle from Ghana suggesting that cocoa mono- plant with strong water uptake plasticity rubber has higher soil water content than cultures are advantageous to reduce climate and it can avoid interspecific competition monocultures in both wet and dry seasons, change impacts compared to agroforestry by adapting which soil layers it takes water demonstrating that rubber trees in jungle system due to water competition between from (Wu, Liu and Chen, 2016b). Larger (old- rubber would be more tolerant to drought cocoa and shade trees (Abdulai et al., 2018) er) rubber trees tend to absorb water closer to stress (Zeng et al., 2019).

54 Interview, Kenneth Omokhafe.

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Rubber cover-cropping with legumes in In Xishuangbanna, China, water usage was soil moisture, increase deeper drainage and drought-prone areas has been shown to have more efficient when rubber trees were inter- recharge groundwater (Zhu et al., 2019). mixed effects on climate resilience. A study cropped with tea or coffee but not cocoa (Wu, in northeast Thailand examined the effects of Liu and Chen, 2016b). It has been suggested two cover crops (a legume Pueraria phaseoloi- that crops selected for rubber intercropping “Rubber did not compete for des and a grass Vetiveria zizanoides) on the roots should have a “relatively fixed water use shallow soil water resources of young rubber trees, to assess whether they pattern, short lateral roots and a moderate improved drought resilience. In shallow soils, amount of fine roots that overlap with the with tea, cocoa and galangal rubber trees cropped with the legume grew roots of the rubber trees in the shallow soil intercrops.” faster, had higher leaf nutrients, and more fine layer” (Wu, Liu and Chen, 2016b). Tea and roots in deep soil layers than monocultures, coffee showed drought-tolerance strategies but rubber trees cropped with grass had no enabling them to compete for surface soil In contrast, a year-long study showed that such effect. Trees with cover crops benefited water. Tea was the best intercrop in terms rubber did compete for shallow soil water from increased water extraction in deep soils. of water use because moderate interspecific resources with tea, cocoa and galangal inter- The authors suggest intercropping with the le- competition helped the soil retain water (Wu, crops during the dry season, as all species pri- gume may increase drought resistance in young Liu and Chen, 2016b). But in terms of rooting marily used water from the topsoil (0-20cm) rubber trees, but might not reduce drought-in- depths, cocoa, the legume F. macrophylla and (Yang et al., 2020). However, intercropping duced tree mortality (Clermont-Dauphin et al., rosewood (D. cochinchinensis) were prefera- also increased the available soil water, such 2018). This result came from an earlier study ble over coffee because the former intercrops that rubber trees acquired more water from which found that in some plots where soils have most of their fine roots in the topsoil the topsoil than when in monocultures. had low water storage capacity, rubber trees (Chen et al., 2017). Other rubber-tea studies with the legume cover crop were less likely to confirmed that rubber and tea used water Shallow rooted medicinal herbs (Amomum vil- survive intense drought despite having better from different soil layers (Wu, Liu and Chen, losum and Clerodendranthus spicatus) may also nutrient content and growth (Clermont-Dau- 2017). Soil around tea rows contained more help mature rubber trees use deeper soil water phin et al., 2016). In China, the legume cover water than other parts of the plantation, alle- during the dry season (Wu, Zeng, Chen and crop (Flemingia macrophylla) and rubber used viating soil drought on rubber terraces (Wu, Liu, 2019). Five years after establishing inter- different soil layers, increasing water use effi- Liu and Chen, 2017), while greater soil water crops with these herbs, more water was trans- ciency and drought tolerance of rubber (Wu, infiltration around the tea shrubs may help ported, redistributed and stored in different Liu and Chen, 2016). reduce runoff and soil erosion, redistribute soil layers (Jiang et al., 2017). However, there

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FARMERS’ was no improvement in water use efficiency or 3.3.1.2 ed by communities (also: crop diversification PERCEPTIONS OF CLIMATE soil water in these systems relative to mono- (64%), crop substitution and calendar redef- RESILIENCE cultures (Wu, Zeng, Chen and Liu, 2019). inition, agroforestry, borrowing from friends Rubber farmers in multiple locations report and money lenders, and increasing fertilizer Studies of intercropping effects on water use concerns around climate change and con- application) (Yeo et al., 2016). from other locations are harder to find, but sider agroforestry as an adaptation or mit- a comparison of rubber monocultures with igation strategy, although no studies investi- In Southern Thailand, droughts and extreme intercrops of coffee, vanilla, Garcinia and gated whether these perceptions were based rain are becoming more frequent, resulting in nutmeg in India showed that soil moisture on observations. A structured survey ques- the deaths of rubber trees, and reductions in status during summer was higher in mixed tionnaire survey of 623 farmers in Mindan- rubber yields. Trees tapped during droughts planting systems compared to monocultures, ao, Philippines, found that farmers perceived are reported to have reduced productive while soil nutrient status was maintained drought (El Nino), typhoons, strong winds, lifespans, while trees tapped during unusu- (Jessy, Joseph and George, 2017). Finally, a heavy rains/excessive rainfall, flash floods and ally humid conditions raises the risk of fun- study comparing a mature rubber monocul- landslides to be evidence of climate change, gal diseases (Phytophthora), both of which ture (20 years old) with an adjacent agrofor- and identified agroforestry and diversified reduce rubber yields and farmer incomes est (20-year-old rubber + 10-year-old bamboo farming systems as effective adaptation strat- (Neo, 2020). Agroforestry practices may in- in the inter-row) in southern Thailand found egies (Furoc-Paelmo et al., 2018). In Cote crease humidity and water availability on no evidence for root or water competition be- d’Ivoire, 384 people were surveyed about cli- farms during droughts, potentially mitigating tween rubber and bamboo roots. The authors mate change and water impacts using focus the effects of climate change on rubber yields suggest that although bamboo uses a lot of groups, interviews and questionnaires. 95% of in this region. It is also argued that reducing water, especially from the topsoil, its greater respondents were aware that climate change soil erosion and improving soil moisture and root density in the topsoil may actually in- was occurring, reporting changes in econom- organic matter through agroforestry practic- crease the water-holding capacity of soils, as ic activity (e.g. income losses) and cropping es (evidence for which is provided in section found in other studies on bamboo, as well as patterns (e.g. crop failures, yield losses, delays 3.3.3 of this report) can improve rubber tree providing additional organic matter through in cropping season, new pests and diseases) health and provide secondary agricultural leaf litter that can improve soil structure (An- and food insecurity (Yeo et al., 2016). Agro- products for consumption or sale and, hence, driyana et al., 2020). forestry (55% of people) was among various reduce risks from reduced rubber yields (Neo, adaptation strategies to these changes report- 2020), see section 3.1.1).

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3.3.1.3 MICROCLIMATE ENSO event was similar to monoculture, er (i.e. monoculture) systems, because this indicating that although jungle rubber had could have knock-on effects for soil nutrient There is some evidence that rubber agro- more stable microclimate in normal years, fluxes and nutrient use efficiency. Leaf litter forestry can buffer the effects of normal it could not buffer the effect of ENSO in the fall was highly seasonal in rubber monocul- fluctuations in microclimate, but there is same way as natural forest. As jungle rubber tures in response to rainfall, but was much currently little evidence that they could do reached comparable temperatures, humidity more even throughout the year in jungle so during climate change-induced extreme and vapour-pressure deficit as in monocul- rubber (similar in quantity and temporal weather events. Air temperature was lower tures during the ENSO event, despite having (by ~0.5oC) and relative humidity was higher cooler and more humid conditions in normal (by ~5%) in jungle rubber than monocultures years, this suggests that jungle rubber systems “Diversified agroforestry (Drescher et al., 2016). However, a three- are still vulnerable to extreme climatic events systems may therefore have year study of microclimates in forest, jungle (Meijide et al., 2018). Overall, climate change rubber and monoculture rubber in Sumatra, related impacts are buffered in agroforestry benefits for resilience of which included the strong 2015 ENSO (El systems by introducing shade trees. In rubber nutrient cycling the face of Niño) event, found that jungle rubber main- intercropping, rubber trees provide shade to tained more stable microclimate (in terms other crops and, hence, positive effects can be climate change.” of air temperature, soil temperature, relative expected for the overall system instead of just humidity and vapour-pressure deficit) than for rubber trees. pattern to natural forest) where it happened monoculture rubber, although not as stable irrespective of rainfall. The results suggest as forests. This was mostly due to increased Nutrient cycling may be affected by climate that nutrient and carbon cycles are more canopy cover. The relative effect of the ENSO change, by altering the seasonality of nutri- directly affected by climate seasonality in event (reduced rainfall, increase tempera- ent inputs. The seasonality of leaf litter fall, species-poor agricultural systems than in tures) on below-canopy microclimate vari- root litter and above-ground woody biomass more species-rich systems, and may be more ability was smaller in monocultures than in production was compared between jungle susceptible to inter-annual climate fluctua- forests because they were already more simi- rubber (where 35% of tree individuals were tions and climate change (Kotowska et al., lar to open areas (e.g. already showing strong rubber), monocultures and rubber, to as- 2016). Diversified agroforestry systems may daily fluctuations in temperature). Changes sess whether temporal fluctuations in litter therefore have benefits for resilience of nu- in microclimate of jungle rubber during the inputs were more intense in species-poor- trient cycling in the face of climate change.

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3.3.2 CLIMATE MITIGATION THROUGH CARBON SEQUESTRATION Do rubber agroforestry systems better sequester carbon? What role can rubber agroforestry play in climate adaptation and mitigation for industrial plantations?

We provide an overview of how carbon stock tems. While strongly context and tree density and sequestration are measured in the con- dependent, data on rubber carbon balances text of rubber monoculture plantations and showed that when considering monoculture rubber agroforests, which is important for rubber plantations, net carbon sequestration understanding how to compare carbon out- (sinks/draw-down) occurs after conversion of comes between the systems. Differences in arable land to rubber plantations, but carbon former land cover/land uses and the long- emissions (losses) occur if natural forest is term destiny or end-use of the trees (in both converted to rubber. Therefore, clearance of systems) complicate such comparisons. In natural forest, or permanent jungle rubber general, incorporation of additional plant agroforestry systems (that are not felled on species into rubber systems will increase a cyclical basis) will always have a net neg- above-ground biomass, and therefore in- ative impact on carbon emissions and cli- crease carbon storage in agroforestry sys- mate change.

Vegetation growing in shade in natural regeneration under rubber, Malaysia Credit: CC BY-NC 4.0 MSHW

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CARBON ACCOUNTING 3.3.2.1 in a typical rubber plantation cycle, trees are What happens OF RUBBER SYSTEMS – planted, sequester carbon through growth ESSENTIAL KNOWLEDGE to the trees after over the plantation cycle, and are then felled The carbon stock of a rubber plantation, or after 25-30 years. Carbon stocks not only felling is critical agroforest, is more difficult to measure than change throughout the duration of the plan- it may appear. Trees can help mitigate climate tation cycle, but what happens to the trees to whether the change by extracting carbon from the atmos- after felling is critical to whether the carbon phere as carbon dioxide, and laying it down stored in trees can be considered a long-term carbon stored in a stored form (carbon sequestration); car- carbon sink, or whether the carbon will just bon stocks are a measurement of the carbon be re-emitted. For example, rubber trees des- in trees can be stored in trees. However, the long-term desti- tined for the timber trade may be used for ny of the carbon stored in trees in any system construction or furniture, meaning much of considered a (forest or plantation) must be considered, i.e. the carbon in the tree remains out of the at- what happens once trees are felled at the end mosphere, or they may be used as firewood, of a plantation cycle. If felled rubber trees are or burned in-situ, resulting in re-release of long-term carbon destined for paper or pulp, the carbon stored stored carbon back to the atmosphere. A full in them is likely to be re-emitted when these life-cycle assessment of rubber-based prod- sink.” products break down/decompose over time. ucts, including timber products, would be Alternatively, if the trees are used as timber, needed to fully quantify net carbon outcomes. at least a proportion of carbon in the trees However, in the case of converting a system can be considered to be in a long-term or per- with permanent tree cover (such as a forest, manent stored state, offering benefits for cli- or agroforestry systems that permanently mate change mitigation. retain tree cover such as jungle rubber) to a cyclical plantation (such as a rubber mono- In the case of rubber plantations, estimates culture or permanent intercropping within of the above-ground carbon stock of trees can a normal 25-year rotation), there is usually a be made through tree measurements – these net emission of carbon. represent the amount of carbon stored by the trees at any one point in time. However, Similarly, across a landscape, rubber planta-

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tions (whether monocultures or agroforests) There is strong evidence for soil carbon re- traction from the trees. A study from south- will be of different ages. So, when calculating ductions when forest is converted to rubber ern Thailand calculated that greenhouse the potential carbon stock of a whole land- (Blagodatsky, Xu and Cadisch, 2016) or oth- gas emissions of fresh latex were between

scape or region, a measurement of the max- er tree cash crops (Van Straaten et al., 2015), 56-169g CO2 kg fresh latex depending on imum carbon stock of a mature rubber plan- but the Intergovernmental Panel on Climate farm size (Usubharatana and Phungrassa- tation cannot simply be multiplied across the Change (IPCC) tier 1 carbon outcome calcu- mi, 2018). The same study suggests that area of interest. Instead, the different ages of lation method assumes no SOC change with the carbon footprint of latex rubber gloves plantations, and the cyclical nature of grow- forest conversion to perennial tree crops, so is independent of farm size but is primari- ing and felling, must be taken into account. this is not always taken into account (War- ly driven by chemical fertilizer inputs in the ren-Thomas et al., 2018). farms. Hence, rubber agroforestry practices This is why when assessing the carbon out- that reduce the use of chemical fertilizers comes of land use change involving cyclical For rubber monocultures in Southeast Asia, a should reduce greenhouse gas emissions in plantations, the carbon accounting methods robust time-averaged carbon stock estimate the rubber glove production supply chain. recommended in the IPCC Good Practice for rubber is 52.5 tC per ha; this is based on The study also demonstrates that latex ex- Guide recommend the use of time-averaged multiple estimates of taCs calculated either traction should be accounted for carbon carbon stocks (taCs) which give the mean as the carbon stock in the median year of the stock calculations. (average) or median (middle) value for the plantation cycle using logistic or Gompertz carbon stock over a plantation cycle, from models of growth, or 50% of the carbon stock Together, these issues mean that the benefits planting to felling. By doing this, carbon stock in the final year of the plantation cycle assum- that rubber agroforestry can offer from a estimates can be scaled up from a single plot ing a linear biomass increase (Blagodatsky, climate change mitigation perspective re- or farm to the landscape level, accommodate Xu and Cadisch, 2016). However, the max- quire careful thought. The factors outlined clearance and carbon release at the end of the imum carbon stock achieved will be greater in this section need to be understood, in order crop rotation, and better reflect the net car- than this, e.g. 128.4 MgC ha-1 for plantations in to accurately predict the outcome of adopting bon outcomes and long term climate impact Thailand (Petsri et al., 2013). agroforestry practices on carbon drawdown of a transition from one steady-state land use (sequestration) and storage (stocks) – pro- to another (Warren-Thomas et al., 2018). Lastly, carbon stock calculations are - cesses which can deliver benefits for climate ther complicated by continuous latex ex- change mitigation.

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BOX 5 CARBON POOLS AND CARBON DIOXIDE

Natural systems contain a range of carbon Soil carbon is held in organic matter in the soil. BOX 6 pools including: It has the longest lifetime if it is undisturbed CARBON UNITS AND • Above-ground biomass (i.e. it takes a very long time to decompose and release carbon dioxide) and therefore not only DEFINITIONS • Below-ground biomass reflects current conditions, but also historical • Soil carbon land use. Carbon stored in living organisms or the soil

• Leaf litter/dead wood (C) can be converted to carbon dioxide (CO2) • Rubber latex Latex collected from rubber trees should also using a conversion factor of 3.76; therefore, be accounted for, as this harvest removes bio- any measure of carbon (C) can be convert- ed to carbon dioxide equivalents (CO e) by Above-ground biomass (AGB) is the mass mass from the rubber plantation system, and 2 of the live portion of plants above ground (i.e. represents a long-term carbon sink, as rubber multiplying by 3.76, and vice versa. excluding roots), which is assumed to contain goods tend to have long lifespans (although 50% carbon (above-ground carbon, AGC). This production processes require carbon-emitting One metric tonne (1 t, 1000 kilograms) of includes rubber trees, understory plants, and technologies and transport, meaning a life-cy- carbon can also be written as a one mega- any secondary crops or trees. cle assessment approach may be needed to ful- gram (1 Mg). Therefore, 1 tC = 1 MgC = 1000 kgC, which approximately equal ≈ 3.76 t CO e. ly account for this). 2 Below-ground biomass (BGB) is the mass of the live portion of plants below ground (i.e. Total carbon stocks in plantations depend on root structures). This is rarely measured, and three main factors: is often assumed to be a proportion of above- • plantation age ground biomass (e.g. 0.24, or 24% of measured • plantation management, including tree AGB (Warren-Thomas et al., 2018)). density; latex tapping and fertilization

Dead wood and leaf litter are assumed to • environmental and edaphic (soil) eventually release its stored carbon into the at- conditions controlled by the local climate mosphere as carbon dioxide as it decomposes; and topography these generally form a much smaller part of the total carbon pool.

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RUBBER VS NON- 3.3.2.2 A review of rubber carbon balances also RUBBER LAND USES “Net carbon sequestration showed that when considering monoculture The net carbon outcomes of rubber planta- rubber plantations, and using time-averaged occurs after conversion tion or agroforestry establishment from the carbon stocks, net carbon sequestration oc- of arable land to rubber perspective of land cover change, strong- curs after conversion of arable land to rubber ly depend on the former land cover. A me- plantations, but carbon emissions usually plantations, but carbon ta-analysis of carbon outcomes of multiple occur if natural forest is converted to rubber emissions usually occur if land use transitions in mainland Southeast (Blagodatsky, Xu and Cadisch, 2016). Local Asia showed that outcomes are very con- climate conditions, soil properties, and to- natural forest is converted to text dependent, particularly when they in- pography all strongly affect carbon outcomes. rubber.” volve shifting agriculture (Ziegler et al., The carbon sequestration potential of any 2012). While allowing forest to regenerate rubber systems is less at higher elevations on cropland increases net carbon sequestra- (300 – 1000 metres above sea level) and in tion (positive), and converting forest into drier conditions (i.e. anywhere that tree the pre-existing land use. If the pre-existing cropland leads to net carbon losses (neg- growth is reduced) than at lower elevations land use has a higher carbon stock than rub- ative), the carbon outcomes are uncertain with greater precipitation. Planting density ber agroforestry (for example, if a rubber-in- when converting from swidden (especially of rubber trees strongly determines carbon tercrop system replaces natural forest or a long-fallow systems) to cash-crop-orient- stocks, and planting density tends to decline permanent jungle rubber agroforest), there ed systems, such as monoculture rubber. over time as trees die due to pests or wind may be net emissions of carbon, contributing In some cases, lengthening the fallow pe- damage, or through of weak trees as to climate change. In contrast, if the pre-ex- riods of existing swidden systems may in- reported in Sri Lanka (Blagodatsky, Xu and isting land use has a lower carbon stock (for crease carbon sequestration and storage, as Cadisch, 2016). Together, this means that example, if a rubber-intercrop system replac- would conversion from intensive farming to when looking towards the future, the net out- es annual cassava crops), there may be net high-biomass plantations and some types of come of rubber agroforestry adoption for sequestration of carbon, helping to mitigate agroforestry (Ziegler et al., 2012). carbon sequestration will be affected by climate change.

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CARBON 3.3.2.3 (root, soil, litter, dead wood, and above- trees and physically measuring, rather than SEQUESTRATION AND ground biomass) in Kalimantan, Indonesia, using allometric equations to measure car- STORAGE IN DIFFERENT increased with age, with 50-year-old rubber bon stocks based on tree diameter) (Brahma RUBBER SYSTEMS gardens actually storing more carbon than et al., 2018). This showed that carbon losses In general, the addition of more plant biomass [logged] secondary forests, but younger rub- due to clear-felling of mature rubber planta- to a rubber plot will increase carbon stocks of ber gardens contained less carbon, although tions was estimated at 135 Mg C ha−1. The au- the mature system. For example, in the Co- still more than cocoa-dominated-rubber-ba- thors suggest that lengthening the plantation lombian Amazon, rubber monocultures had a nana agroforests (developed from former cycle (e.g. to 40 years) could be beneficial by greater above-ground biomass carbon stock rubber gardens). Deep soil carbon storage retaining carbon stocks for longer, citing evi- than rubber-cupuaçu (a , related to (up to one metre depth) exceeded that of dence that rubber yields remained high until cocoa) agroforests, due to a higher planting above-ground biomass carbon in all sys- density of rubber trees in monocultures (Or- tems, and was stable among all systems juela-Chaves, Andrade C and Vargas-Valenzu- i.e. although above ground biomass carbon “Lengthening the plantation ela, 2014). However, carbon outcomes at stock changes over time with land use and cycle (e.g. to 40 years) could be wider temporal and spatial scales depend tree growth, deep soil carbon remains stable on longer term management decisions, such (Borchard et al., 2019). beneficial by retaining carbon as clearance versus selective replanting and stocks for longer.” planting cycle length. We summarize esti- A study in India outlined strategies to en- mates of carbon stocks in different rubber hance carbon stocks in rubber systems, in- systems in Table 2. Systems with greater car- cluding increasing cycle length (i.e. delaying 40 years; they also suggest that selective fell- bon stocks mean the system has drawn more felling and replanting), selective replanting ing of 20% of trees each year from 35 years carbon dioxide down from the atmosphere, instead of clear felling (see also section 3.1.1.2 to 45 years could be an alternative manage- which is beneficial from a climate change mit- on economic analysis of selective felling) ment strategy for maintaining carbon stocks igation perspective (please also see Section and retaining tree cover by using agroforest- during the replanting phase, or that agrofor- 3.3.2.1 for important caveats to this). ry. The carbon stock of 35-40-year-old rub- estry methods to retain tree cover should be ber trees in North East India was measured promoted to avoid carbon losses at the clear In jungle rubber systems, total carbon stocks via destructive sampling (cutting down the felling stage.

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Lastly, evidence from other agroforestry sys- ry forests. Greenhouse gas emissions can be omass in a rubber plantation will increase the tems is also informative. In general, cocoa reduced in cocoa agroforestry systems by total above- and below-ground biomass and agroforestry systems have been shown to reducing chemical fertilizers, from which carbon stock of that system relative to a mon- increase carbon storage, reduce greenhouse nitrogen is converted into nitrous oxide, the oculture. However, the net outcome in terms gas (GHG) emissions and mitigate climate third most important greenhouse gas after of carbon dioxide depends on the former land change effects. Carbon storage can be in- carbon dioxide and methane (Tscharntke et use, long-term management of plots, and the creased via enhanced shade cover by standing al., 2011b). eventual destiny of products within the agro- biomass; while soil organic carbon stocks of forestry system. cocoa agroforests can be similar to prima- In summary, inclusion of additional plant bi-

TABLE 2 CARBON STOCKS OF DIFFERENT RUBBER SYSTEMS ADAPTED AND EXTENDED FROM (BLAGODATSKY, XU AND CADISCH, 2016)

Accounting method: Time-averaged stock is a method to account for are left in perpetuity, such as in permanent jungle rubber agroforestry the cyclical nature of rubber tree planting and felling, recommended by systems. the IPCC (please see Section 3.3.2.1 for a detailed explanation of this); maximum stock is the maximum carbon stock recorded in a mature sys- Carbon pools: AGB = Aboveground biomass, means carbon content in tem towards the end of a plantation cycle, which can be a problematic all parts of living plants that are above the ground, such as wood, leaves, metric for plantation systems where trees are felled and the destiny of branches, etc.; BGB = Below Ground Biomass means carbon content in all the carbon in the trees is unknown (Section 3.3.2.1), but is useful if trees parts of living plants that are below the ground, such as roots.

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TABLE 2 CARBON STOCKS OF DIFFERENT RUBBER SYSTEMS ADAPTED AND EXTENDED FROM (BLAGODATSKY, XU AND CADISCH, 2016)

CARBON ROTATION TREE SYSTEM STOCK ACCOUNTING CARBON LENGTH DENSITY (see Table 1.1 for MG C HA-1 METHOD POOLS (YEARS) PER HA complete definitions) LOCATION SOURCE 46.2 (57.3) Time-averaged stock AGB (+ BGB) 30 NA Jungle rubber – rotational Indonesia (Blagodatsky, Xu and Cadisch, 2016) 23.0 Time-averaged stock AGB + BGB 15 500 Monoculture Brazil (Blagodatsky, Xu and Cadisch, 2016) 38.2 Time-averaged stock AGB 30 No data Monoculture Indonesia (Blagodatsky, Xu and Cadisch, 2016) 40.4 Time-averaged stock AGB + BGB 30 variable Monoculture Sri Lanka (Blagodatsky, Xu and Cadisch, 2016) 41.7 Time-averaged stock AGB + BGB 20 500-680 Monoculture Thailand (Blagodatsky, Xu and Cadisch, 2016) 42.0 Time-averaged stock AGB + BGB 20 500 Monoculture Indonesia (Blagodatsky, Xu and Cadisch, 2016) 42.4 Time-averaged stock AGB + BGB 25 No data Monoculture China (Blagodatsky, Xu and Cadisch, 2016) 43.2 Time-averaged stock AGB + BGB 30 Variable Monoculture Sri Lanka (Blagodatsky, Xu and Cadisch, 2016) 45.3 Time-averaged stock AGB + BGB 30 375 Monoculture China (Blagodatsky, Xu and Cadisch, 2016) 47.0 Time-averaged stock AGB + BGB 40 No data Monoculture Indonesia (Guillaume et al., 2018) 51.2 Time-averaged stock AGB + BGB 35 469 Monoculture Brazil (Blagodatsky, Xu and Cadisch, 2016) 63.7 Time-averaged stock AGB + BGB 25 419 Monoculture Thailand (Blagodatsky, Xu and Cadisch, 2016) 65.1 Time-averaged stock AGB + BGB 38 450 Monoculture China (Blagodatsky, Xu and Cadisch, 2016) 89.0 Maximum stock AGB + BGB NA NA Jungle rubber - permanent Indonesia (Palm et al., 1999) 75.2 Maximum stock AGB + BGB NA NA* Jungle rubber – permanent Indonesia (Guillaume et al., 2018) 61.8 Maximum stock AGB No data No data Rubber – cocoa intercrop Indonesia (Santhyami et al., 2018). 322 Maximum stock AGB NA No data Wild rubber Brazil (Salimon et al., 2011) 105.7 Maximum stock AGB + BGB 30-40 No data Monoculture India (Brahma, Nath and Das, 2016) 128.4 Maximum stock AGB + BGB 25 No data Monoculture Thailand (Petsri et al., 2013) 143.1 Maximum stock AGB + BGB 35-40 No data Monoculture India (Brahma et al., 2018) 214 Maximum stock AGB 44 No data Monoculture Ghana (Kongsager, Napier and Mertz, 2013)

*Rubber trees comprised 21% of tree biomass.

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Rubber 3.3.3 SOIL HEALTH AND WATER MANAGEMENT management should aim to Do rubber agroforestry systems promote better soil health and water management compared with maximise rainwater monocultures? penetration whilst Soil and water management feeds back nutrient export with yield products i.e. rub- meeting biodiversity directly to farmer livelihoods by effects ber tapping; thus there is a need for ferti- conservation and on yields (section 3.1.2), the costs of inputs, lizer application or agroforestry practices and to climate resilience (section 3.3.1). to increase soil organic matter (Maranguit, crop diversification There is evidence (although only from Guillaume and Kuzyakov, 2017). In Xish- small-scale studies) for long term declines uangbanna, China, soils became degraded goals—objectives in soil fertility with repeated cultivation of in structure, moisture, nutrient and severe that could be rubber monocultures. For example, in Hain- erosion 30 years after conversion from for- an Island, China, soil fertility was measured est to monoculture (Chen et al., 2019). Sim- achieved using in rubber monocultures from soil samples ilarly, the ability of rubber trees to deplete agroforestry taken in 1954, 1982, 1990 and 1995. These groundwater resources has been shown at showed that soil organic matter decreased the local scale in the Xishuangbanna (re- methods.” by 48%, total nitrogen by 54%, available po- viewed by (Ma et al., 2019)). Here, the au- tassium by 57%, and available phosphorus by thors suggest that, in order to provide dry 64%, despite fertilizer application (Cheng, season water resources, rubber manage- Wang and Jiang, 2007). Soil nutrient re- ment should aim to maximise rainwater serves become depleted in monocultures penetration whilst meeting biodiversity due to soil erosion, mineralisation (decom- conservation and crop diversification goals position) of soil organic matter (SOM) and – objectives that could be achieved using

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agroforestry methods (Ma et al., 2019). culture and forest in Indonesia found that 5-7 replicate plots were ideally needed to detect This section summarizes evidence for soil land-use change effects on soil nutrient pa- health and water management outcomes of rameters (Allen et al., 2016). Seasonal vari- agroforestry practices in rubber, relative to ability, soil types, fertilizer application also all monoculture practices. Our review found a affect soil metrics. Hence, it is important to substantial number of studies showing the keep these methodological considerations in benefits of permanent intercropping (es- mind and to understand that not all studies pecially cover crops and understory plants) in this section may fulfil these considerations. and jungle rubber agroforestry for various indicators of soil health and water infiltra- tion, and little evidence of nutrient competi- 3.3.3.1 AGROFORESTRY tion between rubber trees and intercrops. METHODS (PERMANENT Terracing and reducing herbicide application INTERCROPPING; JUNGLE to once per year (thus allowing more weeds RUBBER) to cover the soil) were also beneficial for soil health, and can be complementary to agro- Intercropping rubber with perennials, an- forestry practices. While we have not close- nuals, and cover crops in young and mature ly scrutinised the statistical methods used in rubber plantations can improve soil quality each study presented here, we caution that by various interlinked mechanisms. Inter- changes in soils in relation to land use change crops contribute to soil quality by physically must be replicated across multiple study sheltering the soil from erosion and nutrient plots to take into account spatial variability. leaching, by producing root exudates and For example, a study of jungle rubber, mono- contributing leaf litter to the soil, or via ben- eficial fungi associated with roots of cover crops (especially leguminous species). Inter- Soil erosion in rubber terrace crop plants also affect soil pH or soil acidity, system in Thailand which in turn is related to soil microbial activ- Credit: CC BY-NC 4.0 EWT

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ity, and also impacts carbon (C) and nitrogen study on steep slopes in Northern Thailand (N) cycling. found that rubber tree leaf litter was not ef- “The presence of understory fective in reducing water and soil runoff at plants further reduces surface Cover cropping has received much research the end of the rainy season when the leaves runoff and soil erosion, such attention. There is strong evidence of posi- have partially decomposed (Neyret et al., tive benefits for cover cropping in rubber 2020). The presence of understory plants as tea and maize in young plantations from older literature, including further reduces surface runoff and soil rubber plantations.” “a long-lasting rubber yield increase” based erosion, such as tea (Liu et al., 2017) and on long-term trials ((Broughton, 1977) as maize in young rubber plantations (Neyret reviewed in Langenberger et al. (2017)). The et al., 2020). The Northern Thailand study long-term benefits are particularly true for le- also show that increasing ground cover with Chen, Liu, et al., 2019) or legume cover crop- guminous cover crops on poor soils, but natu- low-growing plants (unspecified, but could ping with Flemingia macrophylla (Wu, Liu and ral regrowth of ground-covering plants on fer- be spontaneously occurring plants, or cover Chen, 2016a), but leaf nutrient content was tile soils and recently cleared forest soils also crops) to ~31% cover would decrease runoff higher with the legume cover crop Pueraria provide similar benefits ((Broughton, 1977; by a third (Neyret et al., 2020). phaseoloides (Clermont-Dauphin et al., 2018). Blencowe, 1989) as reviewed by Langenberg- er et al. (2017). Multiple recent studies from A common concern of farmers is that inter- This substantial body of evidence – also sum- China show the soil benefits of cover crop- crops or the presence of other plants may marized in Table 3 - clearly shows the bene- ping with Flemingia macrophylla, a popu- compete with rubber for soil nutrients and fits of permanent intercropping (and jungle larly grown leguminous shrub with medicinal water (but see evidence for facilitative water rubber agroforestry) for enhanced soil carbon properties, compared to rubber monoculture uptake in the presence of intercrops in section (important for nutrient retention, water hold- alone (Table 3). 3.3.1.1). A few studies asked whether below- ing capacity and climate change mitigation), ground competition between intercrops and soil nutrients (nitrogen, phosphorus, potas- In monocultures, rubber leaf litter cover- rubber would affect uptake of nutrients by sium, calcium and magnesium, iron, sulphur ing >70% of the soil surface helped reduce looking at leaf nutrient content. There were and manganese), reduced erosion, improved surface runoff and soil erosion on slopes in no obvious effects on leaf nutrients in sharp- soil structure, reduced soil acidity and en- southern China (Liu et al., 2017); however, a leaf galangal intercrop systems (Wu, Zeng, hanced soil microbial biodiversity.

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BOX 7 THE COMPLEXITIES OF SOIL AND WATER MECHANISMS IN AGROFORESTRY SYSTEMS

A study from China compared soil nutrient than natural forest, while simpler intercrop the soil profile, leading to drier deep soil layers concentrations, water content and soil water systems showed esoteric responses. However, in jungle rubber (and natural forest) relative to residence time between rubber monoculture effects on soil water content, residence time monoculture and simple agroforests. and four agroforestry systems: two single inter- and some soil nutrients (P, K, Ca) were nega- crop (orange, tea), a double intercrop (orange tive with increasing complexity, thought to be The authors conclude that intercropping in and tea), and a ‘jungle’ system formed from caused by below-ground competition between rubber plantations is effective at increasing soil abandonment of an orange/tea system that plant species. Soil water content was lower in organic matter (and thus carbon and nitrogen), was allowed to develop natural vegetation, and jungle rubber than in the other agroforestry and in turn increase soil moisture content. Soil contained 11 non-rubber species of tree, shrub systems, or in forest. This was considered to water and nutrients were reduced in the more and herb (Wu et al., 2020). This study offers be due to water competition from the herba- complex systems (forest and jungle rubber) nuanced insights into how natural regrowth ceous plant layer in the jungle rubber system. due to increased competition between plant may affect intercropping systems, and how Increased soil carbon generally improves the species (particularly from herbaceous plants), ‘jungle’ rubber weighs up to simple intercrop- water-holding capacity of soils, due to changes and due to increased drainage and aeration ping systems. in soil structure, so there were positive correla- of the soil (which may in turn lead to nutri- tions between soil carbon, nitrogen and water ent leaching). However, as rubber trees are Soil carbon and nitrogen were lowest in content. However, the presence of herbaceous deep-rooted, soil moisture at deeper levels monoculture, highest in natural forest, and plant complexity alongside shrubs and trees may be unaffected. The authors suggest increased relative to monoculture in all four in the jungle system may improve drainage avoiding dense planting of herbaceous species agroforestry systems (no strong differences to such an extent that soil water content was between rubber trees to avoid negative im- between the systems). Soil nutrients (P, K, Ca, reduced, combined with the effects of ad- pacts on soil moisture and nutrients (P, K, Ca). Mag) varied among the agroforestry systems, ditional plant transpiration which could be However, the study did not control for applica- with no effects for some nutrients in some offsetting any benefits of soil shading by leaves tion of fertilizers in the simpler systems, which systems relative to monoculture, but in most on soil moisture. Competition between com- would be expected to affect soil nutrients (Wu cases, jungle rubber had reduced nutrients plex vegetation and rubber trees may cause et al., 2020). relative to all other rubber systems, and less rubber trees to take up water from deeper in

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TABLE 3 EFFECT OF DIFFERENT RUBBER INTERCROPPING SYSTEMS ON SOIL HEALTH, AS COMPARED TO MONOCULTURE RUBBER

EFFECT OF AGROFORESTRY SYSTEM/PRACTICE SYSTEM LOCATION SOURCE

SOIL CARBON (C = CARBON, SOC = SOIL ORGANIC CARBON)

Lower SOC, labile C, recalcitrant C but higher dissolved organic carbon Intercrop: Cardamom China (Wang et al., 2020)

Higher SOC, reduced C loss, better C accumulation rates Intercrop: Cocoa/ Coffee/Rosewood China (Chen et al., 2017) Cover crop: Flemingia macrophylla

Higher SOC in topsoil (0-10cm) Intercrop: Coffee/Tea China (Li et al., 2020)

Higher soil C Intercrop: Orange/Tea/ Orange+Tea China (Wu et al., 2020)

Higher soil C (no significant difference to managed intercrops) “Jungle rubber”- abandoned Orange+Tea China (Wu et al., 2020)

No significant difference in soil C Intercrop: India (Jessy, Joseph and Coffee/ vanilla/ Garcinia / nutmeg George, 2017)

SOC greater in the double and triple plantain-row systems at one of the two Intercrop (temporary): Plantain Ghana (Tetteh et al., 2019) study sites

Higher soil labile organic carbon and nitrogen Cover crop: China (C.-A. Liu et al., 2018) Flemingia macrophylla

41% versus 62% loss of SOC in the topsoil (0-30cm) relative to natural Jungle rubber Sumatra, Indonesia (Guillaume, Damris and forest; likely only lost by mineralisation to CO2 and not by erosion Kuzyakov, 2015)

Higher annual carbon return to the soil (3.7 Mg C ha-1 vs only 1.9 Mg C ha yr Jungle rubber Sumatra, Indonesia (Kotowska et al., 2016). in monoculture)

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EFFECT OF AGROFORESTRY SYSTEM/PRACTICE SYSTEM LOCATION SOURCE

SOIL NUTRIENTS (N = NITROGEN, P = PHOSPHOROUS, K = KALIUM, CA = CALCIUM, MG = MAGNESIUM, FE = FERRUM, MN = MANGANESE)

Higher N (total organic, labile and recalcitrant N) Intercrop: Cardamom China (Wang et al., 2020)

Higher soil organic N, reduced N loss, better N accumulation rates Intercrop: Cocoa/Coffee/Rosewood China (Chen et al., 2017) Cover crop: Flemingia macrophylla

Higher total N stock in topsoil (0-10cm) Intercrop: Coffee/Tea China (Li et al., 2020)

Higher N at all depths Intercrop: Cocoa Brazil (Oliveira et al., 2019)

Higher P concentrations in all fractions Intercrop: Cocoa/acai palm/cupuassu fruit Brazil (Viana et al., 2018)

Higher soil N; variable results for soil P, K, Ca, Mg (fertilizer application not Intercrop: Orange/Tea/Orange+Tea China (Wu et al., 2020) accounted for)

Higher soil N; soil P, K, Ca, Mg generally lower than managed intercrops “Jungle rubber”– abandoned Orange+Tea China (Wu et al., 2020)

No significant difference in P, K, Ca, Mg; but higher in some cases 10 years Intercrop: India (Jessy, Joseph and after rubber planting. Coffee/vanilla/Garcinia/nutmeg George, 2017)

No difference (despite monoculture being fertilized annually, and rubber- Intercrop: Bamboo Thailand (Andriyana et al., 2020) bamboo not)

SON greater in the double and triple plantain-row systems at one of the two Intercrop (temporary): Plantain Ghana (Tetteh et al., 2019) study sites (note NPK fertilizer was applied to each plantain plant)

Higher soil labile organic nitrogen Cover crop: Flemingia macrophylla China (C.-A. Liu et al., 2018)

P fractions varied depending on the type and soil depth and stand age. Total Cover crop: Flemingia macrophylla China (C. -A. Liu et al., 2018) P stock, to a certain extent, was reduced in young intercrop (10 years), but increased in mature intercrop (22 years)

Higher or no difference in soil nitrogen – effect was site dependent Jungle rubber Sumatra, Indonesia (Guillaume, Damris and Kuzyakov, 2015)

Higher annual return rates for soil S, N, P, K, Fe, Mg, Mn Jungle rubber Sumatra, Indonesia (Kotowska et al., 2016).

Conversion of jungle rubber to monoculture led to overall reduction of P Jungle rubber Sumatra, Indonesia (Maranguit, Guillaume stocks due to a strong decrease of soil organic matter; fertilization did not and Kuzyakov, 2017). compensate for the P losses in long term in monoculture.

84 RUBBER AGROFORESTRY Environmental Outcomes EFFECT OF AGROFORESTRY SYSTEM/PRACTICE SYSTEM LOCATION SOURCE

SOIL EROSION

Better soil physical properties and nutrients Intercrop: Cocoa China (Chen et al., 2019) Cover crop: Flemingia macrophylla

Improved soil aggregation, reduced soil erosion Intercrop: Cocoa/ Coffee/Rosewood China (Chen et al., 2017) Cover crop: Flemingia macrophylla

Better infiltration of rainfall into soil, reduced surface runoff and soil erosion Intercrop: Clerodendranthus spicatus / China (Jiang et al., 2017) Amomum villosum (medicinal plants)

Reduced surface runoff and soil erosion Intercrop: Tea China (Liu et al., 2017)

Greater rainfall interception; no difference in soil bulk density Intercrop: Bamboo Thailand (Andriyana et al., 2020)

Increased water infiltration (higher in triple row vs double or single row) Intercrop (temporary): Plantain Ghana (Tetteh et al., 2019)

Reduced surface runoff and soil erosion Intercrop (temporary): Maize Thailand (Neyret et al., 2020)

Less soil eroded (over 15 years) from the upper soil layer (measured at one Jungle rubber Sumatra, Indonesia (Guillaume, Damris and site). Subsoils were not affected. Kuzyakov, 2015)

SOIL PH (ACIDITY)

Less acidic soil Intercrop: Cocoa/coffee China (Li et al., 2020)

Mitigated soil acidification and nutrient depletion Cover crop: Flemingia macrophylla China (C.-A. Liu et al., 2019);

No significant difference in soil acidity Intercrop: Coffee/vanilla/Garcinia/nutmeg India (Jessy, Joseph and George, 2017)

SOIL MICROBES

Higher soil bacterial biodiversity Cover crop: Flemingia macrophylla China (C.-A. Liu et al., 2019)

Significantly higher soil microbial population, no difference in fungi or Intercrop: Coffee/vanilla/Garcinia/nutmeg India (Jessy, Joseph and Actinomycetes George, 2017)

Increased microbial mass (higher in triple row vs double or single row) Intercrop (temporary): Plaintain Ghana (Tetteh et al., 2019)

Higher species richness, abundance and biomass of testate amoebae (soil Jungle rubber Sumatra, Indonesia (Krashevska et al., 2016). and leaf litter microbes), including reduced density of species with siliceous (silicon-containing) shells 85 RUBBER AGROFORESTRY Environmental Outcomes

3.3.3.2 NON-AGROFORESTRY A computer model simulating weed growth 3.3.3.3 RUBBER AS A TOOL METHODS (TERRACING, WEED impacts on soil erosion in rubber monocul- FOR RESTORATION OF MANAGEMENT) tures over 20 years indicates that minimis- DEGRADED LAND ing herbicide application to once per year, Terracing helped reduce soil organic car- or no weeding at all, could substantially An agroforestry system comprising 30 native bon loss from converting secondary for- reduce soil loss relative to more regular tree species (used for timber, food or medici- est to rubber monoculture in mountain- weeding (twice per year). A no-weeding ap- nal purposes), intercropped with rubber, wild ous sourthern Yunnan province, China (De proach would result in dense undergrowth crape myrtle (Malphigia glabra) and Axiote Blécourt et al., 2014). The study found that that is unacceptable to local farmers due to (Bixa orellana), was established in Brazil as terracing enhanced soil organic carbon re- their concerns of poisonous caterpillars and part of a land restoration scheme following covery (down to 1.2 m depth) as compared inconvenience for tapping; hence, the authors major soil erosion problems. The agroforest- to non-terraced areas in rubber plantations. recommended limiting weeding to once a ry system showed accumulation of soil organ- year (H. Liu et al., 2019). ic carbon over five years in all plots, but was slowest in plots that included soil ploughing as part of management (Siqueira et al., 2020).

3.3.4 ECOSYSTEM RESILIENCE AND BIODIVERSITY Do rubber agroforestry systems enhance biodiversity in the Brazilian Amazon was dependent on subsidies, and when subsidies were available and ecosystem resilience compared with monocultures? (re-introduced in 2012 and current status unknown) they also supported the planting A global extinction crisis is underway, and 3.3.4.1 WILD RUBBER AND of rubber agroforests along riverbanks (sep- providing space for nature within cultivated AGROFORESTS IN BRAZIL arate from natural rubber tapping from wild lands is critical for conservation of biodiver- Wild tapped rubber from trees growing nat- trees), adjoining natural forest. These agro- sity in all its forms. This section summarizes urally in the Amazon is unique in that it is forests additionally provided wildlife habitat, the role agroforestry practices and systems sourced from a natural rainforest ecosystem, shown by the use of the agroforests as hunt- can play in supporting ecosystem resilience which will therefore support rainforest bio- ing grounds (Schroth et al 2003, in (Schroth and biodiversity, relative to monoculture diversity (WWF-UK, 2014). Rubber tapping and Da Mota, 2013)). practices.

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In a plantation context in Brazil, the number 3.3.4.2 JUNGLE RUBBER of fruit feeding butterfly species was greater in As the most structurally diverse agroforest- unmanaged rubber plantations that contained ry system in Southeast Asia, jungle rubber substantial plant regrowth between the rubber systems in Indonesia have received research rows, than in highly managed rubber planta- attention for their biodiversity benefits. Jun- tions, and may act as stepping stones for for- gle rubber systems contain multiple tree est-dependent species to move through the species (native, wild-grown or introduced/ landscape (Cambui et al., 2017). Rubber planta- planted) and are minimally managed, mean- tions containing additional trees (eg cacao, ba- ing multiple species of plant naturally regen- nana, jackfruit and guava), as well as support- erate beneath the tree canopy. This complex ing epiphytic bromeliads (specialised plants physical structure, together with a diversi- that grow on the surface of trees), were also ty of plant species, is expected to support used by endangered golden lion-headed tama- much more biodiversity than a monoculture rins and Wied’s marmosets, as part of their plantation. A review of studies prior to 2015 home range; there was no evidence that they showed that natural forest conversion to used monoculture rubber in the same way. rubber monoculture inevitably results in These species eat fruit, and insects (found in biodiversity loss (reduced numbers of bird, bromeliads) (De Vleeschouwer and Oliveira, bat, plant and insect species), but that jun- 2017). Rubber agroforestry therefore provides gle rubber agroforests can support some benefits for biodiversity whether in planta- forest-dependent species that are never tion-dominated landscapes, or in landscapes found in monocultures of rubber or oil still containing tracts of rainforest. palm, representing critical forest-like habitats in places where forest is rapidly being lost (Warren-Thomas, Dolman and Great Hornbill (Buceros bicornis) in Thailand. Edwards, 2015). Subsequent studies in Su- matra have reiterated these findings. Credit: CC BY-NC 4.0 TCW

Flying lizard (Draco spp.) in Thailand Data from several studies was brought to- rubber system gether to show that for birds, and trees, Credit: CC BY-NC 4.0 EWT

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species richness in jungle rubber was higher are important for conserving epiphyte diver- than in rubber monocultures, and for birds sity, especially of ferns and orchids (Böhnert and ferns, species diversity in jungle rubber et al., 2016). was quite similar to natural forest, including some forest-dependent species (Beukema et In a study of all plants in just eight plots found al., 2007). Jungle rubber type agroforestry in that jungle rubber contained 652 plant spe- Central Kalimantan also supports a diversity cies, while rubber monocultures contained of rattan (vine) and tree species (Rotinsulu et only 230 plant species (natural forest con- al., 2013; Tata, 2019). tained 963) (Rembold et al., 2017). The genet- ic and phylogenetic diversity of plants found A more recent comparison of the epiphyt- in jungle rubber agroforests were also much ic plants (those that grow on another plant greater than in rubber monocultures, because e.g. ferns, bromeliads, air plants, orchids) in jungle rubber contains species with different jungle rubber compared to monocultures in life history traits, and species that are more Sumatra, Indonesia, found that jungle rubber distantly related to each other (therefore cap- had similar species diversity to natural rain- turing a wider range of functional features) forest, which was much higher than rubber (Breidenbach et al., 2018; Kusuma et al., 2018). monocultures. The authors conclude that Finally, the number of invasive plant species, jungle rubber is a refuge for epiphytes and which can dominate agricultural systems and cause problems for farmers and local biodi- versity, was lower in jungle rubber than in Butterfly (Hypolimnas bolina) in monoculture (Wahyuni et al., 2016). rubber agroforestry, Thailand; Trimeresurus spp. pit viper in A study that combined extensive sampling of Thailand rubber tropical biodiversity (almost 27,000 species, Credit: CC BY-NC 4.0 EWT including high diversity and high biomass Young pangolin (Manis javanica), groups spanning all trophic levels, i.e. from captured in rubber plantation in birds to bacteria, above and below ground) Myanmar by local farmers Credit: CC BY-NC 4.0 TCW

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found that strong biodiversity losses from al- ly eat cultivated fruits grown in rubber agro- relative to monoculture practices. most all groups occurred when natural forest forests in northern Sumatra (i.e. crop-raiding, and jungle rubber agroforests were convert- eating fruits grown for human consumption), Rubber agroforests containing permanent ed to monocultures (whether of rubber or oil but were unable to forage in neighbouring oil intercrops of fruit, palms, timber or vegeta- palm); exceptions were e.g. bacteria, although palm plantations. The authors conclude that bles contained more species of fruit-feeding even within these groups, the diversity of spe- retention of rubber agroforests containing butterflies than monocultures, and different cies found in natural forest (rather than all fruiting trees, and preventing their conversion butterfly species, but had similar numbers of possible species) declines (Grass et al., 2020). to oil palm monocultures (an ongoing pattern reptile and bird species. Bird species richness The only exception to these patterns are soil in the region) is critical for orangutan conser- was greater in rubber plots that had more macroinvertebrates: the total number of spi- vation in that landscape (Campbell-Smith et understory vegetation, whether or not they der species, and their functional diversity (the al., 2011). Managing conflicts between farm- contained agroforestry crops. Conservation types of functions they provide in the ecosys- ers growing fruit crops for consumption or priority and forest-dependent birds were not tem), was similar between jungle rubber and sale, and protection for orangutans, is likely supported within monoculture rubber (War- monoculture, although the number of forest to be a complex problem in this case. ren-Thomas et al., 2020). In contrast, in North species was much lower in rubber monocul- Sumatra, bird surveys found that intercropped tures than jungle rubber, and the types of spe- rubber systems containing tree species such as cies differed between the two systems (Pota- (Durio zybethinus), candle nuts (Aleur- PERMANENT pov et al., 2020). Similarly, centipede species 3.3.4.3 ites mollucana), duku (Lansium domesticum), INTERCROPPING number, abundance and biomass did not dif- jengkol (Pithecellobium lobatum), mangosteen fer between jungle rubber and rubber mono- The evidence for biodiversity benefits from (Garcinia mangostana) and cacao (Theobroma culture (Klarner et al., 2017), and species rich- permanent intercropping in rubber is scarc- cacao) contained 46 bird species (including ness, density and functional group richness of er, not least because these systems are less one species of conservation concern), com- leaf litter macro-invertebrates did not differ common in the landscape. Permanently in- pared to 30 in rubber monocultures, and 122 between jungle rubber and monoculture rub- tercropped systems will be much less struc- in nearby forest (Ayat and Tata, 2015). ber (Mumme et al., 2015) turally complex than jungle rubber, contain- ing fewer layers of vegetation below the tree In Hainan, China, leaf-litter ants, including Finally, jungle rubber systems can also sup- canopy, and will contain fewer plant species. invasive species (that can disrupt native bio- port orangutans, which were found to routine- However, there is evidence for some benefits diversity and cause ecosystem disruption),

89 RUBBER AGROFORESTRY Environmental Outcomes

were compared between rubber agroforests and many species are generalists that can live biodiversity. If agroforests replace forests, containing understory crops and rubber in a range of different habitats, are not spe- this will result in declines for biodiversity monocultures. Agroforests contained simi- cies of conservation concern, and are not for- and ecosystem resilience, as well as car- lar numbers of ant species, but crucially they est-dependent species. bon emissions (see section 3.3.2 on carbon). contained fewer invasive ant species than However, diversified agricultural systems monocultures (thus agroforests were better 3.3.4.4 NON-AGROFORESTRY on the farm and landscape scale support for native biodiversity). The study showed METHODS (WEED MAN- biodiversity and an array of ecosystem that invasive ant species were associated with AGEMENT) services (Tamburini et al., 2020). Multiple simpler undergrowth structure in mono- There is some evidence from Thailand that studies report increased diversity of plants cultures, so the addition of secondary plant the presence of understory vegetation i.e. and birds in jungle rubber compared to other species in the agroforest, which increases the “weeds” or “undergrowth” increases bird systems, and the conservation of these for- vegetation structure, reduced the presence of species richness slightly compared to rub- est-like systems in lowland landscapes that invasive ants (Lee, Wang and Guenard, 2020). ber monocultures (Warren-Thomas et al., contain few forest fragments may be critical 2020). Similarly, (Aratrakorn, Thunhikorn to the persistence of forest-dependent spe- Finally, in the Philippines, (Agduma et al., and Donald, 2006) found that rubber and oil cies in these landscapes, including orangu- 2011) reported 110 plant species growing palm plantations supported lower bird diver- tans. Meanwhile, simple intercropping sys- alongside rubber in an agroforestry system sity (41 species each) than nearby forest (108 tems (i.e. simple agroforests consisting of within a plantation, including trees, shrubs, species), with different species of birds living just two or three crops) do not necessarily vines, herbs, grasses and ferns. These include in each system (species in plantations were benefit birds, but can benefit butterflies, ants eight threatened plant species, including dip- mostly widespread generalists, but that the and plant species. Crucially, there is also ev- terocarp trees, endemic trees and figs that are presence of dense and extensive understory idence that diversified systems can increase keystone species for ecosystems. (Achondo vegetation growing between the rubber trees the hospitability of the landscape for species et al., 2011) found in a short bird survey that increased bird diversity from eight species moving between patches of remaining forest rubber agroforests (containing fruit trees and per survey, to 10 species. habitat, meaning agroforestry may increase native tree species (Agduma et al., 2011)) in habitat connectivity for species, relative to Mindanao contained 23 bird species (same as 3.3.4.5 CONNECTIVITY AND monocultures (Haggar et al., 2019). This will nearby oil palm plantations) including eight BIODIVERSITY BENEFITS be critical not only for long-term species per- endemic bird species (restricted to the Phil- sistence, but also to allow species respond to ippines), but this is low number compared to Agroforestry of any kind cannot replace climate change and move through landscapes bird diversity in natural systems in the area, the role of forest ecosystems in supporting to track changes in their environment.

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4 Discussion

The evidence outlined above shows government policies, or through that agroforestry systems can provide constraints of contract farming. multiple benefits for livelihoods and food security and nutrition, improve In the following sections, barriers soil quality, available nutrients and and problems associated with adopt- water use, reduce soil erosion, en- ing rubber agroforestry are explored, hance biodiversity, and offer options and recommendations for scaling-up for climate resilience. It is clear that of rubber agroforestry are made. This agroforestry systems can fail to pro- section contains information from vide benefits relative to monocultures interviews, supplemented with evi- if they are inappropriately designed, dence from the literature, and uses if they do not match local constraints case studies to examine complexities on land and labor, or if markets for and feedbacks among barriers. This secondary products are weak. It is also section will largely focus on rub- clear that farmers in multiple con- ber-based (permanent) intercropping texts independently choose agro- systems, as this system has the most forestry practices, sometimes in the potential for scaling up among small- face of direct disincentives from holders and industrial plantations.

Rubber agroforestry to secure resources for future generations Credit: CC BY-NC 4.0 TCW

91 RUBBER AGROFORESTRY Discussion

4.1 BARRIERS TO ADOPTION OF RUBBER AGROFORESTRY

4.1.1 GOVERNMENT POLICIES, LAND TENURE, AND CONTRACTS

Government policies have been cited as a ber-based agroforestry is more widespread ing Thailand’s rubber production (Stroesser major factor influencing adoption of rub- (Rodrigo, Stirling, Naranpanawa, et al., 2001; et al., 2018). The remaining practitioners of ber agroforestry practices (Viswanathan and Omokhafe et al., 2014; Sen, 2015; Sankalpa, agroforestry in Thailand are therefore rare, Bhowmik, 2016; Stroesser et al., 2018).55 Mon- Wijesuriya and Ishani, 2020).56 despite the lifting of a ban on multi-crop- oculture was promoted as an agricultural ping by ORRAF in 1992 and policy to promote model in countries like Malaysia, Thailand, In the context of Thailand, the world’s big- agroforestry and non-rubber tree crops in Laos, Cambodia, China and the Ivory Coast, gest rubber producer, government initiatives 2014 (Delarue and Chambon, 2012). Financial so policies tended to favour rubber monocul- to improve rubber production played a key support or subsidies without technical rec- tures, and technical recommendations from role: low-yielding complex “jungle rubber” ommendations for setting up rubber agrofor- state institutions were focused on monocul- agroforestry systems, comprising a wide di- estry plots may not be sufficient to convince ture systems. This resulted in a lack of aware- versity of fruit and timber trees, were widely farmers accustomed to monoculture system ness by smallholders about agroforestry. grown until a clonal rubber replanting pro- to adopt agroforestry.57 It should be noted In other countries with a cultural history of gram by the Office of Rubber Replanting Aid that modern intercropping systems may re- agroforestry, which have not had such strong Fund (ORRAF) strongly incentivized mon- quire different knowledge to that used to governmental incentives for monocultures, oculture planting in the 1960s, effectively maintain traditional jungle rubber systems. such as Sri Lanka, Vietnam and Nigeria, rub- banning agroforestry, while hugely increas-

55 Interviews, Rhett Harrison, Eric Penot, Michael B. Commons, and anonymous. 56 Interview, Kenneth Omokhafe. 57 Email consultation, Bénédicte Chambon.

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Lack of land or tree tenure security was hardwoods even if those trees were planted “Smallholders are more also cited as a barrier to adoption of rub- on their own land.60 Once this prohibition ber agroforestry.58 Smallholders are more was lifted, hardwood tree planting greatly likely to invest in longer-term likely to invest in longer-term agroforestry increased and many more farmers grew and agroforestry systems when they systems when they have more secure tenure sold hardwood seedlings.61 A lack of land ti- and land-use rights on their farms, and to tles in Cambodia also makes it difficult for have more secure tenure and plant trees when they have sufficient length smallholders to access finance (e.g. loans) land-use rights on their farms, of tenure and full rights on the trees they to invest in rubber farms (Andriesse, 2014). plant (FAO and ICRAF, 2019). In addition, In Liberia, land tenure was the main imped- and to plant trees when they the classification of rubber trees by gov- iment to adopting agroforestry or tree-crop- have sufficient length of tenure.” ernment agencies (as an agricultural crop ping, as well as perceptions around compe- vs timber crop vs forest cover) can also af- tition between tree crops and herbaceous fect smallholder decisions, in response to crops (Fouladbash and Currie, 2015). (see detailed case study Box 2 in section 3.1). land-zoning decisions and policies from the Contractual obligations can also change land government (e.g. encouraging agricultural Contracts for smallholders provided by rub- tenure – deliberately, when smallholders de- intensification or forest restoration on cer- ber companies guide production methods and cide to provide labor instead of land for rub- tain lands). Interlinked with that, policies the ability to implement agroforestry practic- ber companies or involuntarily, when farmers around timber trees also discouraged the es. A comparison of smallholder farmer liveli- are illiterate and do not understand the con- establishment of rubber-timber intercrop- hoods growing rubber in Cambodia and Laos tractual conditions (for more details see sec- ping systems. For example, prior to 2019, showed that rubber companies contracting tion 3.2.2). The lack of support for smallhold- the Rubber Authority of Thailand (former- farmers advise smallholders in Laos not to er associations, networks and co-operatives ly ORRAF, as above) restricted the number intercrop, in order to maximise rubber yields (which would facilitate community organiz- and type of species of timber on farms59 and (Andriesse, 2014). This is despite smallhold- ing and collective action) likely further limit smallholders required permits to cut native er interest in adopting agroforestry practices smallholders’ options and negotiating power.

58 Interviews, Rhett Harrison (land tenure and China example). Email consultation, Eric Penot (unfavourable tree tenure in Vietnam and Cote d’Ivoire). 59 Interview, Sara Bumrungsri. 60 Interviews, Sara Bumrungsri and Michael B. Commons. 61 Interview, Michael B. Commons.

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4.1.2 MARKETS, LABOR CONSTRAINTS AND RISK Low rubber prices may encourage small- ed a lack of local supportive policies, and on other more profitable economic activities. holders to switch to intercropping so they the demand side, hesitancy from companies In the case of jungle rubber, it is less labor can derive income or subsistence from to adopt the eco-certification concept due to intensive than rubber monoculture but pro- intercrops.62 Low prices may also lead to concerns about distorting market prices (Lei- vides lower returns (if high yielding clones the temporary abandonment of rubber and mona and Joshi, 2010). are not used), so often the specific decision renewal of tapping once prices recover, or depends on the financial and labor resources to the conversion of rubber to other planta- Labor shortages were a commonly cited bar- available to the smallholder farmer. Agrofor- tion crops, such as banana in Xishuangbanna rier, as this was a crucial aspect for practicing estry strategies with less labor requirements post-2011.63 Although jungle rubber agrofor- most forms of agroforestry.64 In general, there (e.g. allowing natural regeneration in rubber estry can provide environmental benefits, is a decline in the rural farming labor force plantations) can be suitable in locations with this does not translate to any significant in- due to economic development and urban mi- labor scarcity. centives for smallholder farmers in Indone- gration. The demands on a smallholder’s sia (Leimona and Joshi, 2010). Smallholder time – especially from other more profita- Lack of access to markets for intercrops farmers showed a willingness to participate ble sources of income or off-farm livelihood were also cited as a barrier to agroforestry.66 in a certification program, but expected a activities – may mean that they do not have A review of agroforestry in Vietnam also high- 100% price increase in natural rubber (note the time to set up or maintain agroforestry lighted further market constraints, such as that the study was written in 2010, before the plots.65 These same factors apply to wild rub- the difficulty of scaling for market (the diver- 2011 price spike and subsequent slump; pric- ber extraction in the Amazon. As rubber tap- sity and small volume of products from small es today are roughly similar to 2005-2006). ping provides low returns for how physically scale agroforestry, which exceeds household Barriers to eco-certification adoption includ- and time demanding it is, locals will prefer consumption but insufficient for commercial

62 Interview, Rhett Harrison. 63 Interview, Rhett Harrison. 64 Interviews, G. Langenberger, R. Harrison, S. Bumrungsri. Email consultation, B. Chambon. 65 Interview, Uraiwan Tongkaemkaew. 66 Email consultations, Gerhard Langenberger and Julia Quaedvlieg.

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purposes), limited or unstable markets (agro- and stick to existing systems that have been including a fear of increased snakes, mosqui- forestry products not matching commercial “trialled and tested”. 67 This is, because there toes, and ghosts.70 Conversely, in areas where requirements) (Sen, 2015). is a risk that either rubber, or the associated rubber agroforestry is a common practice, crop, or even both will not do well.68 There is risk aversion may mean that farmers would As the rubber agroforestry model is still rare also a perception that intercrops will com- prefer to retain some agroforest area instead in most countries, and farming is already pete with rubber and reduce rubber produc- of fully converting to monocultures (e.g. a subject to multiple threats (e.g. weather and tivity, among both smallholders and rubber model based study in Indonesia found that market volatility), smallholders and indus- companies69 (Haberecht, 2010). Researchers risk-averse farmers chose to retain a greater trial plantations accustomed to the mono- based in Thailand also mentioned the social area of jungle rubber (Djanibekov and Villa- culture model are likely to be risk averse stigma related to having an “untidy” farm, mor, 2017).

4.1.3 FINANCE, CAPITAL AND KNOWLEDGE

Some interviewees suggest that adoption of then they do not see a need to practice agro- of best practices and problems, their interac- rubber agroforestry is largely driven by eco- forestry, which would require an increase tions with the rubber trees and each other, as nomics and practical constraints. If small- in management complexity, including ad- well as knowledge of how to design the agro- holders receive sufficient income from rub- ditional knowledge/expertise and labor forestry plot. Industrial plantations will need ber monoculture or alternative sources of in- needs.71 Every additional crop or livestock to develop whole new systems to manage the come, especially when rubber prices are high, species added to the plot requires knowledge different components and outputs of agro-

67 Interviews/email consultation, Bénédicte Chambon, Sara Bumrungsri, Uraiwan Tongkaemkaew, Michael B. Commons, Linda Preil. 68 Email consultation, Bénédicte Chambon. 69 Interviews, Rhett Harrison, Uraiwan Tongkaemkaew, anonymous. 70 Interviews, Sara Bumrungsri, Uraiwan Tongkaemkaew. 71 Interviews, Gerhard Langenberger, Rhett Harrison, Sara Bumrungsri, Uraiwan Tongkaemkaew, Michael B. Commons.

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forestry. In Thailand, there is a decreasing practised shifting cultivation (see Box 2 in Some types trend in family labor availability, as young- section 3.1). In addition, some types of agro- of agroforestry er family members have access to improved forestry require financial investments with education and employment prospects in ur- delayed returns, such as intercropping with require financial ban areas; rubber tappers are increasingly timber, whereas smallholders may prefer to hired to help run rubber smallholdings, and invest in shorter term revenue options. 73 investments with landowners have reduced capacity for plot delayed returns, such management activities which may reduce In Sri Lanka, lack of technical knowledge their interest in increasing management was a constraint for farmers to adopt rub- as intercropping complexity with additional crops, although ber intercropping (Iqbal, Ireland & Rodrigo, new benefit-sharing agreements with rubber 2006) in (Hondrade et al., 2017) and (Rodri- with timber, whereas tappers to include intercrops (for example, go, Stirling, Naranpanawa, et al., 2001). Se- smallholders may in the non-tapping season) may be an op- curity, or theft of intercrops was also per- tion.72 In other locations, such as Laos, agro- ceived to be a problem for smallholders in prefer to invest in forestry practices have been independently Sri Lanka (Rodrigo, Stirling, Naranpanawa, shorter term revenue established by farmers who, until recently, et al., 2001), and Thailand.74

options.” 72 Interview, Michael B. Commons. 73 Interview, Rhett Harrison. 74 Interview, U. Tongkaemkew

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BOX 8 AGROFORESTRY ADOPTION AND EFFECT OF POLICY REFORMS IN XISHUANGBANNA, CHINA

The adoption of rubber intercropping in Xish- (labor constraint), as were farmers with more smallholders to adapt livelihood strategies uangbanna, China, was influenced byethnici - mature rubber area (also labor constraints, as when rubber prices fluctuate (Xu, 2006). When ty, household wealth, labor capacity, the tapping is labor intensive). Farmers at higher the government encouraged smallholders to possession of livestock and altitude (Min altitudes (above 1000m) and those with more plant trees, smallholders preferred to plant rub- et al., 2017). Farmers with more plots of land widely spaced rubber trees were more likely to ber because rubber trees were (1) classified as were less likely to adopt intercropping, perhaps intercrop, but those with steep slopes were less forest cover by the government, and (2) could due to labor constraints. Indigenous minority likely to. provide income from latex without requiring farmers, who had traditionally practiced a high- additional logging/harvesting permits (Xu, ly diversified farming system in the same area, Although not directly related to adoption of 2006). Since 2003, China implemented forest were less likely to adopt intercropping prac- agroforestry or rubber-based agroforestry, tenure reforms which increased tenure security tices than relative newcomers to the region. land tenure reforms in China have influenced and increased length of tenure to forest land Farmers with greater income were more likely smallholder decisions to integrate rubber (from 15-30 to 70 years) for farmers. A study to adopt intercropping, but the magnitude of into their farming practices. The nationwide by Lin et al. (2020) found that tree planting change was very small (10% increase in income Household Responsibility System in 1978, which investments were significantly positively linked led to 0.7% increase in likelihood of adoption). allocated communal land to household-based to smallholders having full logging rights and Labor capacity had a strong positive effect tenure, led to an increase in smallholder-based not significantly affected by whether they had on adoption of intercropping, while many rubber monoculture plots in Xishuangbanna, a government-issued land certificate; although intercrops can be a source of livestock feed, mostly replacing swidden and rice, but also other socio-political factors likely come into explaining increased adoption among farmers intercropping immature rubber with rice, pine- play into smallholder decisions.75 with livestock. Farmers with off-farm livelihood apple and vegetables, creating a diverse mosaic activities were less likely to adopt intercropping landscape of rubber and other crops that allow

75 However, it has still proven difficult to persuade Chinese farmers to invest in native timber, possibly because of the recent history of political upheaval and distrust between the mi- norities who occupy the rubber growing areas and the Beijing Government (Email consultation, R. Harrison).

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BOX 9 DIFFERENCES IN ADOPTION OF RUBBER AGROFORESTRY IN NORTHERN AND SOUTHERN INDIA

Rubber farmers in Southern India and North- straints and a lack of time for additional crop- grated with upland paddy rice, fisheries, east India differ in their adoption of agrofor- ping; chosen intercrops had relatively low labor poultry, pigs and shifting cultivation. Adop- estry practices (Viswanathan and Shivakoti, requirements, and adoption of intercropping tion of diversified systems was much greater 2008). In Kerala, Southern India, a traditional was greatest in households with more family than in the south. It is not clear whether rubber rubber-growing region, 1-25% of farmers had labor availability. is intercropped, or whether the ‘diversifica- adopted intercropping with fruit trees, tim- tion’ of rubber-based livelihoods in this region ber, or pepper vines. Reasons for the In contrast, in Northeast India, where rubber is based on patches of rubber planted among dominance of monoculture practices in Kerala growing is a new phenomenon since the 1980s, other land uses. Rubber growing has provided included planting subsidies from the In- integrating rubber with other farming sys- financial security for farmers in this region, dian that restrict planting tems is much more common; communities improved food security by avoiding the need of secondary crops/trees in the holdings, in this region formerly practised shifting to sell rice in times of distress (selling rubber and land ownership policies (sub-division cultivation and rubber was promoted by instead) and providing cash income, allowing of inherited land into small holdings) that lead the Indian Rubber Board as way to cease livestock-rearing for both cash and consump- farmers to intensify and specialise production shifting cultivation practices. Land ten- tion. Institutional support for rubber monocul- on small areas of land (e.g. 0.5 ha holdings) ure in the Northeast is predominantly through ture had a negative effect on diversified rubber (Viswanathan and Shivakoti, 2008). In addition, village commons and communal ownership systems in Northeast India, as in Southern India. increasing household incomes means rubber (vs land titles in Southern India), and land is allo- Full-time farmers and those with more experi- is increasingly tapped using hired labor, rather cated for rubber cultivation in barren/marginal ence growing rubber were more likely to have than household labor, resulting in labor con- areas by village leaders, where rubber is inte- diversified systems.

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BOX 10 WIDESPREAD USE OF INTERCROPPING IN SRI LANKA

A survey of 587 smallholder rubber farmers increasing farm income, but high input costs understanding of the value of intercropping, in Sri Lanka assessed the prevalence of rub- were a potential barrier for increasing the and that this knowledge needed to be incor- ber-intercropping during immature phase planting density of banana intercrops to fur- porated into further research, for example of rubber. The percentage of smallholders ther increase profits. The authors noted that through the development of a participatory engaged in intercropping ranged from 23 to the widespread practice of multiple crop- research process at the Rubber Research In- 54% depending on location. Banana was the ping on homesteads in Sri Lanka suggests stitute of Sri Lanka (Rodrigo, Stirling, Naran- most common companion crop of rubber, that local farming systems already have an panawa, et al., 2001).

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BOX 11 MULTIPLE FACTORS AT PLAY IN FARMERS’ DECISIONS TO KEEP JUNGLE RUBBER OR TO CONVERT TO MONOCULTURE IN INDONESIA

A participatory on-farm research experiment ber. Therefore, contrary to expectations, farm- A computer-model-based study of jungle rub- on the establishment of clonal (high-yielding) ers opted to use plantation monoculture meth- ber agroforest conversion to monocultures in rubber planting stock in jungle rubber agro- ods to protect what they considered a valuable Indonesia investigated reasoning for conver- forests in Indonesia involved four farmers who asset (high-yielding rubber trees), rather than sion, and whether market-based instruments grew clonal rubber trees in 20 plots (Williams maintain the traditional multispecies strategy (such as premium prices for eco-certification, et al., 2001). Vertebrate pest damage by mon- they use with lower-yielding locally sourced carbon payments, taxes on particular conver- keys and wild pigs were the most important in- rubber trees (Williams et al., 2001). sion processes) could influence farmer choices. fluence on the establishment of the new rubber Risk-aversion by farmers influenced the deci- trees within jungle rubber agroforests, explain- In Kalimantan, Indonesia, initial interest in rub- sion to convert, with more risk-averse farmers ing ~70% of variation in rubber tree growth. The ber agroforestry and improved rubber growing choosing to retain a greater area of agrofor- amount of labor invested in weeding was also practices in 1994, that led to the establishment estry. However, multiple market-based instru- positively correlated with rubber tree growth: of an ICRAF experiment, has fallen away in fa- ments would still be needed to avoid any agro- farmers generally decided to completely cut vour of oil palm cultivation — however, many forest conversion; these would stabilise farmer back vegetation between rows of rubber trees, farmers had kept rubber on as a means to di- incomes, and reduce income inequality among including potentially valuable trees, rather than versify their farming, and valued agroforestry. farmers (Djanibekov and Villamor, 2017). weeding within the rows and selectively prun- However, knowledge of good tapping practices ing trees in the inter-row, as farmers considered to maintain yields, and availability of high-quality Other studies also found that gender roles and inter-row vegetation to harbour vertebrate clonal planting material, are still in short supply preferences affect whether jungle rubber was pests and compete with the new rubber trees. (thanks to abandonment of initiatives, such as converted to monocultures (Grace B Villamor Instead, farmers accessed fruits, firewood and farmer-led nurseries, since 1994 in favour of oil et al., 2014; Villamor et al., 2015; Grace B. Villam- other non-timber forest products from other palm development) (Penot and Ari, 2019). or and van Noordwijk, 2016) — see section on land, rather than retaining integration with rub- Gender 3.2.1).

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BOX 12 WHY DO SMALLHOLDERS IN SOUTHERN THAILAND ADOPT (OR NOT ADOPT) RUBBER INTERCROPPING SYSTEMS?

In a survey of 300 smallholder rubber farmers and sustainability. The authors suggests that in southern Thailand, 21 rubber agroforestry improving prices and markets for agroforestry systems were identified, with variable profit- products, developing technology to increase ability depending on secondary crop market productivity on rubber farms, increasing farm prices and input costs. Farmers made decisions efficiency and reducing risk rat the farm level, about rubber intercropping system based on and better co-ordination among stakeholder labor availability, knowledge and experience, agencies at the regional level are needed to fur- extension agencies and government policies, ther develop smallholder rubber agroforestry marketing opportunities for intercrops, capa- systems in Thailand (Somboonsuke et al., 2011). bility of local communities, land topography,

Rubber-fruit tree intercropping in Southern Thailand Credit: CC BY-NC 4.0 EWT

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4.2 RECOMMENDATIONS FOR WIDER ADOPTION OF RUBBER AGROFORESTRY

4.2.1 GENERAL RECOMMENDATIONS

4.2.1.1 UNDERSTANDING STAKEHOLDER NEEDS AND (e.g. timber) practical?), as well as long term At the same time, to promote cultural aware- ASPIRATIONS aspirations (e.g. do they want their children ness and knowledge of rubber agroforestry to continue farming?) Understanding small- among both rubber growers and purchasers/ Interviewees and experts stressed that it holder needs and local cultures are also key consumers, there is a need for better dissem- was essential to understand the needs, con- to improving food security and nutrition as ination of information about the benefits of straints, and interests of smallholders and well as other social outcomes (e.g. can inter- agroforestry.77 In particular, it is important to plantation managers to effectively implement cropping with vegetables or keeping chick- communicate that there are few cases where rubber agroforestry. Recommendations for ens in their rubber farms help them achieve yield decline was observed when rubber is agroforestry models and best practices will their nutrition needs?) Similarly, tailoring produced in agroforestry compared to mono- need to be tailored to the diverse situations recommendations by gender will likely im- culture systems. This information needs to be involved. Plantation managers, absentee prove uptake of agroforestry by women and accessible to local audiences and shareable, landowners, and smallholders will vary wide- enhance female participation in agroforestry e.g. via a documentary, local media debates, ly in their availability in financial capital and (e.g. by providing women-led training, or by video clips, and social media, especially if labor, access to markets, their short-term promoting intercropping of medicinal plants farming were to be promoted in the younger needs (e.g. do they require certain crops for traditionally associated with women’s roles in generation. If rubber agroforestry skills were subsistence? Do they require returns on a some communities).76 linked to social reputation, then it would also weekly/annual basis or are delayed returns become more attractive.78

76 Interview, Michael B. Commons. 77 Interviews, Sara Bumrungsri, Linda Preil. 78 Interview, Linda Preil.

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4.2.1.2 GOVERNMENT POLICIES meet their own needs. • Supporting the formation of farmer AND SUPPORT SYSTEMS networks, associations or cooperatives, More specifically, to facilitate wider adoption including women’s groups to enable infor- In general, government policies are needed to of rubber agroforestry among smallholders, mation exchange and better market access promote agricultural practices that have demon- several support systems are needed: strated environmental benefits (e.g. agroforest- ry), and to disincentivize or discourage unsus- • Government policies to allow innovation To improve food security, nutrition and tainable practices (e.g. unnecessary herbicide and agroforestry systems on farms, and gender equity outcomes, agroforestry poli- spraying on large areas of rubber plantations). to encourage agroforestry, e.g. a special cies should also explicitly include nutrition These policies need to be consistent (e.g. sub- loan system for agroforestry farmers to and gender equity based goals (FAO/IFAD/ sidies and technical recommendations should help them in the establishment phase; UNICEF/FFP/WHO, 2020). For example, to both favour agroforestry practices) and persis- provision of planting material and improve access to healthy diets in rural com- tent (not subject to changes in government). seedlings for intercrops in addition to munities, policies can be designed to support Policies to support agroforestry also need to rubber clones; subsidies intercropping of nutritious food crops (e.g. account for land-use planning and land tenure vegetables, legumes, fruit) and integration of policies, to avoid detrimental environmental • Dissemination of technical animal husbandry for protein (e.g. poultry, impacts (e.g. land-clearing for agroforestry) recommendations at the national level via fish) on existing rubber monocultures. and to support smallholders’ investments on extension services, or via farmer-to-farmer the land. In new rubber development frontiers approaches (peer-to-peer learning and In addition to supporting smallholders with where rubber trees are being introduced as a farmer visits to other farmers’ plots) material assistance and knowledge/training, new crop, proactive measures should be taken national rubber research institutes and ex- to encourage rubber agroforestry models as an • Having demonstration plots or tension agencies play an important role for alternative to monoculture plantations. Farm- model farms agroforestry research, including performing ers need to be listened to, and farmer-led ap- experimental field trials and having demon- proaches need to be developed, (e.g. as recom- • Support for marketing of agroforestry stration plots. In Nigeria, increased adop- mended in Sri Lanka, and attempted in Box 12 or intercrop products, removal of tion of agroforestry by farmers was linked in Indonesia), such that farmer knowledge and disincentives e.g. in domestic rattan to on-farm trial demonstrations, accessing traditions are sustained, food security and nu- market in Indonesia agricultural knowledge through training, ex- trition is ensured, and farmers have flexibility to tension contact, education level, membership

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of farm organization and attitudes towards to embrace additional indicators of sustain- • Temporary intercropping between rubber intercropping (Mesike, Esekhade and Idoko, ability around livelihoods, soils, biodiversity, rows during first three years of rubber 2019). Farmers in Sri Lanka were more like- and climate resilience. Agroforestry practices establishment. ly to adopt rubber intercropping if they had and systems can be a financially viable strat- more extension contacts and higher educa- egy to increase the environmental sustain- Plantation companies can trial these rubber tion (Herath & Takeya, 2003) in (Hondrade ability of rubber plantations, and improve agroforestry practices on a portion of their et al., 2017). livelihood outcomes for estate workers and estates, support rubber agroforestry tri- smallholders. Hence, we suggest that planta- als among smallholders via their outgrower Having an initial experimentation phase, tion companies invest in research and devel- schemes, or even provide access to parts of conducted by companies or research insti- opment to identify cost-effective agrofor- the plantation for rubber workers or their tutes, that would trial different designs and estry practices and publish these in their families to plant additional crops between different farming models and determine best sustainability reports to facilitate knowl- rubber rows. Plantation companies could also practices, would take the financial risk of edge exchange. Specifically, such practices offer additional training to rubber tapping experimentation off smallholders. Another should encourage efficient water use, prevent workers in agroforestry practises, for use on option is to fund or subsidize rubber agro- soil degradation and erosion, reduce wa- their own plots of land, or within the planta- forestry field trials on a group of smallholder ter pollution, and benefit biodiversity at the tion if provided access. farms, which can then serve as demonstration production site. Specific strategies, some of plots or model farms for other smallholders. which do not require agroforestry systems to In their role as societal enabler, plantation be fully established, include: companies should take a proactive role to fa- cilitate knowledge exchange for small-scale • Reduced weeding; rubber growers through funded workshops 4.2.1.3 INDUSTRY’S ROLE • Cover cropping; and development of best practice guidelines for diversified rubber systems. They should • Intercropping with crops that require Industrial and large-estate plantations make contracting arrangements with little maintenance; should make binding commitments for small-scale farmers that actively support sustainable rubber production. The sus- • Planting of riparian (stream/riverside) agricultural diversification. Ideally, compa- tainability reporting of rubber producing areas with a diversity of native and/or nies should encourage access to their plan- companies should move beyond improve- productive tree species; tation land for plantation workers to grow ments in energy, water, and carbon emissions, secondary crops. In all contracts and arrange-

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ments with small-scale farmers, companies tainable practices. Moreover, rubber buyers, rubber research institutes, CSOs, and the should publish a code of conduct on ecolog- such as tire companies, could facilitate the farmers they collect data from and work with, ical and social standards to ensure fair prac- adoption of agroforestry rubber by creat- to ensure knowledge is shared with those who tices, comply with national and international ing a demand for agroforestry rubber through can apply it. Meanwhile, researchers can also regulations, as well as spell out clear guide- procurement policies, and/or by facilitating learn from the practical knowledge of farmers lines for misconduct. the adoption of rubber eco-certification that which can better inform their studies, while grant a price premium for smallholders and at the same time uplifting farmer-produced Risk assessments, cost benefit analyses, and industrial growers who implement agrofor- knowledge and lived experiences. Research- eco-certification can aid companies to iden- estry and other sustainable practice. ers can assist farmers in gathering evidence tify and monetize the financial advantages of and supporting the presentation of evidence, agroforestry and other sustainable practices, helping to amplify the farmers’ voices on local and should be conducted as a standard prac- 4.2.1.4 RESEARCHERS or international policy platforms, particularly tice to highlight the importance of zero de- in situations and cultures where published forestation commitments and ecosystem ser- Positive, mutually beneficial relationships or accredited research is perceived as having vices protection. Many tools to aid businesses between the smallholders (and other non-re- high value and credibility and where farmer in conducting these assessmentsare available search stakeholders) and the research com- perspectives are underrepresented.82 The ev- for free. The Global Forest Watch tool 79 al- munity can help facilitate wider adoption idence presented on agroforestry effects on lows to assess the risk of in rub- of agroforestry. Local and international re- soils needs to be bolstered with more robust ber producing areas, while High Conservation searchers can co-create and support farmers studies, that encompass the wide variation Value (HCV) and High Carbon Stock (HCS) with well-evidenced agroforestry knowledge among smallholder rubber plots. Lastly, our approaches are useful for companies to as- and best practices, as well as help to iden- literature review has highlighted a major re- sess the ecological and carbon values in their tify and solve farmers’ problems, or help to search gap in the peer-reviewed rubber agro- holdings. The InVest tool 80 can help compa- connect farmers to other resources or col- forestry literature in terms of elucidating the nies to analyse the value of ecosystem servic- leagues.81 Researchers must make strong ef- links between rubber agroforestry and food es provided by agroforestry and other sus- forts to share their research findings with security and nutrition, gender equity and la-

79 Global Forest Watch (available at: https://www.globalforestwatch.org) 80 InVest (available at https://naturalcapitalproject.stanford.edu/software/invest) 81 Interview, Michael B. Commons. 82 Interview, Michael B. Commons.

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bor burdens, land tenure, and other social farmer networks provide mutual support dimensions (e.g. farmer empowerment, and more opportunities for accessing re- food sovereignty). sources via collective action, from develop- ing skills and inclusion of women and youth, and scaling out agroforestry practices. 4.2.1.5 FARMER NETWORKS Farmer-to-farmer networks and associa- In more general terms, research on farmer tions facilitate the spread of agroforestry networks is still limited. The effectiveness practices and knowledge in farming com- of collaborative networks between stake- munities. A quarter of surveyed farmers in holders to address environmental problem Southern Thailand adopted agroforestry are said to depend on individuals’ attitudes after hearing about successful experiments towards the benefits of knowledge sharing in their area by their peers (Stroesser et with others (e.g. some farmers may fear al., 2018). Farmers use diverse sources of that their hard-earned knowledge will be knowledge (including informal farmer net- “exploited” by other farmers), differences working, networking facilitated by formal in knowledge gaps, and whether such is- agricultural knowledge institutions, collab- sues can be overcome in a foreseeable time oration between farmers and researchers, period (for a review see (Bodin, 2017)). In and multidisciplinary knowledge networks), cocoa, farmer networks in Ghana have been but they lace high importance on local ex- shown to play an important role for knowl- periential knowledge because they view edge transfer (Isaac, 2012). For example, such knowledge as personally, locally, and rural communities relied exclusively on practically relevant (Šūmane et al., 2018). As knowledge exchange for agroecological such, farmers who have successfully adopt- production knowledge of cocoa. In clos- ed agroforestry practices are the best source er proximity to urban areas, farmers had of locally adapted, practical knowledge; and much closer contact with agri-environmen- tal organizations to facilitate knowledge about agroforestry (Isaac, 2012). Farmers Large (top) and small-scale (bottom) in networks with better access to informa- rubber smoke houses in Myanmar Credit: Both images: CC BY-NC 4.0 TCW 106 RUBBER AGROFORESTRY Discussion

tion had higher on-farm crop diversity. The support these transitions. Farmer represent- in Laos (2014) and Xishuangbanna (2016); authors argue further that policy promoting atives should be real farmers to ensure effec- joint online workshop on Natural Rubber diffuse and more innovation prone farmer tive implementation of agroforestry.83 Systems and Climate Change (2020);85 and network structures is strategic for persistent the upcoming International Workshop on the cocoa production systems. In Southern Thai- There should be a multi-way exchange of in- Resilience of Rubber-based Agroforestry Sys- land, rubber agroforest smallholder farmers formation regarding agroforestry best practic- tems in the Context of Global Change (April have formed groups around common inter- es among and between farmers, researchers, 2021).86 Input from industry, in terms of both ests (e.g. love for trees, wanting to increase CSOs, officials and industry. Some farmers agroforestry best practices and agroforestry income), which have facilitated the spread of are very knowledgeable about agroforestry transitions and value chain development is agroforestry among peers as well as collabo- and are creatively experimenting with dif- another piece of the puzzle. Such collabo- ration with researchers and industry (see case ferent agroforestry approaches and species ration will help consolidate the global and studies in Box 3 and Box 4). – their experience and creativity are valu- local knowledge base of agroforestry, help able sources of practical knowledge. Com- prevent pitfalls (there are many examples of munication with non-research stakeholders newly introduced promising species turning COLLABORATION 4.2.1.6 should be done via interpersonal meetings out in failed projects),87 facilitate joint learn- There is a need for collaboration between wherever possible, or possibly focus groups. ing and promote best practices, and scale multiple stakeholders to find integrated solu- At the same time, agroforestry researchers out agroforestry. An agroforestry-oriented tions to address the dynamic and complex from international agroforestry and rubber innovation platform was suggested as a way challenges for sustainable agriculture, not research institutes (e.g. CIRAD, ICRAF, IR- to facilitate such collaboration and informa- least including the wider adoption of agro- RDB), as well as experts from national rub- tion exchange. Funding or support from cli- forestry. This is because changes at different ber institutes84 should also come together to mate funders and multilateral agencies could scales and from different actors are needed – consolidate the global base of agroforestry help facilitate this. Farmer to farmer learning from cultural shifts among smallholders and knowledge. Examples of such collaborations is likely to be key, given the experiences of the estate companies, to government policies to include: “Green Rubber” conferences held farmer networks detailed above.

83 Interview, Sara Bumrungsri. 84 A lot of agroforestry research has been conducted by rubber research institutes but are not published, are documented in internal reports or in the local language, or are only available on the ground. Physical visits to these locations may be needed to compile this information (interview, Rhett Harrison). 85 Workshop materials and recordings are freely available at: https://www.foreststreesagroforestry.org/fta-event/natural-rubber-systems-and-climate-change/ 86 https://www.rubis-project.org/project-events/current-event/rubis-international-workshop-2021 87 Email consultation, Julia Quaedvlieg.

107 RUBBER AGROFORESTRY Discussion

All stakeholders, including BEST PRACTICES AND PITFALLS farmers, need to be recognized as 4.2.2 FOR RUBBER AGROFORESTRY equal co-authors of knowledge generation, and all kinds of There are no universal best agronom- 1 Constraints of local ic practices for agroforestry that will biophysical environment knowledge, both formal and work in every location. Experts found it informal, need be brought challenging to summarize best practic- When agroforestry practices are not es for rubber agroforestry, as they will adapted to the local biophysical condi- together in innovation processes. depend on a variety of factors and be tions, it could lead to yield and produc- Knowledge networking and multi- highly context dependent, including the tivity losses for rubber or the intercrops. local biophysical environment, market For example, intercropping with coffee actor knowledge networks that availability, smallholder needs and con- and cocoa at normal rubber planting facilitate knowledge exchanges, straints, as well as the objective or rea- density does not work; intercropping in sons for utilising agroforestry strategies. sandy soils would lead to competition joint learning and the generation Similarly, pitfalls occur when these for water).88 of new more integrated solutions, factors are not considered when im- plementing rubber agroforestry practic- Market availability are crucial if agriculture is to es. As discussed earlier, understanding 2 become sustainable and resilient.” stakeholder needs and aspirations are If the additional products from agro- key. To be effective, agroforestry prac- forestry have no market or utility in the Šūmane et al., 2018 tices or systems should account for: area, then it is unlikely to contribute to incomes or livelihoods, even if these crops or livestock can grow well in the

88 Interview, Eric Penot.

108 RUBBER AGROFORESTRY Discussion

rubber plots. Conversely, agroforestry prod- will be needed for different objectives, as de- usually the key cash crop), not planting trees ucts that already have established demand termined by smallholders or industrial plan- that would shade out the rubber trees, and and local markets, or which can be used di- tations. Agroforestry strategies for ecosystem not planting other intercrops in the rubber rectly by smallholders, would be more likely restoration and biodiversity may look very line (see earlier section ‘Yields and Produc- to be successful. different from agroforestry strategies purely tivity’ for a more detailed discussion). For to increase economic returns. pitfalls of rubber-based intercropping, Lan- genberger et al. (2017) reviews several exam- Smallholder needs and 3 Given the diversity of situations and agro- ples that have not worked well in economic or constraints forestry systems, this report does not pro- agronomic terms. Smallholder needs will determine the objec- vide a list of technical recommendations for tive of adopting agroforestry practices and best practices and there is still a lot to do to For industrial plantations, interviewees sug- systems (e.g. is it to grow food for self-con- identify the best practices in the different gested that rubber-timber intercropping sys- sumption, or for improving soil quality, or socio-economic and biophysical conditions. tems had the most potential for scaling up to diversify income?). Gender differences Nevertheless, several researchers and prac- due to the high economic returns and lower should be considered, particularly in terms titioners interviewed maintain that strate- labor needed.90 These systems can also work of labor constraints which are key, as well as gies for avoiding reduction in rubber yields well for smallholders who wish to invest less land constraints, tenure conditions, govern- and increasing productivity in intercropping labor and who are able to accept delayed re- ment policies, etc. systems have been established by prior re- turns.91 However, these may compete with search.89 These include: double-row alley the rubber canopy, and although they could cropping with wider interspacing for inter- increase profits, no evidence has yet shown Agroforestry objectives 4 crops (therefore maintaining overall planting benefits for soil, water or biodiversity of rub- Different agroforestry practices or systems density of rubber across the farm, as rubber is ber-timber systems.

89 Interviews, Rhett Harrison, Eric Penot, and Michael B. Commons. Email consultation, Bénédicte Chambon. 90 Interviews, R. Harrison, E. Penot, and M. Commons. Also discussed in Langenberger et al. (2017). 91 Interview, R. Harrison.

109 RUBBER AGROFORESTRY Conclusions

Precautions are therefore needed in designing and managing these systems: Conclusions farmers’ expectations, in 5

contexts that are determined Rubber agroforestry systems are dynam- ades to produce results. In contrast, the at once by social, economic ic and versatile, consisting of multiple need for action to support smallholder components that make contributions to farmer livelihoods and build climate-re- and political factors, must not smallholder livelihoods, food security silient and more biodiversity-friendly be ignored, and agroforestry and nutrition, provide social advantages, rubber cultivation practices is urgent. and improvements for soils, water and systems should not be other environmental and climate out- Better information sharing is needed, exclusively geared to comes. Research gaps still exist around for example through farmer-to-farm- the ‘best’ practices for agroforestry such er exchanges, the opening up of rubber productivity. Agroforestry as appropriate intercrops, optimal tree research institute reports and knowl- cannot evolve as an spacing, and water usage; as well as the edge into the public domain, and better social outcomes of agroforestry such as translation of scientific studies into us- environmental concept if it is gender, food security and sovereignty, er-friendly materials for use by govern- voided of its most fundamental nutrition, and farmer empowerment. ment agencies and businesses. For ex- However, one of the take-home messag- ample, farmers in Lao PDR are already goal, which is to bring es from this report is that there is already skilled at producing food from diversified sustainable improvements to considerable knowledge around agrofor- shifting cultivation systems – this knowl- estry systems that can be used, and while edge is at risk of loss due to restrictive farming livelihoods.” controlled experimental systems would rubber planting contracts. In other loca- be hugely beneficial, these may take dec- tions, such as Southern Thailand, farm-

Barisaux, 2017

110 RUBBER AGROFORESTRY Conclusions

ers went through a policy-driven transition them. Multiple projects have trialled rubber menting agroforestry practices on estates, from cultivating diversified but low-yielding agroforestry practices, but have found it not and rubber buyers play a crucial role in facil- rubber systems to successful cultivation of to be widely adopted. This may not indicate itating demand and developing value chains monocultures, but some are using their prior that rubber agroforestry itself is untenable, for agroforestry rubber. Lastly, it is impor- knowledge, and that from other cropping sys- because ample evidence suggests that for ex- tant to note that agroforestry is not the only tems, to inform interplanting techniques in ample rubber yields in intercropping systems agroecological option to more resilient and higher yielding rubber agroforestry systems. are not lower compared to monocultures but environmentally friendly rubber production. Meanwhile, scientific studies of soil nutrients, income risk is more diversified in agroforest- Reduced weeding, cover cropping or planting soil carbon and water use from intercropping ry system. It rather shows that farmers did of riparian areas with trees are options inde- systems in China can support anecdotal ev- not have access to the information, knowl- pendent of agroforestry practices. idence from other locations (e.g. southern edge, networks, capital or physical inputs Thailand) that permanent intercropping can (e.g. seedlings) needed to diversify in the Overall, creating an environment where facilitate water use by rubber trees, although first place, that policy or market conditions farmers have access to information, capital, caution is needed in very drought-prone areas were not right for agroforestry to work more markets and importantly, the autonomy to (e.g. north-eastern Thailand). widely, or that farmers’ preferences and mo- choose which components of agroforestry tivations were not well understood. Rubber is best suit their needs and constraints would A precautionary approach is needed in the a long-term investment, but with short term allow them to exercise creativity and sover- adoption of all agroforestry practices. Agro- price volatility. Lessons must be learned from eignty in their farms and livelihoods. In the forestry systems that meet the needs of farm- places where rubber cultivation has generat- UN Decade of Restoration, learning from ers in specific locations are best designed ed long-term benefits for farmers and where existing agroforestry systems and taking on by those farmers, who know the constraints agroforestry practices are reaping rewards the challenge to establish new ones has the on labor, land or other resources they al- for farmers, such as in southern Thailand or potential to make a substantial contribu- ready have to manage, and the risks to their China, as well as places where existing agro- tion to bring sustainable improvements livelihoods that they already face. However, forestry practices are being lost, such as Indo- to the environment and farming liveli- better exchange of knowledge could help in- nesia, to inform rubber sustainability efforts hoods, if all stakeholders unite to build a form farmers of their options for diversifica- now. Similarly, there is much potential for better tomorrow. tion, and choose systems that work best for plantation companies to benefit from imple-

111 RUBBER AGROFORESTRY Methodology

6 Methodology

This report was written based on an extensive other grey literature. We also sought sugges- 6.2 INTERVIEWS literature search, interviews and email con- tions from interviewed experts and our wider AND EMAIL sultation with experts in rubber production, network for pertinent reports and hard-to- CONSULTATIONS and based on personal experience researching access academic papers. More than 800 ar- rubber production systems and agroforests in ticles were captured in this literature search, In October 2020, we sent out 35 requests for Latin America, Africa, and Southeast Asia. which were then filtered by specific topics interview or email consultations to stake- covered in this report. Around a third of these holders with knowledge or experience with articles have been published in the past five rubber agroforestry, from rubber research years alone (2015-2020), representing an up- institutes, CSOs, and industry. We were able 6.1 LITERATURE surge in interest in sustainability of rubber to consult with 12 interviewees with agrofor- REVIEW production. The majority of articles covered estry experience covering Asia (Indonesia, agronomic and environmental aspects of rub- Malaysia, Thailand, Cambodia, China), Afri- In October 2020, we conducted a literature ber agroforestry, with much fewer articles on ca (Nigeria, Cote d’Ivoire), and South Amer- search on Web of Science and Scopus, using socio-political or cultural aspects, as reflected ica (Brazil, Peru). We conducted in-depth, the search terms: in our Findings. semi-structured interviews with 10 stake- holders and received four written responses “TITLE-ABS-KEY ( ( rubber OR hevea ) AND We acknowledge there were additional poten- to a questionnaire (available from authors on ( agroforest* OR intercrop* OR inter-crop* tial sources of rubber agroforestry literature request). Regretfully, due to time and logis- OR agroecolog* ) OR “jungle rubber” OR which were not covered by Web of Science tical constraints, we were unable to consult “rubber garden” )”. and Scopus, particularly journals of national a broader range of stakeholders, particular- rubber research institutes, which we did not ly those who would require in-person visits We included conference proceedings in the manage to cover. (farmer associations, CSOs, and industry), as search, and also used Google Scholar to sup- well as additional rubber agroforestry experts plement our search with recent reports and from other countries not represented here.

112 RUBBER AGROFORESTRY References

Better representation of farmers’ ideas and Institute of Nigeria (email consultation Uraiwan Tongkaemkaew (interviewed perceptions of agroforestry should be a key 7/10/2020; interviewed 16/10/2020) 14/10/2020) focus for further research on agroforestry. Luciana dos Santos Duarte, Erasmus Uni- Practitioner/NGO versity of Rotterdam (ISS-EUR) (interviewed Researchers 11/10/2020; follow-up email consultation Michael B. Commons, agroforestry practi- Eric Penot, CIRAD (email consultation 16/10/2020) tioner, Earth Net Foundation (interviewed 15/10/2020) 8/10/2020; interviewed 12/10/2020) Julia Quaedvlieg, Erasmus University of Bénédicte Chambon, CIRAD (email consul- Rotterdam (ISS-EUR) (email consultation Anonymous (interviewed 6/10/2020) tation 9/10/2020) 15/10/2020) Industry Gerhard Langenberger, GIZ (interviewed Rhett Harrison (interviewed 9/10/2020) Linda Preil, Head of Rubber Projects, ein- 5/10/2020) Sara Bumrungsri (interviewed 12/10/2020) horn (interviewed 9/10/2020) Kenneth Omokhafe, Rubber Research

7 References

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124 RUBBER AGROFORESTRY Acknowledgements

8 Acknowledgements

We are deeply grateful to the interviewees for their time, and to farmer networks in Southern Thailand who informed and participated in previous research by one of the report authors (EWT). We hope that this report can contribute to the wellbeing of rubber producers everywhere and make a contribution towards more sustainable rubber production globally.

Thanks to Heather Weiss and Alex Wijeratna for editing this report, and for input from Dr Julian Oram, Margaret Kran-Annexstein and Aiyana Bodi from Mighty Earth.

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