Developing indicators of economic value and biodiversity loss for rubber plantations in Xishuangbanna, southwest China: A case study from Menglun township
Introduction
Economic development can be achieved through holistic management of natural resources, using reasonable cost-benefit analyses that incorporate opportunity costs of both economic and ecosystem benefits. In rural areas, economic growth is often achieved through agricultural intensification and the introduction of monoculture cash crops (Manivong and Cramb, 2008, Feintrenie et al., 2010). In Xishuangbanna, southwest China, monoculture rubber (Hevea brasiliensis) plantations have expanded dramatically over the past two decades, particularly in the species rich lowlands (Li and Yuan, 2008, Qiu, 2009, Ziegler et al., 2009). Rubber is indigenous to the tropical Amazon Basin and later on was largely introduced to China in 1950s (Xu, 2006, Xu and Yi, 2013). Initially, the Chinese central government established rubber plantations in this autonomous prefecture under the direction of the Ministry of Land Reclamation of Yunnan because natural rubber was regarded as an essential resource and critically important to national security (Xu, 2006, Sturgeon and Menzies, 2008). Partially in response to the U.S. trade embargo in the early 1950s, the Mengxing State Farm was created in the Menglun township (Fig. 1). After forestry reform in 1983, smallholder rubber plantations were initiated by villagers in Menglun assisted by technical guidance from the state-farm and government subsidies. Current proportion of rubber monoculture between smallholder and state-farm is 60–40%.
Immediate economic benefit and access to major new sources of revenue are often major drivers of rapid agricultural intensification of monoculture plantations. Rubber plantations in China are generally quite profitable and have provided considerable cash income to rural villagers in Xishuangbanna, who have few alternative sources of income (Qiu, 2009). These factors have led to the dramatic conversion of the majority of natural forests outside of protected areas to rubber monoculture plantations (Li et al., 2008, Liu et al., 2005). The strength of the economic incentive has even driven local smallholders to replace more traditional subsistence and cash crops, like corn, rice, and tea with rubber plantations. Additionally, the continued development of cold-resistant varieties has pushed rubber plantations into higher elevation areas and onto steep slopes, which are poorly suited for rubber production (Li and Yuan, 2008). Previous studies on the island of Hainan, China, have shown that monoculture rubber plantations on steep and hilly lands resulted in increased soil erosion (Gong, 2003), soil nutrient loss, reduced stream volume, and runoff becoming more seasonal (He and Huang, 1987, Zhang et al., 2000, Cha, 2005). Rubber trees withdraw water longer than natural vegetation during the dry season, leading to greater depletion of water in the deep soil (Guardiola-Claramonte et al., 2010).
Because rubber can be successfully grown in only a small portion of southern tropical China, the strong domestic demand for rubber combined with government policies has caused substantial natural forest loss in one of China's most biodiverse areas (Liu et al., 1998, Li and Yuan, 2008). Xishuangbanna is part of the globally recognized Indo-Burma biodiversity hotspot (Myers et al., 2000) and its natural forests contain a disproportionate fraction of China's biodiversity, given its small land area (Liu et al., 2001). The prefecture has been promoted as one of 32 territorial biodiversity conservation priorities by the Ministry of Environmental Protection emphasized in the 2011–2030 China Biodiversity Conservation Strategy and Action Plan. But rapid conversion of forest to rubber plantation now presents a serious threat to China's biodiversity (Chen and Wu, 2009, Ziegler et al., 2009). Therefore, the local government is caught between two conflicting objectives: the need for rapid economic development of the rural poor with rubber viewed as a national security issue against the environmentally damaging effects of monoculture plantations on natural forests, ecosystem services and biodiversity.
The local government, in collaboration with scientists from Xishuangbanna Tropical Botanical Garden (XTBG), has been exploring policy mechanisms to control forest conversion and provide economic incentives for forest restoration. The environmental impact of rubber plantations is significant but the incurred costs are difficult to quantify because they are external to economic accounting, particularly the loss of water storage capacity (Cha, 2005), increased soil erosion (He and Huang, 1987, Zhang et al., 2006) and environmental degradation (Zhang et al., 2000, Qiu, 2009). Additionally, these hidden costs take many years to reach their full impact, e.g. reductions in foggy days from the 1950s to the present (Gong and Ling, 1996, Wu and Yang, 2001, Zhou et al., 2006) and water shortage at high elevations since 2000 (Wu and Yang, 2001, Yang and Qin, 2009). Developing policy to create the proper incentives for sustainable management and protection of natural forest is difficult (Engel et al., 2008, Kelsey and Carolyn, 2008), particularly given the rapid development of China's market economy and growing autonomy of rural landholders through China's forest tenure reform (Rozelle et al., 2003, Xu, 2008).
To establish an economic indicator for rubber planting area and as a first step toward understanding the financial feasibility of any policy to promote reforestation in Xishuangbanna, whether based on compensation schemes or ecosystem service evaluation, we performed an analysis of the productivity and net present value (NPV) of rubber plantations in Menglun Township, Xishuangbanna. NPV is a time series analysis of cash flow for a given investment, comparing the initial value of the investment to the expected reward over the investment's lifespan, given some social discount rate (Butler et al., 2009). The township represents an ideal location for the study because Mengxing State-Farm is the one of oldest managed rubber plantations in China and the ongoing conversion of natural forests into rubber plantations by independent smallholder has been dramatic, including considerable encroachment on marginal lands. This allows direct comparison of rubber productivity between two well-established management systems, due to Mengxing State-farm being a good example of state farmed rubber, it has became a showcase in the region.
To assist the local government's initiative to develop a detailed and reasonable policy to promote reforestation, we generated spatially explicit maps of the net present value (NPV) of rubber plantations under both the state-farm and smallholder management systems, for the entire township. From these maps, we identified those areas where rubber plantations are least likely to be profitable over 25 years and we determined the scale of economic incentive required to promote forest restoration. Additionally, we directly compared landscape level indicators of biodiversity (Liu et al., 2007) to rubber NPV to address whether sites with high diversity directly conflict with sites of high profitability. As maintenance of biodiversity is central to most conservation schemes, identifying locations where stated management objectives directly conflict will be useful in resolving these issues and establishing necessary compensation mechanisms.
While the use of eco-compensation schemes or payment for ecosystem services are attractive ideas, if the profitability of rubber plantations is substantially greater than benefits provided by these mechanisms, then market-based incentives are likely doomed to fail. In this case, more top-down control mechanisms would be required to restore and maintain natural forests with their associated ecosystem services and high levels of biodiversity providing adequate justification for these additional funds. For example, the Chinese State Forestry Administration has recommended that monoculture rubber plantations within a 200 m wide buffer zone on either side of main roads, highways and rivers be replaced with natural vegetation (China, 2003a, China, 2003b). In these “buffer zones”, profitability may be high and therefore more direct payments may be necessary. On the other hand, the profitability of rubber, particularly on marginal lands, may be exaggerated and market-based policies for eco-compensation may be reasonably competitive in these “low productivity sites”, regardless of biodiversity indicators. Our spatial map of projected rubber NPV can assist local governments in evaluating these issues.
We also ask several other key questions related to these issues: What is the spatial variability in net present value or rubber plantations across the township? What is the opportunity cost associated with two types of targets for forest restoration; 1) “low productivity sites” where NPV is generally negative and 2) “buffer zones” of 200 m along major roads, highways, and rivers, as recommended by the Chinese State Forestry Administration? How does our model for rubber NPV compare with landscape- level indicators of biodiversity and where do these two values conflict spatially?
Section snippets
Study area
Menglun Township (total area = 335 km2) is located in central Xishuangbanna, south-west China, which borders the People's Democratic Republic of Laos and Myanmar (Fig. 1). Elevation ranges between 517 and 1541 m with an average temperature between 20° and 22.5° and the highest summer temperature being between 25° and 27°. Annual precipitation varies between 1200 and 1800 mm, with a wet season lasting from May to October during which 90% of the precipitation falls. The Xishuangbanna climate is quite
Spatially explicit map of NPV
Site- specific NPV was strongly affected by aspect, slope, age of trees, rainfall and mean temperature (Table 1). Predictably, plantations with a southern aspect had higher productivity due to the increased solar radiation. Steep slopes were significantly lower in productivity, probably due to poor soil nutrients and water status. Latex productivity also varies with tree age, increasing until middle-age (18 years in smallholder, and 27 years in the state-farm) and then declining slowly. The
Discussion
China is among the world's top consumers of natural rubber and the central government has listed rubber as a key strategic natural resource. Domestic production of rubber in China is limited to tropical areas rich in biodiversity, i.e., Xishuangbanna and Hainan. Rapid conversion over the last two decades has left little remaining natural forest outside of protected areas (Liu et al., 2005, Liu et al., 2006, Li, 2007, Li et al., 2008, Qiu, 2009, Ziegler et al., 2009). Simultaneously,
Conclusions
Our study highlights the spatial variability of economic benefits from rubber. Even though conversion can lead to substantial profits, the ultimate return is site- specific. A detailed spatially explicit analysis can identify those locations where NPV is negative or vulnerable to market fluctuations and eco-compensation mechanisms will work effectively. Additionally, because biodiversity richness and economic benefit are often highest in the same locations, our approach provides a direct
Acknowledgements
This research was funded by Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences and by grants from the Chinese Academy of Sciences’ Frontiers in Innovative Research to Charles H. Cannon. Part of the funding for this work was generously provided by GIZ/BMZ Making the Mekong Connected, Project No. 08.7860.3-001.00. Part of the funding, for classification of satellite imagery, in this work was generously provided by the Federal Ministry for Economic Cooperation and Development,
References (64)
- et al.
Designing payments for environmental services in theory and practice: an overview of the issues
Ecol. Econ.
(2008) - et al.
Past, present and future land-use in Xishuangbanna, China and the implication for carbon dynamics
Forest Ecol. Manag.
(2008) - et al.
Mapping rubber tree growth in mainland Southeast Asia using time-series MODIS 250 m NDVI and statistical data
Appl. Geogr.
(2012) Large-scale altitudinal gradient of natural rubber production in Vietnam
Ind. Crops Prod.
(2013)- et al.
- Butler, R.A., 2008a. Amazon Palm Oil: Palm Oil Industry Moves into the Amazon Rainforest,...
- Butler, R.A., 2008b. In: Butler, R. (Ed.), South Korea to Lease Half of Madagascar's Arable Land for Corn, Oil Palm...
- et al.
REDD in the red: palm oil could undermine carbon payment schemes
Conserv. Lett.
(2009)
Sustainable land management practices for rubber plantations in Mountainous Area of Hainan
Pedosphere
Ecological issues and loss risk of cold-resistant rubber germplasm resource in Xishuangbanna
Chin. J. Appl. Ecol.
The Main Technology for Forest Resource Investigation
The Main Technology for Forest Resource Investigation
Fog decreasing in Xishuangbanna region
Meteorol. Monthly
Land use-related changes in soils of Hainan Island during the past half century
Pedosphere
Does “jungle rubber” deserve its name? An analysis of rubber agroforestry systems in southeast Sumatra
Agroforestry Systems
Modified BEAM rubber agrogorestry models: RRYIELD AND RRECON. Australian Centre for International Agricultural Research
Canberra
Hydrologic effects of the expansion of rubber (Hevea brasiliensis) in a tropical catchment
Ecohydrology
Economic development, land use and biodiversity change in the tropical mountains of Xishuangbanna, Yunnan, Southwest China
Environ. Sci. Policy
Rubber Cultivation at the North Fringe of the Tropics
Very high resolution interpolated climate surfaces for global land areas
Int. J. Climatol.
Synthetic Rubber Manual
Designing payments for ecosystem services: Lessons from previous experience with incentive-based mechanisms PNAS
Is oil palm agriculture really destroying tropical biodiversity?
Conserv. Lett.
Rubber plantations – green desert
Chin. Natl. Geogr.
Exploitation and utilization of land resources in Xishuangbanna: rubber tree and water
Jo. Yunnan Trop. Crop Sci. & Tech.
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