Between 2000 and 2013, global production of natural rubber, which is made from the latex produced by Hevea brasiliensis, almost doubled from just under 7 million tonnes to over 12 million tonnes per year, stimulated by the ever-increasing demand for tyres, condoms and other products which are made with a mix of natural and synthetic rubber. Approximately 80% of natural rubber comes from five Asian countries.
“Rubber is a very valuable smallholder crop, and a pathway out of poverty for many rural communities,” says Rhett Harrison, a World Agroforestry Centre ecologist based in China. “However, when it’s grown as a monoculture, it can do a lot of damage to soils and water. We need to encourage systems of rubber agroforestry which have less impact on the environment and increase the environmental services they provide.”
This is the aim of the 3-year Green Rubber Project, which is managed by the Centre and funded by GIZ. As demand for rubber has increased, the crop has spread beyond peninsular Malaysia into the Upper Mekong, and there are now significant areas under rubber in Cambodia, China, Laos, northern Thailand and Vietnam. Rubber has begun to replace traditional farming systems, especially swidden agriculture, and large areas of natural forest in an area which is rich in biodiversity hotspots.
The first year of the project was devoted to gathering background information. Teams of researchers conducted socioeconomic household surveys at two sites in Xishuangbanna in China; similar surveys will be carried out in 2015 in Laos and Thailand. The surveys overlap with work being carried out in the Upper Mekong Sentinel Landscape and include an extra module on rubber production, to provide an insight into the impact on local economies.
Researchers have begun collecting data on gender issues, greenhouse gas emissions in rubber plantations, and fungal diversity and soil health. There is also a GIS component whose aim is to improve the mapping of rubber by identifying the age of plantations. Older plantations tend to be richer in biodiversity, and provide a greater range of ecosystem services, than young plantations.
From monoculture to agroforestry
These and other studies are helping Rhett and his colleagues establish a comprehensive database about the impact of rubber plantations – both positive and negative – on local communities and the environment in the Upper Mekong. “Our next step is to start exploring how agroforestry can create a more environmentally sustainable form of rubber production,” says Rhett.
Rubber agroforestry is already practised in parts of southern Thailand, where farmers plant a range of timber and fruit trees alongside their rubber. This provides them with a more diverse source of income, which is particularly important as rubber prices frequently fluctuate. Shortly before the Green Rubber Project began, rubber was fetching over US$7 per kilo on the world market. Now it is back to just over US$1 per kilo, much closer to its long-term average. This works in favour of the project, as farmers are unlikely to consider alternatives to rubber monoculture when prices are very high.
“We would like to introduce something similar to the rubber agroforestry practices in southern Thailand in the Upper Mekong,” says Rhett. “However, we want to do it more scientifically, and test a range of different agroforestry systems that will help to address environmental problems without threatening the commercial viability of rubber as a crop.” This could involve planting timber trees in and among the rubber, and encouraging farmers to leave corridors as “regenerating jungle” between rows of rubber.
Agroforestry can create a more environmentally sustainable form of rubber production
In October 2014, a 4-day workshop on ‘Sustainability of Natural Rubber in the 21st Century’ was held in Vientiane, Laos. Hosted by the National University of Laos and the Laos Ministry of Agriculture and Forestry, and co-organized by the Green Rubber Project, the event attracted some 90 participants. The workshop created an exchange platform to link institutes and organizations working on rubber. It also increased the visibility of current research and identified options for future collaboration. The platform will meet again in 2016. “One of our long-term aims involves launching a multi-site experiment which will evaluate the benefits of rubber agroforestry in the region,” says Rhett.
