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Opportunity cost analysis of land use changes in Karen indigenous community in Thailand
°Jintana Kawasaki1, Yasuo Takahashi1, Henry Scheyvens1 and Prasert Trakansphakon2

Karen indigenous people most living in and around the state forests in northern Thailand have long been practicing the traditional rotation farming (RF) for their subsistence food. However, the policies of government to conserve forests and to increase commercial mono-cropping have reduced the areas where Karen people have been managing with their traditional RF system, and have led to encroachment of forestland for cultivation. The Institute for Global Environmental Strategies (IGES), Japan, in partnership with the Indigenous Knowledge and People Foundation (IKAP), Thailand jointly conducted a study to assess the potential of land use changes from opportunity costs and carbon stock enhancement. The opportunity costs of land use changes were estimated from net present value (NPV) and total carbon dioxide of each type of land use. Data were collected from a field survey and interviews of 17 villagers in Mae Yod village, Chiang Mai province in 2015. The survey found that traditional RF system was increasingly converted to intensive monocrop agriculture such as maize and Azuki bean fields over the past five years, and while some of RF fields were abandoned for the forests because of the labor constraint. Changes of land uses in the research site were classified into three types: RF fields to forest land, RF to Azuki bean, and RF to maize.
We calculated the NPV per ha of Adzuki bean and maize from annual harvest incomes, the NPV of RF from non-market values of upland rice, and the NPV of FL from values of non-timber forest products, with a 20-year timeframe and a discount rate of 5%. Average above-ground carbon stocks (ton/ha) from previous studies and a land use data of Mae Yod village for 2015 were used to estimate total carbon stocks of each type of land use. The results showed that the highest NPV per ha per year was Azuki bean (US$ 998) due to higher amount of yields and prices, followed by maize (US$ 306), RF (US$ 208) and forest land (US$ 1.06). Total above-ground carbon stocks of forests (240 ton/ha) at the research site was higher than the RF (106 ton/ha), and permanent fields of maize and Azuki bean (65 ton/ha). The traditional RF were found not only to contribute to high levels of biodiversity and food for the subsistence of the Karen community, but also resulted in high carbon stocks. Total carbon stocks was converted into total carbon dioxide by constant “3.664”. Using the results of NPV (US$/ha/year) and total carbon dioxide (tonCO2e/ha) to estimate the opportunity cost of land use changes, the highest opportunity cost was the avoidance of changes from the RF to Azuki bean (US$ 5.25 tonCO2e), followed by from the RF to maize (US$ 0.65 tonCO2e), and from the RF to forest land (US$ 0.42 tonCO2e). Due to yearly incomes from the traditional RF are lower than Azuki bean and maize, which leads to a long-term reduction in the traditional RF practices. These results suggest that the government should consider traditional agroecosystems to avoid deforestation and ensure that a policy on commercial mono-cropping does not undermine its food security and diverse ecosystem services.

Key words: Trade-off, carbon stocks, land use changes
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1Natural Resources and Ecosystem Services Area, Institute for Global Environmental Strategies, Hayama, Kanagawa, 240-0115, Japan
2Indigenous Knowledge and People Foundation (IKAP), Chiang Mai, 50210, Thailand