Land use and above-ground biomass changes in a mountain ecosystem, northern Thailand

Abstract

The conversion of forests into agricultural lands is a major cause of deforestation, particularly in the mountain ecosystems of northern Thailand. It results in a rapid loss of biological diversity of both flora and fauna. In addition, the above-ground biomass (AGB), which can be a major source of carbon storage, is also decreased. This study aimed to predict the AGB in Doi Suthep-Pui National Park, Chiang Mai province, based on land-use/land cover (LULC) changes from 2000 to 2030. Landsat-5 TM (2000) and Landsat-8 TM (2015) satellite images were analyzed to predict LULC changes to 2030. Temporary plots (30 m × 30 m) were established in each LULC type for AGB analysis; trees with diameters at breast height ≥ 4.5 cm were identified and measured. AGB of all LULC types were analyzed based on specific allometric equations of each type. The results show that area of forest and non-forested areas fluctuated during the study period. Through the first 15 years (2000–2015), 5% (2.9 km2) of forest changed to either agriculture or urban lands, especially mixed deciduous forest and lower montane forest. There was a similar trend in the 2030 prediction, showing the effect of forest fragmentation and the resultant high number of patches. Total AGB tended to decrease over the 30-year period from 12.5 to 10.6 t ha−1 in the first and second periods, respectively. Deforestation was the main factor influencing the loss of AGB (30.6 t ha−1) related to LULC changes. Furthermore, habitat loss would be expected to result in decreased biological diversity. Consequently, a management plan should be developed to avoid unsustainable land use changes, which may adversely affect human well-being.