Land use and forested landscape changes at Sakaerat Environmental Research Station in Nakhorn Ratchasima Province, Thailand

The Sakaerat Environmental Research Station (SERS) was established to promote long-term ecological research (LTER) and to demonstrate sustainable forest management and biodiversity conservation. In the past decade, the government puts a lot of efforts to rehabilitate degraded forest both inside and surrounding the SERS landscape in order to link fragmented forest patches. However, there is a lack of appropriate methods that allow the measurement of the effectiveness of reforestation. The objective of this paper is to quantify land use and landscape structure changes between 1990 and 2002. The study area encompasses the SERS and its buffer zone. Land use/land cover maps were visually interpreted into 9 classes using temporal Landsat-TM images. These classes include dry evergreen forest, mixed deciduous forest, dry dipterocarp forest, secondary growth, plantation, grassland, old clearing, agriculture & settlement, and water body. In addition, Geographic Information (GIS) and FRAGSTATS package were used to assess fragmentation indices. The results revealed that the annual increment rate of dry evergreen forest and dry dipterocarp forest were 0.51% and 0.97%, respectively. In addition, the surface area of forest plantation gained roughly three times or increased 193.23% during this period. On the other hand, agricultural and settlement area decreases 7.56% per year, most area was replaced by plantation and natural regeneration. The fragmentation indices indicated that the remaining dry evergreen forest was highly aggregated or low fragmentation. The number of patches decreased from 7 to 5 patches and mean patch size increased significantly. However, mixed deciduous forest and dry dipterocarp forest showed relative fragmentation. Mixed deciduous forest showed higher fragmentation. Mean patch size area was substantially decreased from 293 ha in 1990 to 123 ha in 2002 and the mean nearest neighbour distance increased approximately 400 m during this period.