Analysis of forest change trajectory and the causes in the core area of Changbai Mountains, China

Old-growth forests decline is one of the most important environmental issues in Northeast China. The present study was carried out in the core area of Changbai Mountains. Topographic maps, Landsat images acquired over a period of 53 years were used for cover change detection. The results showed that the forests decreased by 743.43 km² from 1954 to 2006. The annual decrease rate of forest land was 0.09%. Forests experienced the process of substantial clearing and fragmentation. Trajectories at every pixel were acquired to trace the history of forest change. The representative trajectories were conversions of forest to cropland and grassland to forest. As the slope gradient increased, the forest change area decreased. Forest changes are negatively and exponentially related to the distance to the residential lands and major roads.