干旱区生态环境知识资源中心

The Three-North Shelter Forest Region (TNSFR) of China exhibits obvious forest cover changes that have been caused by numerous government-led afforestation and reforestation projects in recent decades. This study investigated the forest cover changes in the TNSFR during 1990-2005 based on a land cover dataset developed by the Chinese Academy of Science using remote sensing data and analyzed its relationship with meteorological change trends. The results indicated that the total forest area increased by 1.64 million ha (26.98 to 28.62 million ha) from 1990 to 2005. The composition of forest cover types of dense forest, shrubs, sparse forest and other forest remained approximately consistent over time, and the dominant cover type was dense forest. There was a uniform spatial distribution of forest cover change. The forest cover in North and Northeast China changed dramatically from 1990 to 2005, but the changes in Meng-Xin and on the Loess Plateau were not as extensive. The afforestation and reforestation projects made great strides toward increasing forest cover, whereas forest fires, forest harvesting and deforestation caused by urban and farm-land expansion led to decreases in forest cover. The annual average temperature and precipitation had clearly changed, and increased forest cover could slow down the rate of climate change to some extent in this region. Proper planning and implementation of afforestation and reforestation projects were essential to improving the-natural conditions in the TNSFR. Information about the actual forest cover changes would help in the design of appropriate forestry policies and sustainable forest management strategies.