A Comparison of Forest Cover Maps in China in 2010 from Multi-source: Landsat, PALSAR, MCD12Q1, FAO FRA, and National Forestry Inventory

Abstract:

Forests and their changes are quite important to global carbon cycle, biodiversity and ecological services. Some uncertainties about forest cover maps still exist in China, so an accurate and updated forest cover distribution map is necessary as a baseline for carbon cycle estimation, especially at a fine spatial resolution. In this study, we developed a decision tree classification algorithm to identify forest and non-forest land cover, based on the signature analysis of 50 m ALOS PLASAR backscatter data in 2010 for a few land cover types. We used MODIS-based NDVI dataset in 2010 (MOD13Q1) to generate a map of annual maximum NDVI and used it to mask out built-up lands, barren lands, and sparsely vegetated lands. We applied the PALSAR-based algorithm and produced a forest cover map in China in 2010. Several comparisons in forest area and spatial distribution between the resultant forest map with other forest maps were carried out. The results show that the total forest area in China from the PALSAR-based forest map in 2010 is close to those of JAXA, FAO FRA, and National Forestry Inventory, and there are good linear relationships between the PALSAR-based forest map with the JAXA, MCD12Q1, and NLCD-China forest areas at province and county scales. All the forest maps have similar forest/non-forest distribution, but our PALSAR-based forest map recognizes well the agro-forests. The results of this study provide a baseline map of forest cover in China in 2010, which can be used for the studies of forest disturbance, carbon cycle, and ecological restoration projects in China.