Tempo-spatial variations of net primary productivity in hilly terrain of southern China

With the increased study on the terrestrial carbon cycle, the function of vegetation has become focused on more widely. Net primary productivity (NPP) , as one of the characters of vegetation, plays an important role in global change and carbon cycle research in the terrestrial ecosystem. The study on NPP and its tempo-spatial variation in the hilly terrain of southern China would be helpful to understand the growth condition of vegetation and to evaluate the ecological effects of large-scale vegetation construction. In this paper, Carnegie-Ames-Stanford Approach (CASA), a carbon processes-based model based on remotely sensed data, was applied to estimate the terrestrial NPP in hilly terrain of southern China. Monthly MODIS NDVI images, monthly mean temperature, precipitation, solar radiation, vegetation type between 2000 and 2010 were collected for the simulation. The change of land cover was an important factor for vegetation spatial variation. Especially, the implementation of large-scale vegetation constructions by returning farmland to forests or grassland has increased rapidly the forest leading to a large rise in NPP.