The effect of large-scale conservation programs on the vegetative development of China's Loess Plateau

The Natural Forest Conservation Program (NFCP) in 1998 and the Grain for Green Program (GfGP) in 1999 were launched by the Chinese government to mitigate the degraded vegetation condition of China. In this study, we applied MODIS time series data to analyze the impacts of land cover change as a result of vegetation conservation programs on vegetation dynamics in the Chinese Loess Plateau from 2001 through 2009. We applied the seasonal Mann-Kendall trend test to the Normalized Difference Vegetation Index (NDVI) time series calculated based on the Nadir BRDF-Adjusted Reflectance data at 500 m (MCD43A4). In addition, to identify the changes at multiple scales, we also applied the seasonal Mann-Kendall trend test to the global Albedo product and NDVI calculated based on the Nadir BRDF-Adjusted Reflectance data at 0.05 deg CMG (MCD43C3 and MCD43C4). To understand the effect of grazing changes in grasslands we selected data from three separate Landsat tiles and two different years and calculated both NDVI and the Enhanced Vegetation Index (EVI). We show that the observed changes are the most widespread when observed with NDVI data at 0.05 resolution and the least widespread when observed with albedo data. The data at the higher spatial resolution of 500 m revealed that the rainfed croplands are changing (i.e., 69% exhibiting change) while the irrigated croplands remain stable (just 11% reveal change). This change appears consistent with the effect of GfGP. Both the counties with increased and degreased grazing reveal an increase in 500 m NDVI data. Thus, grazing analyses are more complicated for these areas