Dynamic monitoring of vegetation coverage in the three-north shelter forest program by the analysis of multiyear NDVI data

GIMMS/NDVI was selected as the data source in this paper. The spatio-temporal variation of the vegetation cover of the study area was monitored by employ NDVI average, retrieval of vegetation cover and linear regression trend analysis methods. The results show that: NDVI vegetation of the study area has an entirely rising trend with the rate of 0.007/10a. Especially the growth of Sandy Area, Northeast and north China plain were obvious, but Northwest Desert Area has a subtle declining tendency. Vegetation coverage areas of the study area have been increased by almost (higher and lower) 2.64% and 10.86% of the total area, while reduced by about (higher and lower) 0.38% and 4.08%. The vegetation coverage of four construction regions has been improved in different degree, Gully region of loess plateau was the fastest and vegetation coverage improved 9.66%.