Abstract:

Objective: In order to provide a scientific monitoring result and diagnostic basis for the temporal and spatial variation of vegetation cover in Guangxi, the change characteristics of vegetation cover and its key factors from 2006 to 2016 were explored. Method: The whole changes of vegetation cover in Guangxi were explored through trend analysis method based on MOD13Q1. The relationships between vegetation cover change and temperature and precipitation were explored through regression analysis method. The effects of human activities on the vegetation cover change reflected by MODIS land cover data were analyzed by using difference method between remote sensing images in different phases.Result: Guangxi's vegetation coverage was increasing with fluctuation during the past 11 years. The NDVI has the lowest vitality in February and March, while the highest was in September. The area of improved vegetation was much larger than that of degraded ones. The largest regions of improvement were Hechi, Baise, southeast of Nanning and east of Guilin, and the largest regions of degradation were Chongzuo, middle of Baise, west of Nanning and middle of Guilin. Beihai city, the most seriously degraded area, has a 28.9% degrading area. The types of Guangxi's vegetation coverage have changed a lot. Forestry area increased significantly, while agricultural area decreased significantly. Objective: Temperature and precipitation are positively correlated with vegetation cover, the positive correlation is more significant on the monthly scale than that on the annual scale. The effects of precipitation on vegetation were more significant than those of temperature. Human activities reflected by MODIS land cover data indicates that the significant increase in forestry area is the main reason for the increase of Guangxi's NDVI.

Key words: vegetation cover, normalized difference vegetation index(NDVI), climate factors, human activities, Guangxi