Da Xing’an Mountains Vegetation Index Variability And Impact Factor Analysis

With industrial development and the progress of science technology, human material life is greatly improved, but it resulting in the global environmental problems is becoming more and more serious. China is in social development stage, the resulting environmental problem is increasingly serious, and it has serious influence to people’s production and life conditions yet. The most serious environmental problem is the air pollution, vegetation is an important part of the earth’s ecological system, is very sensitive to atmospheric pollution, and the ability to respond to it accordingly. So the change trend of vegetation monitoring for people to understand and manage the environment problem has very important significance. The purpose of this study is to use remote sensing technology to realize the monitoring of vegetation index change trend and analyze the influence factors of the change tendency, in order to guide the forestry authorities to carry on the scientific management of the forest, promote the growth of forest health, and alleviate the pollution of the environment, optimize the environment of the earth.The Normalized Difference Vegetation Index (NDVI) from the remote sensing data could accurately reflect the condition of vegetation growing, and it facilitated the long-term monitoring of vegetation at regional scale. This study monitored and analyzed the yearly changes of the NDVI based on the MODIS/NDVI monthly data of Da Xing’an Mountains region from 2000 to 2009. Trend analysis, hypothesis testing and correlation analysis were used to investigate the effects of various factors on the changes of the NDVI value. The results showed that the annual average NDVI ranged from 0.455-0.509, with the average NDVI of 0.477 from 2000 to 2009. No regular trend was observed for the annual variations. In addition, the effects of the forest fire, temperature and precipitation on the NDVI were analyzed. It is found that the general forest fires had no significant impact on the growth of NDVI value, while the serious forest fires and the major forest fires with the burned area smaller than 10000 hm2 promoted the growth of the NDVI value; the major forest fires with the burned area larger than 10000 hm2 forest fires significantly reduced the NDVI value. The temperature between 10℃ and 25℃ promoted the increase of the NDVI value, no significant impact was observed on the NDVI changes when the temperature was below 5℃. The monthly precipitation less than 75 mm promoted the increase of the NDVI value, no obvious impacts were found on the NDVI changes when the monthly precipitation was more than 100 mm.