A Study of Dynamic Variations for Vegetation Cover and the Damage of Vegetation in the Area of the Earthquake——Taking Lushan County for Example

In this paper,based on Landsat TM and ETM image data,the model of damage of vegetation is established to evaluate the level of the vegetation damage, and the improved model of dimidiate pixel method is used to estimate the Fraction Cover(FC) of the study area. A description is given of the changes of FC and analysis is made of characteristics of its spatial distribution. The results have shown that:① from year 2009 to 2013, the average FC of LuShan reduced from 75.47% to 75.47% ②Vegetation of higher coverage had the largest area in the two periods, accounting for about 36% of the total area. A substantial reduction of area of highest rank of FC occurred in 2009, which mainly changed into middle FC in 2013. ③The area of mild decrease and stable area were dominant in the change of FC from 2009 to 2013, which accounted for 75.66% of the total area and the area of obvious reduction accounted for 9.68%. ④FC changed along with the elevation, slope and aspect. ⑤ The model of vegetation damage was established on basis of NDVI to estimate the vegetation damaged by the earthquake. Most of the severely damaged area was due to the landslide and collapse caused by the earthquake. By studying the damage of vegetation and dynamic variations for Vegetation Fraction Cover,the destruction of the vegetation by the earthquake disaster was revealed in order to provide better decision-making for the ecological restoration.