The vegetation coverage dynamics due to geohazards after the 2008 earthquake in Wenchuan

A catastrophic earthquake with a Richter magnitude of 8.0 occurred at Wenchuan area of Sichuan province on May 12, 2008. The earthquake destroyed forests and natural vegetation. As a result, it is necessary to assess the vegetation recovery rate for decision making and policy planning in earthquake region. In this paper, we calculated the vegetation index in 2001, 2009, 2010, 2013 employing RS methods. According to the analysis of mean change trend of vegetation index, the vegetation index in 2009 was clear lower than that in 2001, the main reason is that the vegetation loss caused by the 2008 Wenchuan earthquake; the vegetation index mean in 2010 was lower than that in 2009, and image imaging at different times, vegetation index mean reduction is caused by seasonal changes; the vegetation index mean in 2013 is slightly higher than that in 2010, it showed that vegetation coverage began to be slowly recovering after the earthquake. According to the standard deviation of vegetation index, vegetation index has the smallest standard deviation in 2001, this showed it has a good homogeneous distribution before the earthquake; vegetation index has the largest standard deviation in 2009, indicates poor homogeneity after the earthquake; from 2009 to 2010 and to 2013, the standard deviation of vegetation index becomes smaller year by year, means that the homogeneity becomes better and vegetation cover also slowly get better. We anticipate that these results will be helpful in decision making and policy planning for recovery and reconstruction in the earthquake-affected area.