Temporal And Spatial Patterns And Driving Forces Of Fire In Great Xing'an Mountains

Forest fires are the main natural disturbances in the Great Xing'an Mountains.The occurrence of forest fires affects the structure and function of the ecosystems in the Great Xing'an Mountains.Forest fire disturbances have changed the succession trajectory of forest ecosystems and are one of the important driving forces for reshaping forest ecological landscapes.The size of forest fire intensity directly affects the succession and restoration of forest vegetation.The implementation of the 1998 Natural Forest Protection Project(NFPP)has greatly changed the interference of human activities on forests,but the consequences of such disturbances are still unknown.At the same time,with the intensification of climate change in recent decades,the frequent occurrence of extreme weather has made the forest ecosystem more fragile and sensitive.The human disturbance(NFPP)and the climate change have profoundly affected the Great Xing'an Mountains,which is reflected in the forest fire.The change in intensity.As an emerging technology,remote sensing technology plays an important role in the fields of fire danger zone division,overfire zone mapping,post-fire vegetation monitoring,etc.This study is based on the landsat5 TM data of the Great Xing'an Mountains obtained from the landsat series of remote sensing satellit es,1988-2009.The information on the ground fire in 1988-2009 obtained from the fire prevention office of Great Xing'an Mountains District,draws the time-space pattern of the fire in 1988-2009 in Great Xing'an Mountains,and extracts the NBR index and dNBR index of the fire data.According to the most suitable d NBR range of Great Xing'an Mountains area(0.265-0.665)Determine the forest fire intensity in the area,compare the forest fire intensity data with the regional meteorological data of Great Xing'an Mountains,and conclude that:1.During the period of 1988-2009,the number of fires and the area of fires in the Great Xing'an Mountains showed a significant upward trend.Before the NFPP in 1998,the fires in the Great Xing'an Mountains were dominated by low-intensity fires,and after 1998,the proportion of low-intensity fires was presented.There was a significant downward trend(P<0.05).Before 1998,the high inte nsity fire did not dominate.After 1998,the high intensity fire showed a signific ant upward trend and dominated(P<0.01).2.From the perspective of spatial distribution pattern,before the implementa tion of the Tianbao project,the distribution of forest fires in the Great Xing'an Mountains is relatively scattered.There is no obvious law after the implementation of the NFPP.The number of fire occurrences and the area of fire in the central and southern areas have shown an obvious upward trend.Correlation analysis between meteorological data and forest fire intensity information shows that the monthly average maximum temperature and high intensity fire ratio show a significant positive correlation(P<0.05),and a significant negative correlation with low intensity fire(P<0.05);monthly mean wind speed and high intensity fire showed a significant negative correlation(P<0.05),and a significant positive correlation with low intensity fire(P<0.05).There was no significant correlation between monthly mean precipitation and forest fire intensity.The implementation of the NFPP is the main controlling factor for the change of forest fire intensity in the region from 1988 to 2009.