Spatial-Temporal Distribution And Fire Danger Area Division Of Forest Fire In Inner Mongolia Great Khingan

Inner Mongolia Great Khingan is the key state-owned forest area where forest fire occurs most frequently in north China,and the research on spatial-temporal distribution and fire danger area division of this area is of great importance to forest fire prevention of this area.With Inner Mongolia Great Khingan as the research area,this thesis collected the historical data of forest fire of this area from 1990 to 2019,meteorological data of the same period,basic geographic data and DEM data,analyzed the spatial-temporal distribution characteristics and influence factors of forest fire in the research area with statistical analysis,spatial analysis,random forest algorithm and other methods,carried out forest fire danger area division,and reached the following conclusion:(1)Forest fires occurred most frequently in the research area from 2000 to 2009,and the burned area was the largest.The burned area from 2010 to 2019 was the smallest;forest fires occurred most frequently in summer,and the burned area was the largest in spring;forest fires occurred most frequently from 10:00 to 15:00 in a day.Forest fires were concentrated in space to some extent: they were mainly concentrated in the southeast of research area from 1990 to 1999,in the north and the southeast of research area from 2000 to 2009 and in the north from 2010 to 2019,showing a trend of transferring from the southeast to the north in general;forest fires were mainly concentrated in the southeast of research area in spring,while they were scattered in summer.(2)According to the influence of meteorological factors on forest fires,temperature,precipitation and relative humidity have significant effects on forest fires;The distribution of forest fire in terms of topographic relief,slope gradient and slope direction in research area showed no significant features.There were most fire points at an elevation from 400 m to 800 m,and there were fewer fire points at an elevation above 1,000 m,so the number of fire points decreased as elevation increased.(3)Relative humidity had a greatest influence on forest fire of research area;And the forecast accuracy was higher than 86%.(4)Class IV,V forest fire danger areas were mostly concentrated in the north and the southeast of research area,accounting for 16.6% and 7.7% of the total area respectively.There were extremely high risk of forest fire,and forest fires mostly occurred in the forest areas managed by North Administration of Primitive Forest and Dayangshu Forestry Bureau;a small number of areas in the middle were class IV fire danger areas with high risk of forest fire,and forest fires mostly occurred in the forest areas managed by Keyihe Forestry Bureau and Genhe Forestry Bureau.