Comprehensive Evaluation Method Study On Forest Fire Rating Of Forest Subcompartment

Forest fire is a kind of serious natural disasters. Once forest fire break out, it is easily lose artificial control, and may cause huge economic losses. Forecasting of forest fire danger is an important part of forest fire prevention. Accurate forecasting of forest fire danger rating can provide scientific support for the forest fire prevention. The influence factors of forest fire danger are very complex. Among them, meteorological elements and the attributes of fuel are the most important factors. Forest is mostly located in mountainous area, where the terrain is complex. The meteorological elements are affected by terrain and underlying surface. Predicting the change of meteorological elements accurately, is the precondition of forest fire danger forecasting. The distribution, load and flammability of fuel and other attributes determined the difficult degree of forest fire and the extent of the harm of forest fire spread. In this paper, forest fire weather index is calculated using spatial interpolating data of meteorological elements of forest subcompartment. We put forward forest fire evaluation index based on fuel load and flammability, Proposed the comprehensive evaluating method of forest fire danger rating The main results and conclusions of this paper are:(1)we designed and built a interpolation model of air temperature in the mountainous area based on PRISM model. The PRISM model used not only the altitude and distance, but also the slope. Using different methods to interpolate daily average temperature, daily maximum temperature and daily minimum temperature. The RMSE of daily average temperature interpolation using PRISM model is lower than other methods throughout the year. Compared with other interpolation methods, the interpolation using PRISM model has a smaller rangeability, and the interpolation results is more stable. The interpolation results of the microenvironment of mountainous area temperature based on the PRISM model has high accuracy and good stability.(2)There is a strong correlation between air humidity and air temperature.In this paper,using the method of humidity calculation model,joined the humidity calculation mo dule in the temperature interpolation model. The interpolation result was verified, the c onsequence show that the absolute error of humidity interpolation is below 8%, the ave rage absolute error is 2.81%.(3)Based on the combustion test, the fuel’s flammability index was calculated using the initial ignition moisture content of it,the burning speed of it and the burning area of the it. According to the multiple regression relationship between the moisture content of fuel and meteorological elements, the forest land surface fuel moisture models of Vitex negundo L. var. heterophylla(Franch.) and Ziziphus jujuba Mill. var. spinosa(Bunge) Hu ex H. F. Chow were set up respectively based on the previous research. The relationship between fuel moisture content an fuel flammability was obtained trough the combustion test.(4) In this paper, forest fire weather rating is calculated using spatial interpolating d ata of meteorological elements of forest subcompartment. And figure out the forest fire weather rating of each forest subcompartment with ArcGIS. Established the evaluation method of forest fire danger according to the relationship of moisture content and flam mability of fuel. Now, common fire danger forecast in our country only considered the contribution degree of meteorological elements. This study provide a more reasonable method of forest fire danger forecast.