| Forest fire is a kind of forestry disaster which has largest and most widely impact to social economic. The natural environment for human survival and ecological balance is been damaged due to the forest resources by forest fire. Forest fire division not only can predict and forecast the forest fire, but also has most important significance to reduce injuries and economic losses cause of forest fire.This thesis base on the research status and development trend of the comprehensive analysis of domestic and international forest fire zone, taking system science, fire science and information science theory as a guide, using geographic information system, computer technology and mathematical methods. Taking county (District) as the basic unit of division, after the full investigation and data collection of forest fire danger division related, the Changzhutan each county (District) forest fire was been divided. The detailed research work and results are as follows:(1) The establishment of evaluation index system of fire risk zoning. There are numerous forest fire factors. And according to the industrial standard of national grade of the forest fire division(LY/T 1063-2008), six factors are included:the combustion level of tree species, population density, the monthly average precipitation, temperature, and wind speed in fire season, and the density of road network. Fire danger grade can be divided into three levels, respectively, the low, medium and high fire danger. Each forest fire danger factor needs to be divided into three grades. Each factor according to the industry standard in the forest fire in the distance, all factors constitute a zoning index system of forest fire(2) To determine the weights of the forest fire. The standard data is normalized. The different grades weights of every factor of forest fire danger are calculated and a weight matrix will be formed with these weights.(3) The Changzhutan county (District) forest fire region. Taking the Changzhutan cities group as example, the data are first sorted out by using the theory of variable fuzzy sets to calculate the characteristic value of the fire danger grades of each county. Then, the forest fire danger grades are determined by the characteristic value. At last, compare with the actual fire danger rating. There are eight low fire danger areas (Furong district, Tianxin district, Kaifu district, Hetang district, Lusong district, Shifeng district, Tianyuan district and Yuhu district), seven middle fire danger areas (Yuhua district, Wangcheng district, Yuetang district, Zhuzhou country, Chaling country and Shaoshan city), and eight high fire danger areas (Yuelu district, Changsha country, Liuyang lcity, Ningxiang country, You country, Liling country, Xiangtan country and Xiangxiang city).(4) results contrast analysis. This result has 82.6% consistent with the standard results (The results calculated in accordance with national standards). In conclusion, fire danger grade is related to each factor and each factor also constraints mutually. By using the theory of variable fuzzy sets, the mutual influence between the factors can be considered less, thus reaching a much scientific and reasonable conclusion.Forest fire danger division will be influenced by various aspects of social environment. Therefore, it is a complicated system engineer and also a long-term and arduous work. As the ecological environment construction attracts more and more attention, along with stricter and stricter demand for forest fire prevention engineer, and more and more developed science and technology, the demand for the degree of accuracy and precision to forest fire danger division will become higher and higher. In the present study, due to the limitations of the data collected, consideration is not comprehensive enough, should also consider more forest fire danger factors, and establish a more perfect fire zoning index system. |
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