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确定野火空间分布区格局的影响因素,对野火的预测、火险区划具有重要的意义,同时也为制定合理的野火管理措施提供科学依据。以中国2006—2011年野火发生面积和次数作为因变量,选取了5个影响因素,利用增强回归树(boosted regression tree,BRT)方法分析了影响野火空间分布格局的主要因素。结果表明:影响中国野火过火面积空间分布的因素从大到小依次是海拔(36.92%)、年平均气温(27.85%)、年平均降雨量(13.17%)、人口密度(13.00%)和植被类型(9.07%),总体来说,气候因子和海拔的差异决定了研究区过火面积的空间分布格局;影响中国野火火烧次数空间分布的因素从大到小依次是人口密度(27.44%)、海拔(25.97%)、植被类型(22.84%)、年平均气温(18.98%)和年平均降雨量(4.77%),可以看出,人类活动、地形和可燃物共同影响火烧次数的空间分布格局。建议在制定全国火险区划时,除了气候和植被因素外,还应该重点考虑地形,特别是海拔的影响;并且加强野外用火管理,开展可燃物的处理以减少野火的发生。
Determining the influencing factors of the distribution pattern of wildfire space is of great significance to the prediction of wildfire and the division of fire risk, and also provides a scientific basis for formulating reasonable wildfire management measures. Taking the area and frequency of wildfire occurrences in China from 2006 to 2011 as the dependent variable, five influencing factors were selected and the main factors influencing the spatial distribution of wildfire were analyzed using the boosted regression tree (BRT) method. The results showed that the factors influencing the spatial distribution of overfire area in China were: elevation (36.92%), annual mean temperature (27.85%), annual average rainfall (13.17%), population density (9.07%). Generally speaking, the difference of climatic factors and altitude determines the spatial distribution pattern of over-fire area in the study area. The factors influencing the spatial distribution of the number of wildfires in China are population density (27.44%), elevation 25.97%), vegetation type (22.84%), annual average temperature (18.98%) and annual average rainfall (4.77%). It can be seen that the spatial distribution patterns of human activities, terrain and combustibles together affect the number of fires. It is suggested that in addition to the factors of climate and vegetation, the planning of the national fire zoning should focus on the topography, especially on the impact of altitude. Fire control in the field should be strengthened to reduce the incidence of wildfire.