| Tree species type,age structure and ecological change process in forest ecosystem are affected by various factors,and forest fire plays an indispensable role.The occurrence and spread of forest fire cannot be separated from meteorological,terrain and loads.Among them,fuel is the basic condition of forest fire combustion,and understanding its distribution characteristics and potential fire behavior is the fundamental way to solve the problem of forest fire safety.This study takes typical forest fuels in southern Jiangxi as the research object,firstly analyzes the fuel loads and its direct and indirect relationship with environmental factors,and then sets up a standard fuel model by cluster analysis with key parameters of fuel as variables,and then uses FARSITE model to evaluate the spatial distribution of the fuel model’s fire behavior.The main conclusions are as follows:（1）The surface fuel loads of the main vegetation types in southern Jiangxi were significantly different.The fuel loads of Masson Pine forest and coniferous broad-leaved mixed forest（P.massoniana-C.lanceolata-Schima superba）were significantly higher than those of other vegetation types.At 1h time-lag fuels,the highest fuel load was found in coniferous and broad-leaved mixed forest(mean 516.3kg·hm-2),while the lowest was found in Phyllobamboo forest(211.3 kg·hm-2);at 10h time-lag fuels,the highest was the coniferous broad-leaved mixed forest(516.3kg·hm-2),and the lowest was the phyllobamboo forest(353.24 kg·hm-2);at 100h time-lag fuels,the highest was the coniferous broad-leaved mixed forest(737.77kg·hm-2),and the lowest was the phyllobamboo forest(469.71 kg·hm-2).The influencing coefficient of environmental factors for 1h time-lag fuels were ranked as:slope（Influence coefficient:0.40）>crown height（0.07）>tree species（-0.03）>canopy closure（0.01）;for the 10h time-lag fuels,the environmental factors were ranked as:diameter at breast height（0.15）>tree species（-0.09）>aspect（-0.08）>canopy closure（-0.06）;for the 100h time-lag fuels,the environmental factors were ranked as:aspect（0.25）>diameter at breast height（0.19）>canopy closure（-0.08）>tree species（0.02）;The influencing coefficient of environmental factors for the total fuels were ranked as:slope（0.22）>tree species（-0.04）,canopy closure（-0.04）>crown height（-0.01）.（2）The results show that four standard fuel models can be established in southern Jiangxi,and the representative vegetation types are Phyllostachys heterocycla forest（model FL-I）,Pinus massoniana forest（model FL-II）,coniferous mixed forest（Pinus massoniana-Cunninghamia lanceolata）,broad-leaved and coniferous mixed forest（P.massoniana-C.lanceolata-Schima superba）and C.lanceolata forest（model FL-III）and Schima superba forest,broadleaf mixed forest（S.superba-Liquidambar formosana）（model FL-IV）.The prediction results of the fire behavior of different fuels and the surface and vertical structure characteristics of the four standard fuel models can provide help for forest fire management.（3）The forest fire behavior in southern Jiangxi is mainly distributed in ClassⅢ（strong fire risk）and ClassⅣ（strongest fire risk）under the two forest fire risk levels,which are easy to occur and easy to occur according to the historical fire conditions.The spatial distribution characteristics of fire behavior grade are obvious and show the characteristics of continuity.The high-intensity forest fire behavior was mainly distributed on the sunny steep slope with the fuel models FL-Ⅲand FL-Ⅳ,and was close to roads and residential areas.In this study,seven typical forest types in southern Jiangxi were divided into four types of fuel models and a set of standard parameters were summarized to provide a theoretical basis for management departments to manage forest fire prevention. |
