Evaluation Of Fire Resistance Of Main Fire-proof Tree Species In Hunan Province

The security of forest resources determines the stability of forest ecosystem and human living environment,and forest fire is an important factor to the destruction of forest,which changes the natural change trend of forest ecosystem and forest plant community.The study of fire resistance of fire-resistant-tree-species is of great value and significance for the establishment of fire resistant forest belt,economic development and ecological stability.In May 2019,we chose 6 kinds of typical subtropical broad-leaved fire-resistant tree species(Myrica rubra,Schima superba,Symplocos sumuntia,Machilus pingii,Castanopsis eyrei,Quercus glauca)as the research object in Zhuzhou city,Hunan Province.This study explored the influence of different age groups(young forest,middle-aged forest,mature forest)and organs(leaves,branches,leather)of the six plant at moisture content and thermal radiation characteristics,ignition point,heat value,crude ash,crude fiber of plants and the biological characteristics.Uni-variate analysis of variance,Fisher LSD test,principal component analysis and cluster analysis were used to explore the significant differences in fire resistance between different organs and different age of the same tree species(P<0.05)and the comprehensive ranking and cluster of fire resistance of tree species.The results showed that,(1)Compared with branches and bark,leaves have higher moisture content(53.7%),higher crude ash content(4.5%)and lower crude fiber content(23.9%);(2)With the growth of the trees,the fire resistance of the trees decreased first and then increased.And the same tree species showed the lowest moisture content,crude ash and crude fiber content in the middle-age forest stage.The leaf thickness,bark thickness and crude ash content of tree species in mature forest stage were large;(3)The comprehensive fire resistance of different organs was significantly different among different species(P<0.05).The fire resistance of leaves was shown as M.pingii>C.eyrei>S.sumuntia>M rubra>S.superba>Q.glauca.The comprehensive fire resistance of branches of different tree species was the strongest in M.pingii and C.eyrei,followed by M.rubra and S.superba.The bark of different tree species showed strong fire resistance of S.superba and C.eyrei.The bark showed that S.superba and C.eyrei had strong fire resistance,and the weakest fire resistance were M.pingii and Q.glauca;(4)There was a negative correlation between moisture content,crude ash and bark thickness,residual mass rate of bark,calorific value and crude ash,crude fiber content and leaf thickness.There was a significant positive correlation between the moisture content and the burning point,the residual mass ratio and thickness of bark.(5)Finally,the comprehensive scores of fire resistance performance of different species are obviously different.Schima superba(1.033)and M.rubra(0.526)were the most fire-resistant among the six tree species,while M.pingii(-0.405)and Q.glauca(-1.151)were the least fire-resistant.Therefore,S.superba and M.rubra are the preferred tree species in the southern fire forest belt.