Study On Characteristics Of Surface Fuel Load And Fire Behavior Of Three Conifer Species In Eastern Liaoning Province

Pinus tabulaeformis,Pinus sylvestris,and Larix kaempferi(Lamb.)Carr.are the three main coniferous species in Liaoning Province.These three conifers are both important timber tree species,and which have great economic value,this three conifer are both important timber tree species and main afforestation species in this region.The systematic study of the surface combustibles and fire behavior of these three conifers is of great significance for further strengthening the forest fire monitoring and prevention.Focused on the Pinus tabulaeformis and Pinus sylvestris,Larix kaempferi(Lamb.)Carr.,this study measured the fuel load,moisture content and calculated fire behavior for each spices.The main findings are presented as follows:(1)The surface fuel load and fuel load equation were calculated and eseablished by random swapling method and regression analysis method,respectively.The results showed that the average of surface combustible materials of Pinus tabulaeformis,Pinus sylvestris,and Larix kaempferi(Lamb.)Carr.is 10.70 t/hm2,11.24 t/hm2 and 18.48 t/hm2,respectively.The three combustible models of these three conifers were established by forest factor.Which were y =8.177+0.098 x1-2.083 x2-0.839 x3,y =7.461+0.076 x1 +0.518 x3+0.541 x4,y =11.899+0.123 Xi+0.875 x3+0.998 x4 for Pinus tabulaeformis,Pinus sylvestris,and Larix kaempferi(Lamb.)Carr.,respectively.The regression of each model is significant,r is 0.924?0.848?0.884,repectively.(2)Water content at equilibrium and time lag were measured by indoor timing weighing method and timing method,respectively.Subsquently,the dynamic equation of water content were eseabhicd by regression analysis.The results showed,when the relative humidity was 40%,the equilibrium moisture content of the surface combustible material of Pinus tabulaeformis,Pinus sylvestris and Larix kaempferi(Lamb.)Carr.was 8.98%,8.21%and 6.57%,respectively,and the lag time was 11.60 h,14.00 h,11.20 h,respectively.When the relative humidity was 50%,the equilibrium moisture content of the surface combustible material of Pinus tabulaeformis,Pinus sylvestris and Larix kaempferi(Lamb.)Carr.was 9.32%,10.81%and 9.39%,respectively,and the lag time was 16.00 h,16.80 h,13.20 h,respectively.When the relative humidity was 60%,the equilibrium moisture content of the surface combustible material of Pinus tabulaeformis,Pinus sylvestris and Larix kaempferi(Lamb.)Carr.was 10.13%,13.70%and 12.41%,respectively,and the lags were 19.60 h,24.00 h and 20.40 h,respectively.The relation equation between the equilibrium moisture content and the relative humidity of the surface combustible of Pinus tabulaeformis,Pinus sylvestris and Larix kaempferi(Lamb.)Carr.was y=0.399x0.793,y=0.177x1.042,y=0.021x1.557,r is 0.985?0.967?0.988.The combustible equilibrium moisture content increased with the increase of humidity.The relation equations between the lattice and the relative humidity of Pinus tabulaeformis,Pinus sylvestris and Larix kaempferi(Lamb.)Carr.was y=19.73lnx-61.182,y=19.2681nx-55.915,y=19.136lnx-59.267,respectively,r is 0.962?0.904?0.982.With the increase of relative humidity,the combustible material increases.(3)Set the temperature as 5?,10?,15?,20?,25?,5 gradients,and set the moisture content as 10%,15%,20%,25%,30%.The results showed that with the increased of tempreture,flame propagation speed,flame height and flame temperature of the three spices showed an increasing trend.By contrase,the flame spread speed,flame height and flame temperature decreased with the increase of water content.