Surface Fuel Load And Influencing Factors Of Main Forest Types In Beijing Ming Tombs Forest Farm

As a material basis for the forest fires,the research on forest fuel load can effectively and accurately predict the forest fire hazard rating,and can guide the prediction of forest fire behavior before the occurrence of forest fires.Different types of stand structure had different forest fuel load.Therefore,analyzing the correlation between the surface fuel load and the impact factor of different forest types,and then based on the factors that significantly influence the fuel load,a regression model for the total surface fuel load for different forest types was established,which provided a good basis for the future formulation of forest fuel load and the prediction of potential fire behavior.The significance and correlation analysis between fuel load(lower surface fuel load,upper surface fuel load,1hr death branch fuel,10 hr death branch fuel,100 hr death branch fuel,shrub fuel load,total surface fuel load)in different types of forest and influencing factors(elevation,slope,canopy breadth,canopy cover,stand age,DBH,mean total height,live branch height,dead branch height,and surface layer thickness)were calculated by SPSS 18.0.Selecting the most significant and relevant factors in all types of forest and using the stepwise regression method to establish a multiple regression model of fuel load,the main conclusions are as follows:(1)The calculation results of fuel load in different forest types showed that the total surface fuel load of each forest type was 717.93g/m2?1234.75 g/m2,and the maximum surface fuel load was 1.72 times of the minimum load,and the difference was significant.The order of total surface fuel loads is:Pinus tabulaeformis>Acer mono>Platycladus orientalis>Cotinus coggygria.For the Cotinus coggygria forest,upper surface fuel load,1hr death branch fuel,10 hr death branch fuel are the largest.For the Platycladus orientalis forest 100 hr death branch fuel is the largest.For the Pinus tabulaeformis forest,the shrub fuel load is the largest.For the Acer mono forest lower surface fuel load is the largest.There was no significant correlation between coniferous forest and broad-leaved forest in lower surface fuel load,upper surface fuel load,1hr death branch fuel,10 hr death branch fuel,100 hr death branch fuel and total surface fuel load.Coniferous forest shrub fuel load is 5.54 times that of broad-leaved forest.(2)The results of correlation analysis showed that:For the Pinus tabulaeformis forest,the total surface fuel load was mainly affected by elevation,DBH,and surface layer thickness,1hr death branch fuel,10 hr death branch fuel was mainly affected by elevation and mean total height,shrub fuel load was mainly affected by stand age;For the Platycladus orientalis forest,the total surface fuel load was mainly affected by elevation,slope,stand age,DBH,and surface layer thickness,shrub fuel load was mainly affected by stand age and mean total height,10 hr death branch fuel was mainly affected by canopy cover.For the Acer mono forest,shrub fuel load was mainly affected by elevation and mean total height,1 hr death branch fuel was mainly affected by canopy breadth,10 hr death branch fuel was mainly affected by slope.For the Cotinus coggygria forest,shrub fuel load was mainly affected by canopy cover and DBH,1 hr death branch fuel was mainly affected by live branch height.There is no significant correlation between total surface fuel load and all factors in Acer mono forest,and Cotinus coggygria forest.For the coniferous forest,total surface fuel load was mainly affected by elevation,slope,DBH,and surface layer thickness,1 hr death branch fuel and 10 hr death branch fuel were mainly affected by canopy cover.For the broad-leaved forest,total surface fuel load was mainly affected by DBH,mean total height and surface layer thickness,1 hr death branch fuel was mainly affected by dead branch height.(3)Establishing a regression model of 6 most correlated and significant impacting factors(elevation,slope,DBH,mean total height,stand age,surface layer thickness,)with total surface fuel load by using stepwise regression method,the results are as follows:For the Platycladus orientalis forest,total surface fuel load was mainly affected by elevation,slope,DBH,stand age and surface layer thickness.For the Pinus tabulaeformis forest,total surface fuel load was mainly affected by mean total height,elevation and surface layer thickness.For the coniferous forest,total surface fuel load was mainly affected by elevation,slope,DBH,and surface layer thickness.For the broad-leaved forest,total surface fuel load was mainly affected by DBH,mean total height and surface layer thickness.For the Pinus tabulaeformis forest regression model,F=38.94,P-value=0.007,R=0.987,R2=0.975,this model has the best regression effect in statistics.