The Combustibility On Major Forest Types Of Beijing Ming Dynasty Tombs Tree Farm

This article select three representative forest type in Beijing Ming Dynasty Tombs Tree Farm as the research object,respectively is:Needle leaf mixed forest,coniferous forest and coniferous mixed forest,choose ten sample from each forest type.This study involved 15 factors,divided into three types:site factor,stand factors,and of fuel physical and chemical properties.Study the correlation among the factors,then ranked the combustibility of different factors,and using analytic hierarchy process(ahp)to divide the combustibility of different forest types based on the above content.By the methods of field investigation,we got a sample to each site factors and related stand factor.Through the indoor experiment method we obtain the data of moisture content,calorific value and ash content factors.Tree volume of each forest finally calculated by accumulation of every tree volume through individual tree volume calculated by experiment form number method.Using R language to make a multivariate correlation analysis for stand 15 factors and make a clustering analysis for forest combustibility.The results showed that:Based on the multiple correlation analysis of 15 factors,we get the following high correlation factor relations:EW-SN(r=0.958,P=0.958),the average tree height-average living under branch height(r=0.905,P=0.905),the average tree height-die under branch height(r=0.893,P=0.893),the average diameter at breast height-live under branch height(r=0.877,P=0.877),the average death under branch height-EW(r=0.818,P=0.818),the average tree height-SN(r=0.899,P=0.899),the average tree height-EW(r=0.845,P=0.845),the average diameter at breast height-forest volume(r=0.862,P=0.862)and forest volume-stand upper withered leaves calorific value(r=0.849,P=0.849),and so on.In combustibility analysis,using analytic hierarchy process(ahp)to divide the combustibility of different forest types,divided them into three categories,classification results as follows:the first category:coniferous forest;The second category:coniferous mixed forest;Third class:Needle leaf mixed forest and coniferous forest.Based on the above research results,we can get the following conclusion from the forest combustibility analysis:the first kind of forest type:coniferous forest,in this study has most surface of the shrub and herb and litter layer fuel loads are least and its also lowest of calorific value,forests branche high is maximum,the forest fuel mainly in crown canopy.Surface fire relative are less;The second type of forest is coniferous mixed forest,it has small mean DBH in this study,but the surface of the shrub and herb and litter layer fuel loads and calorific value is the large,its forests branches high between class 2 and class 3 In Pinus tabulaeformis forest,shrubs can achieve the minimum dead branches high and the slope is small.The class stand easily has a surface fire,fire may spread to the canopy layer,fire spread speed is slow in the surface,and the spread of the fire in the forest canopy not serious like third class.;The third class stand is Needle leaf mixed forest and coniferous forest.It's mean DBH and forests branches high are maximum,But layer fuel loads is minimum,make the class stand fire is relatively difficult to occur.Forest combustion has three basic elements,among them,the fuel compared with other two elements are more likely to control management.Shisanling forest farm forest fire extremely easily,because of its climate and vegetation.Study of forest fuel and combustion have a big meaning.