Based on 135 actual data by the investigation of 45 pl ots and 225 sample plots in Qinling to the maximum crown density (D) of easi ly burning layers, to the amount of the surface burning material(W) and to t he absolute water-content ratio (μ) in the surface burning material, and b y means of dissimilarity analysis method, 45 plots we have investigated can be o bviously divided into 6 groups. According to differences among these groups, for est potential fire behavior in Qinling mountains crown fires can be divided into strong crown fire type, weak crown fire type and no crown fire type based on th e maximum crow density of easily burning layers, separated by indices D 0.11 kg/m3 and 0.37kg/m3 respectively; the intensity of surface fire can be d etermined by the μ and W factors and be divided into 3 classes, the str ong surface fire and the medium surface fire, separated by indices W 1.40k g/m2 and indices μ 40% respectively. According to those, all potential fi re behaviors of forest in Qinling can be divided into 9 growps, the strong crown fire and strong surface fire(D>0.37kg/m3,W≥1.40kg/m2, μ<4 0%), the strong crown fire and medium surface fire (D>0.37kg/m3, W≥ 1.40kg/m2, μ≥40% or W<1.40kg/m2, μ<40%), the strong crown fire and weak surface fire(D>0.37kg/m3,W<1.40kg/m2,μ≥40%) , the weak crown fire(0.11kg/m3≤D≤0.37kg/m3) and strong surface fi re, the weak crown fire and medium surface fire, the weak crown fire and weak su rface fire, no crown fire(D<0.11kg/m3) and strong surface fire, no crown fire and medium surface, and no crown fire and weak surface fire respectively.%根据秦岭林区45块标准地和225个样方的冠层易燃 物最大密度(D)、地表可燃物载量(W)及地表可燃物绝对含水率(μ)3个实测值的135个数 据，运用Dissimilarity analysis计算认为，调查的45块标准地明显地可聚为6类。据类间 差异性将秦岭森林潜在树冠火行为分为强度树冠火、弱度树冠火和无树冠火3种类型，划分 依据为冠层易燃物最大密度，区分指标分别为0.11kg/m3和0.37kg/m3；地表火强 度划分应用μ和W双因素判断法，并将其划分为强度地表火、中度地表火和弱度地表火3 种类型，其区分指标分别为地表可燃物载量1.40kg/m2和地表可燃物绝对含水率40%。 据此，秦岭林区潜在火行为共划分为9种类型，分别为强度树冠火强度地表火类型(D>0 .37kg/m3，W≥1.40kg/m2，μ<40%)、强度树冠火中度地表火类型(D >0.37kg/m3，W≥1.40kg/m2，μ≥40%或W<1.40kg/m2,μ <40%)、强度树冠火弱度地表火类型(D>0.37kg/m3，W<1.40kg/m2， μ≥40%)、弱度树冠火(0.11kg/m3≤D≤0.37kg/m3)强度地表火类型、弱 度树冠火中度地表火类型、弱度树冠火弱度地表火类型、无树冠火(D<0.11kg/m3) 强度地表火类型、无树冠火中度地表火类型和无树冠火弱度地表火类型。
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