疏伐对北京西山林场刺槐林可燃物特征及碳储量影响研究

Effect of thinning on fuel characteristics and carbon stock of Robinia pseudoacacia forest in Beijing Xishan Forest Farm

研究选取北京西山林场刺槐林(Robinia pseudoacacia)为研究对象,通过对照组CK和处理组L、M和H(疏伐强度分别为0%,15%,35%,50%)四种处理,对疏伐后刺槐林可燃物进行调查,对不同强度疏伐刺槐林林地上部分碳储量进行计算,并利用Behave Plus林火模型对地表火行为指标进行计算,探讨不同疏伐强度对刺槐林可燃物、碳储量以及潜在火行为的影响。结果表明,(1)不同疏伐强度的刺槐林的可燃物分布中,均以0—2 m层可燃物负荷量为最大,分别为1.29 kg·m^(–2),1.40 kg·m^(–2),1.57 kg·m^(–2),1.89 kg·m^(–2),呈现出可燃物负荷量随疏伐强度加大而增加,即,H>M>L>CK;随着高度的增加,可燃物负荷量主要分布冠层在5—8 m;(2)不同强度疏伐对刺槐人工林各组分的碳储量影响显著,中度疏伐更有利于刺槐林中的碳储量积累,其碳储量值最大,为17.50 t·hm^(–2);(4)林分火蔓延速率、火线强度、火焰高度及单位面积发热量均与疏伐强度相关,疏伐后火行为指标值大幅下降,其中高强度疏伐(H)后,林火的蔓延速率,火线强度为以及火焰强度最低。研究结果可为研究地区的森林可燃物管理以及森林可持续经营提供科学依据。

The typical Robinia pseudoacacia forests under different thinning intensities(0%,15%,35%,50%)in Beijing Xianshan Forest Farm were selected.The effects of different thinning intensities on forest fuel loading,above-ground carbon stock and potential fire behaviors were studied by using field investigation,calculation and BehavePlus software.The results are as follows.(1)The maximum fuel loading of different thinning stands all distributed in the layer of 0-2 m,with the value 1.29 kg·m–2,1.40 kg·m–2,1.57 kg·m–2,1.89 kg·m–2,respectively.Along with the increase of the vertical height,the fuel load was mainly distributed in the layer from 5 m to 9 m.(2)The stand carbon stock was significantly affected by thinning intensity,and the moderate(M)thinning intensity stand had the highest carbon stock,with the value 17.50 t·hm–2.(4)Forest fire velocity of propagation,heat per unit area,fire line intensity,and flame length were affected by thinning intensity,and the potential fire behaviors values decreased sharply after thinning treatment,and the high intensity thinning(H)had the lowest fire behavior value.The above results can provide a scientific basis for the forest fuel management and sustainable forest management in the studied area.