林火因子对大兴安岭森林植被演替的影响

森林火灾因火烧强度、频率及大小等方面的不同,形成了许多不同的火烧迹地,对火后演替有重要的影响 不同火烧程度的迹地上残存的活植被繁殖体的多度及其空间分布等方面有很大的不同,且直接影响火后植被的初始演替格局及动态 相对于中轻度火烧迹地而言,重度火烧迹地由于残留的活植被繁殖体很少等因素,极大地增加了演替的不确定性 火烧频率随着林分位置、类型、林龄以及林分的疏密度等方面的不同而有很大的差异,火烧频率的增加会阻碍植被向森林演替,甚至导致森林向灌木草本演替 一般面积大的火烧迹地相对于中小火烧迹地而言,火后森林物种的丰富度低,灌木草本的盖度低,外来物种多 火烧程度、频度和大小等林火因子往往相互作用共同影响火后植被,增加了演替的复杂性及其不可预测性

Influence of Forest Fire on Vegetational Succession in Daxinganling

Forest fire,varying in intensity,frequency and size,leads to some different burned areas and influences succession accordingly. The abundance and spatial arrangement of such biological legacies can have substantial influences on successional pattern and dynamics. Compared with moderately or lightly burned areas,severely burned areas with fewer biological legacies increase uncertainty of succession. Fire frequency varies in stand site,type,age,and cover.An increase in the frequency can make the potential conversion from forest to shrubs or herbs. Compared with moderate or small patches,large patches have lower species richness,lower cover shrubs,and greater opportunistic species. The interaction of fire severity,frequency and size,influences post-fire vegetation and increases the complexity and unpredictability of succession.