大兴安岭呼中林区地表死可燃物含水量及其环境梯度分析

Ground surface dead fuel moisture content in Huzhong forest area of Great Xing'an Mountains and its environmental gradient analysis

森林地表死可燃物含水量与林火行为密切相关,理解森林地表死可燃物含水量及其与环境因子之间的关系对于林火管理有重要意义。本文对大兴安岭呼中林区的不同植被类型内的地表死可燃物含水量,依据1h、10h和100h分类标准进行了对比,结果表明:杨桦林和钻天柳林等2种阔叶林地表死可燃物含水量最高,而其他植被类型比阔叶林内地表死可燃物含水量低,且之间无显著性差异;对兴安落叶松不同林型内的地表死可燃物含水量进行比较,发现越桔兴安落叶松林内地表死可燃物含水量最高,其他林型比越桔兴安落叶松林低,且之间没有显著性差异。此外,利用除趋势典范对应分析对地表死可燃物含水量的环境梯度进行分析。结果表明:第1排序轴反映了坡位与海拔梯度,即热量因素,沿着第1轴从左到右海拔和坡位逐渐降低;第2轴反映了坡向和林分密度梯度,即水分因素。总体来说,坡位与海拔是影响森林地表死可燃物含水量的主要环境因子,二者综合作用表达了该地区森林地表死可燃物含水量的空间生态梯度。

Ground surface dead fuel moisture content in forests is closely related to forest fires. To understand this moisture content and its relationship with environmental factors is of great significance in wildfire management. In this paper, the ground surface dead fuel moisture content in different forest types in Huzhong area of Great Xing＇ an Mountains was investigated, according to the classification standard of 1, 10, and 100 h. The results showed that Betala platyphlla - Populus davidiana forest and Chosenia arbutifolia forest had higher dead fuel moisture contents than the other forest types, but no distinct difference was observed in the other forest types. Among different Larix gmelinii forest types, Vaccinium vitis-idaea - Larix gmelinii forest had a higher dead fuel moisture content than the rest Larix gmelinii forest types, but there was no obvious difference as well. The detrended canonical correspondence analysis （DCCA） on the environmental gradient of ground surface dead fuel moisture content indicated that the first axis reflected the spatial gradients of altitude and topographic position, i. e. , temperature condition, while the