不同径级乔木主要部位灰分质量分数比较1）

采用外业调查和室内燃烧相结合的方法，分别对大兴安岭林区3种主要树种的皮、干和枝的灰分质量分数进行了测定，分析了灰分对主要树种各部位的燃烧性能的影响。结果表明：1）比较分析发现，针叶树和阔叶树的干部灰分质量分数均为最低，树枝灰分质量分数从树冠的上、中、下依次增大；2）相同树种的不同部位灰分质量分数由高到低排列，兴安落叶松为枝、皮、干，而白桦为皮、枝、干；3）樟子松的干的灰分质量分数最小，枝和皮灰分质量分数相差不大。基于灰分质量分数单因子考虑，3种树种的下部树枝的抗火性能最强。

As h Contents Analysis of Main Pra ts in Differen t Diameter Tr ees

By the combination of field survey and indoor combustion method , we determined skin , dry and branch of ash content for three kinds of main tree species in the Daxing ’ an Moutains forest region , and discussed the ash content of each part of the main tree species of combustibility .By comparative analysis , the ash content of conifer and broadleaf cadres were the lowest, and the branches of the ash content from under the canopy were increased .The ash content orders in different parts of the same tree species from high to low were branches , skin and trunk for Larix gmelini , and bark , branches , and trunk for Betula platyphylla.The ash content of Pinus sylvesstris trunk is minimum , but similar in branch and skin .Considering the ash content with the single factor , the lower part branch of three tree species had the maximum fire-resistance.