Root anchorage and stem strength of black spruce (Picea mariana) trees in regular and irregular stands
Root anchorage and stem strength of black spruce (Picea mariana) trees in regular and irregular stands
复制标题
规则和不规则林分黑云杉（Picea mariana）树的根系固着和茎强度
DOI：
10.1093/forestry/cpn035
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发表时间：
2009
期刊：
影响因子：
2.8
通讯作者：
S. Mitchell
中科院分区：
文献类型：
--
作者：
C. Bergeron;Jean;Jean;S. Mitchell
为了评估黑云杉（Picea mariana（Mill.）B.S.P.）规则和不规则结构林分中的树木。通过统计分析，确定了被吊木的临界弯矩（Mc），并探讨了Mc与树木和林分特征的关系。树干质量（SW）、平均株距（S）和高径比（H /d.b.h.）最初通过筛选程序选择来预测Mc。林分结构之间的潜在差异进行了测试，在混合模型中使用不同的数据子集。不同模型之间的固定效应不同。SW是所有模型中最有用和最重要的变量，H /d.b.h.只有当分析中包括折断的树木时才有意义。当腐烂的样品被排除在外，抗拔出更高的不规则的立场。腐烂似乎发挥了重要作用，在不规则的林分，应进一步调查。由于在远端部位之间未观察到股骨柄质量和临界转动力矩之间的关系存在差异，因此这种关系应适用于广泛的区域。这项研究提供了一些基本的关系，需要在不规则的林分风吹风险模型。然而，还需要考虑林分结构对个别树木风荷载的影响。
Summary A tree winching experiment was conducted, simulating wind action and resulting damage, in order to assess mechanical resistance of black spruce ( Picea mariana (Mill.) B.S.P.) trees in stands of regular and irregular structures. The critical bending moment ( M c ) of winched trees was determined and the relationship between M c and tree and stand characteristics was investigated through statistical analyses. Stem mass ( SW ), average spacing between trees ( S ) and height:diameter ratio ( H /d.b.h.) were initially selected by a screening procedure to predict M c . Potential differences between stand structures were tested in mixed models using different subsets of the data. Included fi xed effects varied between the different models. SW was the most useful and signifi cant variable in all models and H /d.b.h. was signifi cant only when snapped trees were included in the analysis. When decayed samples were excluded, resistance to uprooting was higher in irregular stands. Decay seemed to play an important role in irregular stands and should be investigated further. Since no difference was observed in the relationship between stem mass and critical turning moment between distant sites, relationships should be applicable across wide regions. This study provides some of the basic relationships required to model windthrow risk in irregular stands. However, the effects of stand structure on wind load for individual trees will also need to be considered.