Individual-tree radial growth in a subtropical broad-leaved forest: The role of local neighbourhood competition
Individual-tree radial growth in a subtropical broad-leaved forest: The role of local neighbourhood competition
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DOI：
10.1016/j.foreco.2010.10.035
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发表时间：
2011-02
影响因子：
3.7
通讯作者：
G. Oheimb;Anne Lang;H. Bruelheide;D. Forrester;Ilka Wäsche;Mingjian Yu;W. Härdtle
中科院分区：
文献类型：
--
作者：
G. Oheimb;Anne Lang;H. Bruelheide;D. Forrester;Ilka Wäsche;Mingjian Yu;W. Härdtle
建立在当地邻里水平的竞争关系是必不可少的，以提高我们的理解树木生长动态结构异质性和物种丰富的森林。本文研究了影响栲树（Castanopsis fargesii（Franch.）和白栎（Quercus fabri（Hance））在中国东部万年青阔叶次生林（EBLF）中的分布。不同的空间明确的个人为基础的竞争指数进行了检查，其有效性在预测径向增长。这些指数的基础上的三个树的大小变量-直径在胸高（DBH），总高度，树冠投影面积-并结合不同的方法来识别潜在的竞争对手。此外，我们测试了竞争等价的同种和异种邻居和分析的影响，当地的多样性，初始胸径（在开始的五年生长期）和非生物环境变量对个体树径向生长。竞争可分别解释杉木径向生长变异的78%和75%。fargesii和Q. Fabri，分别。最好的结果提供了竞争指数，使用冠投影面积作为变量描述树的大小和角高度的方法，以确定潜在的竞争对手（即邻居大于最小角高度，从目标树的基础上测量，被选为竞争对手）。在C. fargesii，而在Q.法布里。我们不能检测径向生长的多样性效应。增加初始胸径或非生物环境变量作为进一步的解释变量未能提高生长模型的预测能力。我们的研究结果表明，在这个EBLF的直径增长在很大程度上是一个功能的本地邻里竞争，并建议的竞争模式主要是大小不对称的。不同物种之间似乎存在高度竞争性等效性，但这仍有待实验验证。
Establishing the competitive relationships at the local neighbourhood level is essential for improving our understanding of tree growth dynamics in structurally heterogeneous and species-rich forests. We studied the competitive interactions influencing individual-tree five-year radial growth of the two species Castanopsis fargesii (Franch.) and Quercus fabri (Hance) in a diverse young secondary evergreen broad-leaved forest (EBLF) in eastern China. Different spatially explicit individual-based competition indices were examined for their effectiveness at predicting radial growth. These indices were based on one of the three tree size variables – diameter at breast height (dbh), total height, and crown projection area – and were combined with different approaches to identify potential competitors. Furthermore, we tested for competitive equivalence of conspecific and heterospecific neighbours and analysed the effects of local diversity, initial dbh (measured at the beginning of the five-year growth period) and abiotic environmental variables on individual-tree radial growth. Competition accounted for up to 78% and 75% of radial growth variation in C. fargesii and Q. fabri, respectively. The best results were provided by competition indices using crown projection area as the variable describing tree size and the angular height method as the approach to identify potential competitors (i.e. neighbours greater than the minimum angular height, measured from the base of the target trees, are selected as competitors). Competitive equivalence of conspecific and heterospecific neighbours was found in C. fargesii, whereas heterospecifics were stronger competitors than conspecifics in Q. fabri. We could not detect diversity effects on radial growth. The addition of initial dbh or abiotic environmental variables as further explanatory variables failed to improve the predictive ability of growth models. Our results indicate that diameter growth in this EBLF is largely a function of local neighbourhood competition and suggest that the mode of competition is primarily size-asymmetric. It appears that there may be high competitive equivalence among different species, but this remains to be experimentally tested.