Leaf dynamics and maintenance of tree crowns in a Malaysian rain forest stand
Leaf dynamics and maintenance of tree crowns in a Malaysian rain forest stand
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马来西亚雨林的叶子动态和树冠的维护
DOI：
10.1046/j.0022-0477.2001.00590.x
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发表时间：
2001
影响因子：
5.5
通讯作者：
M. Awang
中科院分区：
文献类型：
--
作者：
N. Osada;H. Takeda;A. Furukawa;M. Awang
1 对马来西亚热带雨林中不同高度树木的叶子人口统计进行了 3.7 年的检查。我们比较了树冠上部和下部的人口统计特征及其与身高的关系。通过汇集不同耐荫树种的几棵树以及对多个个体进行采样的三个树种，在林分水平上对结果进行了分析。 2 上冠的光子通量密度通常高于下冠。大多数树木的上部树冠的产叶率和失叶率较快，因此叶群数量和中位叶寿命较低。尽管叶子生产率不受影响，但叶子损失速度加快和寿命缩短与高度增加有关。 3 在几种耐荫树种中，叶子寿命和比叶面积是可塑性状，随着高度的增加而减小，表明功能趋同。 4 林分中叶片生物量的垂直分布几乎均匀。由于树冠上部的叶子寿命较短，这些叶子对凋落物的产生贡献最大。因此，林分的垂直结构是通过短时间内不同高度的树木的动态过程来维持的。
1 Leaf demography was examined for trees of various heights over a 3.7‐year period in a Malaysian rain forest. We compared demography between upper and lower parts of the crown and its relation to height. The results were analysed at the stand level by pooling several trees of various shade‐tolerant species, as well as three species for which multiple individuals were sampled. 2 Photon flux density was generally higher in the upper than in the lower crowns. Leaf production rate and leaf loss rate were faster, and number of leaf cohorts and median leaf life span were therefore lower, in the upper crowns of most trees. Faster rates of leaf loss and shorter life spans were associated with increasing height, although leaf production rate was unaffected. 3 Leaf life span and specific leaf area were plastic traits which decreased with height within several shade‐tolerant tree species, indicating functional convergence. 4 Vertical distribution of leaf biomass was almost even in the stand. Because leaf life span was shorter in the upper canopy, these leaves contributed most to litter production. The vertical structure of the forest stand was therefore maintained through dynamic processes in trees of various heights over short time‐scales.