Thinning alters crown dynamics and biomass increment within aboveground tissues in young stands of Chamaecyparis obtusa
Thinning alters crown dynamics and biomass increment within aboveground tissues in young stands of Chamaecyparis obtusa
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DOI：
10.1007/s10310-013-0405-2
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发表时间：
2014-02
影响因子：
1.5
通讯作者：
Q. Han;Daisuke Kabeya;S. Saito;M. Araki;T. Kawasaki;Chiharu Migita;Y. Chiba
中科院分区：
文献类型：
--
作者：
Q. Han;Daisuke Kabeya;S. Saito;M. Araki;T. Kawasaki;Chiharu Migita;Y. Chiba
森林的林分密度影响树叶的垂直分布。了解这种响应的动态对于研究树冠结构和功能、碳收支估算和森林管理都很重要。通过连续4年对10年生钝叶决明间伐和未间伐对照林分各5株树木的一级枝生长进行监测，研究了树木密度对叶片、分支和茎生长的垂直分布以及地上部分生物量增长率的影响。在对照林分中，随着树高的增加，树冠的叶量向上移动，但整个树冠的叶量并没有增加。此外，叶重的垂直分布也由树冠下部偏态向树冠上部偏态转移。在间伐林分中，4年内树冠叶量增加了2倍，但叶量的垂直分布仍呈下冠偏态。两种林分的生产率、单位树高的一级枝数和一级枝总长度相似。但对照林分一级枝死亡率和一级分支内自剪率显著高于间伐林分，导致分支生物量增长率较高。间伐诱导了叶片生物量增长率较高，分支生物量增长率较低。间伐后叶片数量的增加和生物量增长率的变化促进了残株的树干生长。这些结果提供的信息，将是有用的，当考虑间伐制度和林分管理。
The stand density of a forest affects the vertical distribution of foliage. Understanding the dynamics of this response is important for the study of crown structure and function, carbon-budget estimation, and forest management. We investigated the effect of tree density on the vertical distribution of foliage, branch, and stem growth, and ratio of biomass increment in aboveground tissues; by monitoring all first-order branches of five trees each from thinned and unthinned control stands of 10-year-oldChamaecyparis obtusafor four consecutive years. In the control stand, the foliage crown shifted upward with height growth but the foliage quantity of the whole crown did not increase. In addition, the vertical distribution of leaf mass shifted from lower-crown skewed to upper-crown skewed. In the thinned stand in contrast, the foliage quantity of individual crowns increased two-fold within 4 years, while the vertical distribution of leaf mass remained lower-crown skewed. The two stands had similar production rates, numbers of first-order branches per unit of tree height, and total lengths of first-order branches. However, the mortality rate of first-order branches and self-pruning within a first-order branch were significantly higher in the control stand than in the thinned stand, which resulted in a higher ratio of biomass increment in branch. Thinning induced a higher ratio of biomass increment in foliage and lower in branch. The increased foliage quantity and variation in ratio of biomass increment after thinning stimulated stem growth of residual trees. These results provide information that will be useful when considering thinning regimes and stand management.