Light-related competitive effects of overstory trees on the understory conifer saplings in a subalpine forest
Light-related competitive effects of overstory trees on the understory conifer saplings in a subalpine forest
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亚高山森林上层树木对林下针叶树幼苗的光相关竞争效应
DOI：
10.1007/s10310-002-0022-y
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发表时间：
2003
影响因子：
1.5
通讯作者：
H. Takeda
中科院分区：
文献类型：
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作者：
A. Mori;H. Takeda
为了阐明林下树苗遮荫的机理，我们研究了林下树苗光照条件（间接立地因子；ISF和直接立地因子；DSF）、林下树苗竞争效应(W)和林下树苗相对高度生长率（RHGR）之间的关系。为了找到最适合表达光照条件的w值，我们计算了多个w值，结果表明，在我们给出最佳拟合的情况下，w只解释了光照条件总方差的21.9%-24.7%。在本研究中，ww是基于上层乔木的基底面积计算的。然而，众所周知，冠层结构也会影响森林林下的光照状况，这可能会产生误差，即使在最充分地代表遮阳效应的w内。因此，尽管w显著地代表了上层树木的遮阳效应，但仍有很大比例的方差无法用w来解释。RHGR与w呈负相关，且对遮阳效应解释最充分的w值与RHGR负相关最好。这证明了林下树木对树苗生长的竞争效应是由遮荫效应介导的，表明林内明显存在对光的竞争。这种对光的竞争可能与日本中部亚高山森林中众所周知的林隙更新现象密切相关。
To clarify the mechanism by which overstory trees shade understory saplings, we investigated the relationships among light conditions of the saplings (measured as indirect site factor; ISF and direct site factor; DSF), the calculated competition effects of overstory trees on the saplings (W), and relative height growth rate of the saplings (RHGR). We calculated severalWvalues in order to find aWvalue which can express the light conditions as appropriately as possible, and the results indicated thatWexplained only 21.9%–24.7% of the total variance of light conditions in the cases whereWgave the best fit. In this study,Wwas calculated based on the basal areas of overstory trees. However, it is known that canopy structure also affects the light regimes in the forest understory, and this might yield the possible errors even withinWrepresenting the shading effects most adequately. Therefore, althoughWsignificantly represents the shading effect from overstory trees, a great proportion of the variance remained without being explained byW. RHGR was negatively correlated withW, and theWvalue which had the most adequate explanation of the shading effect also showed the best negative correlation with RHGR. This provides the evidence that the competitive effect of overstory trees on sapling growth is mediated by the shading effect, indicating that competition for light clearly exists within this forest. Such competition for light may closely relate to the well-known phenomenon of gap regeneration in subalpine forests in central Japan.
DOI：
--
发表时间：
2006
期刊：
Tree Physiology 26
影响因子：
--
作者：
BARNOR;M.T.;H.Hayakawa;H. Fujii;M.A.A.M.A.El-Rahman;H.B.KC;M. Murai;Y. Takemura and M. Urabe;En-Mi Lim;Kiyoshi Umeki
通讯作者：
Kiyoshi Umeki