Factors affecting species richness of tree regeneration in mixed‐wood stands of central Maine
Factors affecting species richness of tree regeneration in mixed‐wood stands of central Maine
复制标题
影响缅因州中部混交林树木再生物种丰富度的因素
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
R. Wagner
中科院分区：
文献类型：
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作者：
M. Olson;R. Wagner
问：本文讨论了两个关于林内空间变异性的问题。树木更新的物种丰富度如何响应小尺度生态梯度，天然香脂冷杉丰度对其他树木更新的物种丰富度有何影响？
地点：美国缅因州的密混交林，一项长期的林隙培育试验。
研究方法：8个林分处理和不间隙收获进行了采样，以捕获子林分异质性林下树木更新同时与当地的林分条件的格局。建立了空间和非空间模型来检验2个响应变量[小更新（高度≥ 0.1m，但<0.75m）和大更新（高度≥ 0.75m，但<1.4m）的物种丰富度]与5个解释变量（地下水位深度、冠层透光率、A.更新密度、林下断面积和物种丰富度）。
结果如下：尽管所有模型的不可解释方差都很高，但变量之间的关联性是一致的：（1）小更新的物种丰富度与A。（2）大面积更新和越层断面积的物种丰富度。结果表明：（1）小更新林的物种丰富度与林下断面积和物种丰富度呈正相关;（2）大更新林和小更新林的物种丰富度与林冠透光率呈正相关。
结论：促进树种多样性在埃塞俄比亚混合木材的立场可能无法实现通过单独使用间隙采伐，如果下层冷杉balsamea的密度不自然减少或通过造林干预。
Question: Two questions about within-stand spatial variability are addressed in this paper. How does species richness of tree regeneration respond to small-scale ecological gradients, and what effect does natural Abies balsamea abundance have on the species richness of other tree regeneration?
Location: A long-term, gap-silviculture experiment, Acadian mixed-wood forest, Maine, USA.
Methods: Eight stands treated with and without gap harvesting were sampled to capture sub-stand heterogeneity of understorey tree regeneration concurrently with patterning of local stand conditions. Spatial and non-spatial models were developed to test the relationships between two response variables [species richness of small (height ≥0.1 m, but <0.75 m) and large (height ≥0.75 m, but <1.4 m) regeneration] and five explanatory variables (depth to water table, percentage canopy transmittance, A. balsamea regeneration density, and overstorey basal area and species richness).
Results: Despite high unexplained variance for all models, consistent associations among variables were found. Negative associations were found between: (1) the species richness of small regeneration and A. balsamea regeneration density and (2) the species richness of large regeneration and overstorey basal area. Positive associations were found between: (1) the species richness of small regeneration and both overstorey basal area and species richness and (2) the species richness of small and large regeneration and canopy transmittance.
Conclusions: Promoting tree species diversity in Acadian mixed-wood stands may not be achievable through the use of gap-harvesting alone if the density of understorey Abies balsamea is not reduced either naturally or through silvicultural intervention.