Effects of thinning-induced changes in structural heterogeneity on growth, ingrowth, and mortality in secondary coastal Douglas-fir forests
Effects of thinning-induced changes in structural heterogeneity on growth, ingrowth, and mortality in secondary coastal Douglas-fir forests
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DOI：
10.1139/cjfr-2015-0113
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发表时间：
2015-11-01
影响因子：
2.2
通讯作者：
Puettmann, Klaus J.
中科院分区：
文献类型：
--
作者：
Kuehne, Christian;Weiskittel, Aaron R.;Puettmann, Klaus J.
间伐被认为是加速后期演替属性的发展，从而提高了年轻的次生林林分结构的异质性。利用40~60年生沿海花旗松的大尺度试验，（花旗松（Mirbel）Franco）森林，我们解决了以下目标：（i）确定三种间伐处理对时间动态的影响（间伐后的前11年）主要森林结构措施，（ii）评估空间显式结构多样性度量与空间非显式林分度量之间的关系，以及（iii）测试林分结构与观测到的周期性林分蓄积生长，向内生长，and mortality.处理包括高密度，中密度，变密度间伐，从下面，以及控制。林分结构异质性处理之间的差异大多不显着。然而，我们的研究结果表明，变密度的立场显示结构丰富的树木大小和树种多样性增加，在整个研究期间，由于持续向内生长的物种比道格拉斯冷杉。简单的空间非显式指标不能用来可靠地模拟空间显式结构多样性措施。包括结构和物种多样性措施很少提高准确性的样地水平的增长，向内生长，死亡率预测模型。尽管这项研究的短期性质，我们得出结论，变密度间伐在增加结构异质性在年轻的同龄人的立场显示出希望。在生长和死亡率模型中纳入结构多样性措施可能是有益的，但需要进一步的工作来澄清潜在的关系，特别是在个体树一级。
Thinning is believed to accelerate the development of late-successional attributes, thereby enhancing stand structural heterogeneity in young, secondary forests. By making use of a large-scale experiment implemented in 40- to 60-year-old coastal Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) forests, we addressed the following objectives: (i) determine the effect of three thinning treatments on the temporal dynamics (first 11 years after thinning) of key forest structure measures, (ii) evaluate the relationships between spatially explicit structural diversity measures and spatially nonexplicit stand metrics, and (iii) test the relationships between stand structure and observed periodic stand volume growth, ingrowth, and mortality. Treatments consisted of high-density, moderate-density, and variable-density thinnings-from-below, as well as a control. Differences in stand structural heterogeneity between treatments were mostly nonsignificant. However, our results suggest that variable-density stands displayed structural enrichment as tree size and tree species diversity increased throughout the study period as a result of continuous ingrowth of species other than Douglas-fir. Simple spatially nonexplicit metrics could not be used to reliably model spatially explicit structural diversity measures. The inclusion of structural and species diversity measures only rarely improved accuracy of sample plot level growth, ingrowth, and mortality prediction models. Despite the short-term nature of this study, we conclude that variable-density thinning shows promise in increasing structural heterogeneity in young even-aged stands. The inclusion of structural diversity measures in growth and mortality models may be beneficial, but further work is needed to clarify the underlying relationships, particularly at the individual-tree level.