Effects of local neighbourhood diversity on crown structure and productivity of individual trees in mature mixed-species forests
Effects of local neighbourhood diversity on crown structure and productivity of individual trees in mature mixed-species forests
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DOI：
10.1186/s40663-021-00306-y
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发表时间：
2021-04-26
影响因子：
4.1
通讯作者：
von Oheimb, Goddert
中科院分区：
文献类型：
--
作者：
Georgi, Louis;Kunz, Matthias;von Oheimb, Goddert
种特异性基因型特征，当地邻里的相互作用和资源供应强烈影响树的身高和生长速度。在混种林中，多样性介导的生物量分配被认为是生物多样性与生产力正相关的基本机制。经验证据，但是，是罕见的本地邻里多样性的影响，树木的特点分析在一个非常高的细节。为了解决这个问题，我们分析了这些影响在北方德国成熟的混交林的个体树冠结构和树木生产力。方法我们的分析考虑了多个目标树种在当地社区物种丰富度梯度范围从1到4。我们应用地面激光扫描量化了大量的个人成熟的树木（N = 920）在非常高的精度。我们评估了两种不同的邻居包含方法，通过分析固定半径的选择过程和基于重叠冠的选择。结果与结论研究表明，局部邻域物种多样性显著增加了目标树种的冠幅和木材蓄积量。此外，多样性对林木生产力（断面积和木材蓄积生长量）的影响具有一定的尺度依赖性，对胸径> 40 cm的大型林木具有正效应，对胸径< 40 cm的小型林木具有负效应。在我们的分析中，邻居包容方法对结果有重大影响。对于科学研究和增长模型的验证，我们建议通过重叠冠进行邻居选择，因为这似乎是当地邻居相互作用发生的相关尺度。由于当地的邻里多样性，促进个别树的生产力在成熟的欧洲混种森林，我们的结论是，小规模的物种混合物应考虑在管理计划。
Background Species-specific genotypic features, local neighbourhood interactions and resource supply strongly influence the tree stature and growth rate. In mixed-species forests, diversity-mediated biomass allocation has been suggested to be a fundamental mechanism underlying the positive biodiversity-productivity relationships. Empirical evidence, however, is rare about the impact of local neighbourhood diversity on tree characteristics analysed at a very high level of detail. To address this issue we analysed these effects on the individual-tree crown architecture and tree productivity in a mature mixed forest in northern Germany. Methods Our analysis considers multiple target tree species across a local neighbourhood species richness gradient ranging from 1 to 4. We applied terrestrial laser scanning to quantify a large number of individual mature trees (N = 920) at very high accuracy. We evaluated two different neighbour inclusion approaches by analysing both a fixed radius selection procedure and a selection based on overlapping crowns. Results and conclusions We show that local neighbourhood species diversity significantly increases crown dimension and wood volume of target trees. Moreover, we found a size-dependency of diversity effects on tree productivity (basal area and wood volume increment) with positive effects for large-sized trees (diameter at breast height (DBH) > 40 cm) and negative effects for small-sized (DBH < 40 cm) trees. In our analysis, the neighbour inclusion approach has a significant impact on the outcome. For scientific studies and the validation of growth models we recommend a neighbour selection by overlapping crowns, because this seems to be the relevant scale at which local neighbourhood interactions occur. Because local neighbourhood diversity promotes individual-tree productivity in mature European mixed-species forests, we conclude that a small-scale species mixture should be considered in management plans.