Power law scaling relationships link canopy structural complexity and height across forest types
Power law scaling relationships link canopy structural complexity and height across forest types
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DOI：
10.1111/1365-2435.13983
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发表时间：
2021-12-19
影响因子：
5.2
通讯作者：
Gough, Christopher M.
中科院分区：
文献类型：
--
作者：
Atkins, Jeff W.;Walter, Jonathan A.;Gough, Christopher M.
1.森林冠层结构复杂性(CSC)是一种新兴的生态系统属性，在控制生态系统生产力、资源获取和资源利用效率方面起着关键作用，但在广泛的地理尺度上表现不佳，难以从样地提升到景观。在这里，我们通过分析17个横跨17个纬度的温带森林站点的激光雷达获取的CSC数据，证明了树冠高度和CSC之间的关系可以用幂定律来解释。在落叶阔叶林、常绿针叶林和混交林三种植物功能类型中，CSC随林高呈近似幂函数增加。在常绿针叶林中，树冠高度的增加不会导致复杂性的增加，其幅度与其他森林类型相同。我们将高度斜率的差异：森林类型之间的复杂关系归因于：(A)常绿针叶树种之间树冠结构相对于阔叶树种的多样性有限；(B)垂直森林分层随高度发展的差异；以及(C)针叶树种的竞争排除。我们通过对18个国家生态观测网络站点的4,324棵树的分析表明，阔叶树种和针叶树种之间的树冠几何形状与树高的关系一致，从而支持了这些潜在的机制。森林高度和CSC之间的幂规律关系对于森林结构属性的建模、尺度和绘图具有广泛的意义。我们的结果表明，森林研究和管理应考虑森林高度与CSC之间的比例关系的非线性，这些关系的性质可能因森林类型而不同。
1. Forest canopy structural complexity (CSC), an emergent ecosystem property, plays a critical role in controlling ecosystem productivity, resource acquisition and resource use-efficiency; yet is poorly characterized across broad geographic scales and is difficult to upscale from the plot to the landscape.2. Here, we show that the relationship between canopy height and CSC can be explained using power laws by analysing lidar-derived CSC data from 17 temperate forest sites spanning over 17 degrees of latitude. Across three plant functional types (deciduous broadleaf, evergreen needleleaf and mixed forests), CSC increases as an approximate power law of forest height. In evergreen needleleaf forests, increases in canopy height do not result in increases in complexity to the same magnitude as in other forest types.3. We attribute differences in the slope of height:complexity relationships among forest types to: (a) the limited diversity of crown architectures among evergreen conifer trees relative to broadleaf species; (b) differences in how vertical forest layering develops with height; and (c) competitive exclusion by needleleaf species. We show support for these potential mechanisms with an analysis of 4,324 individual trees from across 18 National Ecological Observatory Network sites showing that crown geometry-to-tree height relationships differ consistently between broadleaf and needleleaf species.4. Power law relationships between forest height and CSC have broad implications for modelling, scaling and mapping forest structural attributes. Our results suggest that forest research and management should consider the nonlinearity in scaling between forest height and CSC and that the nature of these relationships may differ by forest type.