Plant functional diversity is strongly connected to photosynthetic carbon assimilation in terrestrial ecosystems. However, many of the plant functional traits that regulate photosynthetic capacity, including foliar nitrogen concentration and leaf mass per area, vary significantly between and within plant functional types and vertically through forest canopies, resulting in considerable landscape‐scale heterogeneity in three dimensions. Hyperspectral imagery has been used extensively to quantify functional traits across a range of ecosystems but is generally limited to providing information for top of canopy leaves only. On the other hand, lidar data can be used to retrieve the vertical structure of forest canopies. Because these data are rarely collected at the same time, there are unanswered questions about the effect of forest structure on the three ‐dimensional spatial patterns of functional traits across ecosystems. In the United States, the National Ecological Observatory Network's Airborne Observation Platform (NEON AOP) provides an opportunity to address this structure‐function relationship by collecting lidar and hyperspectral data together across a variety of ecoregions. With a fusion of hyperspectral and lidar data from the NEON AOP and field‐collected foliar trait data, we assessed the impacts of forest structure on spatial patterns of N. In addition, we examine the influence of abiotic gradients and management regimes on top‐of‐canopy percent N and total canopy N (i.e., the total amount of N [g/m²] within a forest canopy) at a NEON site consisting of a mosaic of open longleaf pine and dense broadleaf deciduous forests. Our resulting maps suggest that, in contrast to top of canopy values, total canopy N variation is dampened across this landscape resulting in relatively homogeneous spatial patterns. At the same time, we found that leaf functional diversity and canopy structural diversity showed distinct dendritic patterns related to the spatial distribution of plant functional types.

中文翻译：

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叶片性状和冠层结构共同解释了冠层功能的多样性：一种机载遥感方法

植物功能多样性与陆地生态系统中的光合作用碳同化密切相关。但是，许多调节光合作用能力的植物功能性状，包括叶面氮浓度和单位面积的叶质量，在植物功能类型之间和内部以及垂直穿过森林冠层变化很大，从而在三个维度上造成了相当大的景观尺度异质性。高光谱图像已被广泛用于量化一系列生态系统的功能性状，但通常仅限于仅提供冠层叶顶部的信息。另一方面，激光雷达数据可用于检索林冠层的垂直结构。由于很少同时收集这些数据，关于森林结构对整个生态系统功能性特征的三维空间格局的影响，还有一些未解决的问题。在美国，国家生态天文台网络的机载观测平台（NEON AOP）提供了一个机会，可以通过跨多个生态区域一起收集激光雷达和高光谱数据来解决这种结构与功能的关系。结合NEON AOP的高光谱和激光雷达数据以及野外收集的叶性状数据，我们评估了森林结构对氮空间格局的影响。此外，我们还研究了非生物梯度和管理制度对顶部氮的影响。 -冠层氮含量和冠层总氮含量（即N的总量[g / m 国家生态观测站网络的机载观测平台（NEON AOP）提供了一个机会，可以通过跨多个生态区域一起收集激光雷达和高光谱数据来解决这种结构与功能的关系。结合NEON AOP的高光谱和激光雷达数据以及野外收集的叶面性状数据，我们评估了森林结构对氮空间格局的影响。此外，我们还研究了非生物梯度和管理制度对顶部氮的影响。 -冠层氮含量和冠层总氮含量（即N的总量[g / m 美国国家生态天文台网络的机载观测平台（NEON AOP）提供了一个机会，可以通过跨多个生态区域收集激光雷达和高光谱数据来解决这种结构与功能的关系。结合NEON AOP的高光谱和激光雷达数据以及野外收集的叶性状数据，我们评估了森林结构对氮空间格局的影响。此外，我们还研究了非生物梯度和管理制度对顶部氮的影响。 -冠层氮含量和冠层总氮含量（即N的总量[g / m² ]在森林冠层内）在NEON地点，由开放的长叶松树和茂密的阔叶落叶林组成。我们得出的地图表明，与冠层值的顶部相反，整个冠层N的变化在整个景观中均被衰减，从而导致相对均匀的空间格局。同时，我们发现叶片功能多样性和冠层结构多样性表现出与植物功能类型的空间分布有关的明显树突模式。