Leaf Canopy Layers Affect Spectral Reflectance in Silver Birch
Leaf Canopy Layers Affect Spectral Reflectance in Silver Birch
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DOI：
10.3390/rs11242884
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发表时间：
2019-12-02
期刊：
影响因子：
5
通讯作者：
Keinanen, Markku
中科院分区：
文献类型：
--
作者：
Deepak, Maya;Keski-Saari, Sarita;Keinanen, Markku
树冠内光照的有效性影响各种叶片特征和叶片反射率。测定了生长在同一园地的三种遗传相同的无性系白桦树在400~2500 nm范围内叶片反射率的变化。利用基于偏最小二乘判别分析的投影重要度变量(VIP)对冠层进行主成分分析(PCA)，确定影响冠层变化的波长。叶片性状，如叶绿素、氮素、干重和比叶面积(SLA)也在冠层之间表现出显著差异。我们发现冠层的红边拐点(REIP)发生了移动。冠层对反射率指数的变异性有贡献。结果表明，冠层间的差异最大，而各树种对叶片反射率的差异较小。这意味着在估测冠层反射率的种内变化时，应考虑冠层引起的树内差异。
The availability of light within the tree canopy affects various leaf traits and leaf reflectance. We determined the leaf reflectance variation from 400 nm to 2500 nm among three canopy layers and cardinal directions of three genetically identical cloned silver birches growing at the same common garden site. The variation in the canopy layer was evident in the principal component analysis (PCA), and the influential wavelengths responsible for variation were identified using the variable importance in projection (VIP) based on partial least squares discriminant analysis (PLS-DA). Leaf traits, such as chlorophyll, nitrogen, dry weight, and specific leaf area (SLA), also showed significant variation among the canopy layers. We found a shift in the red edge inflection point (REIP) for the canopy layers. The canopy layers contribute to the variability in the reflectance indices. We conclude that the largest variation was among the canopy layers, whereas the differences among individual trees to the leaf reflectance were relatively small. This implies that within-tree variation due to the canopy layer should be taken into account in the estimation of intraspecific variation in the canopy reflectance.