Differentiation of Tropical Tree Species with Leaf Measurements of Hyperspectral Reflectance

Abstract

The development of non-destructive indicators of leaf-level hyperspectral reflectance is the first step in mapping endangered tree species in the tropics. Therefore, hyperspectral reflectance at the leaf level was implemented to differentiate 15 tree species from Costa Rica’s forests. The hyperspectral reflectance (310 to 1100 nm) was evaluated in six individuals per species (30 leaves per individual) in the rainy season. In addition, the specific leaf area (SLA) and leaf thickness (LT) were evaluated. The data were first analyzed by one-way ANOVA to identify differentiating bands between species. Then, linear discriminant analysis (LDA) was used to classify the species and define the degree of similarity, and the contribution of each narrow band to the classification was estimated with the absolute value of the standardized coefficients associated with the discriminant function (kappa value). Subsequently, we determined whether the SLA or LT correlated with the species differentiation. The results showed that the wavebands al 350, 700, 750, 780, 790, 800, and 1010 nm were key to differentiating the species, with an average kappa value of 0.88. Furthermore, the correlation of the hyperspectral reflectance with the SLA and LT was ruled out. Our results suggest the value of differentiating tropical tree species through non-destructive methods, which can facilitate the mapping of endangered populations and the development of conservation strategies.

Keywords

• conservation
• tree
• species
• tropics