Syncing Phenology Phase and Canopy Spectral Reflectance of Common Tree Species of Four Forest Covers in India

Variability in the leaf phenology of tropical trees impacts their growth. How phenology of tree species responds over rainfall gradient is relevant to study in the light of current climatic changes. Airborne visible and infrared imaging spectrometer-next generation (AVIRIS-NG) spectral datasets have been considered for this study as they not only provide wider area of coverage, but also high spatial and spectrally resolved output. Canopy-level spectra of 16 common species of four different forest covers in India were synced with observed phenology phase and the annual rainfall in each forest cover was recorded. Reflectance spectra of the same species in the four forest covers distinctively differed over rainfall gradient, indicating intra-species pliability. Consistent lower reflectance/higher absorp-tion at chlorophyll bands of all the common deciduous species in the higher annual rainfall region over that with relatively lower rainfall indicated that deciduous species acclimate green foliage phase of the phenology cycle. Boxplots of reflectance values of chlorophyll absorption band of 16 species showed a decrease in the variability of the datasets over the four forest co-vers, revealing that increasing rainfall provides better synchrony in the phenology phase of the observed tree species. The study highlights the importance of AVIRIS-NG spectral datasets in monitoring different phases of forest phenology associated with growth potential dynamics effectively under changing rainfall pattern.