Length of the growing season as a key determinant of spatial variation in forest surface litter quantity

Forest surface litter is an integral component of forest ecology, it acts as bridge between biotic and abiotic components of any forest ecosystem. Comprehensive, wall-to-wall mapping of forest litter distribution can enhance our understanding of ecosystem processes and nutrient dynamics, and improve management interventions and strategies for forest fire prevention and control. Forest phenology refers to start of season (SOS), peak of season (POS), end of season (EOS) and length of season (LOS). Thereby can be a potential indicator of accumulated surface litter quantity. However, these parameters are seldom used in estimation of surface litter. This study explored the prospective use of optical satellite-derived forest phenological metrics along with vegetation indices, LiDAR canopy-height and C-band SAR backscatter in estimation of surface litter quantity. Interestingly, the study found LOS (31.39%) to be the most important contributor to litter quantity estimation, followed by comparable contributions from LSWI (23.01%) and CRI2 (20.15%). SOS, POS and EOS had negligible contribution in explaining the spatial variability of accumulated surface litter. The study highlights the integrated use of LOS with canopy parameters that are indicator of vegetation stress and phase of leaf development can help in reliable estimation of forest surface litter quantity.