Estimation of Canopy Leaf Area Index of Tropical Rainforests of Sri Lanka from the Normalized Difference Vegetation Index along a Wide Altitudinal Gradient

A significant linear decrease in canopy Leaf Area Index (LAI) and Normalized Difference Vegetation Index (NDVI) with increasing altitude was observed in Sri Lankan tropical rainforests, highlighting the impact of elevation on forest structure. The study found that LAI decreases by 0.396 units per 1,000 meters of altitude rise, with second-order polynomial functions providing a better fit for data than linear models. Two predictive models were developed using NDVI metrics and canopy architectural properties, achieving adjusted-R² values up to 0.544. The research utilized hemispherical photography and satellite imagery from Landsat 8 to analyze LAI and NDVI across seven forest reserves spanning altitudes from 117 to 2,132 meters.

Madhumali R.M.C., Wahala W.M.P.S.B., Welikanna D.R., Dunendran P., Sanjeewani H.K.N., Samarasinghe D.P., & De Costa W.A.J.M. (2022). Estimation of Canopy Leaf Area Index of Tropical Rainforests of Sri Lanka from the Normalized Difference Vegetation Index along a Wide Altitudinal Gradient. Proceedings of International Forestry and Environment Symposium, 26. https://doi.org/10.31357/fesympo.v26.5561