Relationship Between Leaf Area Index and Atmospheric Cooling of Tree Species

Abstract

Presence of tree canopy is known to strongly influence ambient temperature and other micro-climatic conditions underneath. Therefore, planting trees with close or dense crown can be used as effective measure to provide thermal cover to species of flora and fauna adapted to shady and cooler environment. The cooling produced by a tree is exclusively the combined results of physical and physiological functions of its canopy. Tree canopy is one of the most important, physiologically active components that establish interaction between the terrestrial environment and the atmosphere which regulates various bio-physiological processes. Leaf Area Index (LAI) is one of the most reliable indicators of growth and vigour of a tree. We compared LAI and corresponding understory temperature of a few isolated trees of Ficus benjamina, Mangifera indica, Anthocephalus chinensis, Lagerstroemia floribunda and Peltophorum africanum belonging to evergreen, semi-deciduous and deciduous nature to establish the relationship between the two parameters. A great variation in LAIs of deciduous and semi-deciduous species was observed on account of leaf shedding and fast development of crown after emergence of new leaves whereas the variation was lesser in evergreen species. A strong positive correlation was found between LAI and cooling produced by A. chinensis, L. floribunda and P. africanum whereas no linear relation was established in case of M. indica and F. benjamina.