Leaf Shape and Self-Mulching by Trees: A Hypothesis

The simple leaves of deciduous forest trees in temperate zones have more irregular and asymmetric shapes than comparable non-deciduous the tropics subtropics. These manifest as lobes sinuses species Quercus Acer, well greater bilateral asymmetry Ulmaceae Betulaceae, serrated margins many species, frequency compound generally (Fraxinus Carya). modifications may contribute to an early transition from laminar turbulent flow, thus reducing lateral movement when they drop during onset either winter or dry season, are simply shed for replacement. Such likely over critical root zone large, thin, broadly elliptic, symmetric leaves. Here, we evaluate evidence against self-mulching explanation differences leaf shape between tropical forests. We suggest that main evolutionary trade-offs competition (1) light among subcanopy trees, (2) water soil nutrients canopy trees.