At the Fringes of the Rain Forest

Abstract

The natural limits of the rain forest are defined by climate and soil. The altitude above sea level influences temperature and is consequently an aspect of climate. We have already seen that ‘seasons’ in the tropics are primarily dry as opposed to wet seasons, which can, like altitude, impose serious biological limitations. Then there are the edaphic or soil factors. First of all is the (ground) water level. Where it is too near the surface for the greater part of the year, it is impossible for many plants to grow. Another limiting factor is the quantity of available inorganic nutrients which may be too small in some soils, even for the tolerant rain forest plants.