Forests

Abstract

A forest may be defined as a collection of trees occupying a certain ground area and forming an ecosystem together with many other living and dead organisms in an inorganic environment including the mineral soil and atmosphere. The components of such an ecosystem interact with one another. To be called a forest, it is indispensable that the trees influence each other and are not independent as in a park or savanna. The crowns of the trees in the ecosystem make a layer called the crown canopy, and when they make a continuous canopy we say that the forest is closed. Trees growing in a closed forest and making a crown canopy have a very different shape from isolated independent trees (Honer 1971). When grown in isolation, foliage is produced almost to ground level, and, as such trees mature, this foliage increases exponentially (Madgwick et al. 1977). However, when grown in a closed forest, tree crowns are shaded by neighbouring trees and the amount of foliage for a tree of given diameter is greatly reduced compared with open-grown trees of the same species.