Synnott and Kemp

Although tropical moist rainforest ecosystems are of enormous interest to science, with great potential for development, their ecology and biology are poorly understood. Available data is sketchy and often inadequate for planning and policy development. The taxonomy of many trees and shrubs remains weak, and many species are unnamed.

A fundamental feature of tropical moist forest ecosystems is their complexity. Whilst this is a major problem for the manager, it is a major strength of the system, in regard both to environmental hazards and to changing demands. The need to simplify and refine the system for wood production must therefore be set against the desirability of retaining the wealth of variability that may be required to adapt to future changes. It may be necessary, however, and is certainly possible, for these two largely incompatible processes to be carried out separately, in different parts of the forest.

Evidence shows that the productivity of the tropical rain forest comes from good growing conditions, constituted by a combination of high temperatures, light and rainfall all year round, coupled with efficient nutrient recycling processes.

Ecological studies of tropical forests are concerned with how the biotic component (plant and animal species, or the living component) interacts with abiotic factors (the non-living component of the substrate, nutrients, moisture, and climate). Sustainable management of secondary forests calls for a clear understanding of how species interact with the biotic and abiotic environment.

The biggest challenge facing forest management today is the development of strategies to adopt sustainable forest management practices. This is called multipurpose management, in which the overall capacity of forests to provide goods and services is not diminished. This calls for a firm knowledge and understanding of the resource base (resource inventory as a basis of stand history, structure, species composition, diversity, and dynamics), and availability and implementation of environmentally sound forest harvesting practices.

Synnott and Kemp16 (1976) discussed the initial reliance on natural regeneration in most areas of tropical moist forest to provide the future crop. The silvicultural techniques have been intended to increase the stocking and growth rates of seedlings of valuable species, but techniques for inducing regeneration of chosen species have often been unreliable. In practice, it has only proved possible to directly increase the stocking of valuable seedlings if silvicultural operations can be timed to coincide with abundant seed-fall of valuable species. More success has been achieved with operations which increase the survival rates and sometimes the growth rates of existing valuable young trees by reducing competition from unwanted trees. Some techniques improve the proportion of valuable trees in a standby eliminating unwanted trees without necessarily increasing their growth rates of seedling numbers.

Formerly, uniform systems (especially those termed shelterwood systems) were designed to achieve abundant regeneration of valuable species by careful manipulation of the canopy.

16 Synnott TJ & Kemp R H 1976 Choosing the best silvicultural system. Unasylva No 112-113 Vol 28 1976 topic Management and Utilisation of Tropical Moist Rainforest.