THE MANAGEMENT POTENTIAL OF NEOTROPICAL SECONDARY LOWLAND RAIN-FOREST

The management potential of neotropical secondary lowland rain forests is reviewed in the light of the increasing land area occupied by them and the continuing destruction of primary forests. The ecological group of long-lived intolerant trees, or big pioneers, is shown to consist almost exclusively of commercial or utilizable trees which are abundant and fast-growing in secondary rain forests throughout the neotropics. The timbers are relatively light and lack natural durability but these factors do not constitute problems for utilization. The Trinidad Shelterwood System is analysed, demonstrating the technical and economic feasibility of secondary forest management in situations in which markets accept timbers of long-lived intolerant species. It is concluded that while the biological management potential of secondary forests is general in the neotropics, favourable market conditions are not, but the growing demand for and shrinking supply of forest products should change this in the future. A population-based model of secondary succession is used as the framework for a simple preliminary sequence of silvicultural treatments, based upon a monocyclic approach. The ecological sustainability of secondary forest management is considered to depend on the maintenance of ecosystem function which, on poor soils, may be broken down by the relatively intensive interventions of a monocyclic system. This is by no means certain, however, and research is needed. Secondary forests usually constitute habitat islands and this must be taken into account in their management, especially with respect to natural regeneration from seed. The relatively high productivity of secondary forests and their potential for management through simple operations, in combination with certain crops if desired, are considered to suit them for incorporation into small and medium farm production systems.