Rainforest

Natural rainforests are an extremely valuable natural resource, mostly because they typically contain very large individual trees of commercially desirable species. These trees can be harvested and manufactured into lumber, plywood, paper, and other valuable wood products. Tropical rainforests, for example, contain large trees of commercially important species of tropical hardwoods, such as African mahogany (Khaya and Entandrophragma spp.), American mahogany (Swietenia spp.), Asian mahogany (Shorea spp. and Parashorea spp.), balsa (Ochroma spp.), ebony (Diospyros spp.), rosewood (Dalbergia spp.), rubber (Hevea brasiliensis), and yang (Dipterocarpus spp.). Temperate rainforests are also extremely valuable, because their large trees can be harvested and converted into economic products.

However, because they have little or no net production of tree biomass, it is a common practice in industrial forestry to clear-cut old-growth rainforests and then convert them into more productive, secondary forests. Even though another forest regenerates on the harvested site, sometimes dominated by the same tree species that occurred initially, this practice should be viewed as an ecological conversion that results in a net loss of old-growth rainforest as a natural ecosystem. All ecological conversions have attendant risks for species that require the particular habitats of the original ecosystem.

In other cases, trees may be selectively harvested from old-growth rainforests so that the physical and ecological integrity of the forest is left more or less intact. This is especially true of temperate rainforests, which unlike tropical rainforests, do not have interlocking webs of lianas in their overstory, so that the felling of one large tree can bring down or badly damage other trees in its vicinity. However, even selective harvesting changes the character of old-growth rainforests, so that they are no longer in their natural condition. As such, the selectively harvested ecosystem would no longer provide habitat for many of the species that depend on the habitats available in the original, old-growth rainforest. Nevertheless, selective harvesting results in a much less intensive ecological conversion than that associated with clear-cutting.

Because old-growth rainforests are natural ecosystems, they are considered to have great intrinsic value, which is degraded when they are harvested or otherwise disturbed. The intrinsic value of rainforests is further enhanced by the enormous richness of species of plants, animals, and microorganisms that are dependent on this specific ecosystem, particularly in the tropics. Mostly because of the intrinsic biodiversity-related value of rainforests, it is critically important that not all of the world's tracts of these natural ecosystems are converted to human uses. To prevent this terrible damage from occurring, extensive landscapes of the world's remaining rainforests, in both tropical and temperate regions, must be protected in ecological reserves and parks, where no more than traditional uses by humans are permitted.