Geoscience Reference
In-Depth Information
Food trees
Crops under shade
e.g. coffee, cocoa
Beekeeping,
forage trees
Pasture-legumes,
grasses, herbage,
grazing animals
Forage and food trees,
grazing animals
underneath
Plantations of fast-growing
species for wood production
and firewood
Source: After Simmonds (1989)
KEY POINTS
1
The humid tropics cover the warmest parts of the globe where there is, on average, a water surplus. Rain
falls throughout the year, associated with the equatorial trough, though there may be a drier season when
the active trough is farthest away. Seasonal temperature variations are small and diurnal control is
strongest.
2
Because of the humid conditions the soils are the product of rapid weathering and strong leaching. Organic
matter decomposes rapidly, so its maintenance at suitable levels is one of the key problems of tropical
soil utilization.
3
Tropical rain forest is diverse in species composition and structure. Yet at the same time it exhibits a fragile
system. There are complex relationships within the ecosystem which can easily be disturbed or broken.
Many forests have been severely degraded in many parts of the world. Commercial and population
pressures have led to large areas being converted to agricultural use, though it is difficult to sustain because
of poor soil fertility. As well as removal of timber and species, the clearance of forest has many
environmental impacts at the local, regional and perhaps even global scales. The problem of managing
the tropical forests in those areas where they survive is becoming a global concern. Countries want to
maximize the utilization of their natural resources, but they need to be sustained for the future. How this
can best be done has yet to be resolved.
