Background:-

High temperature and abundant rainfall in the equatorial regions support a luxuriant type of vegetation-the tropical rain forest. In the Amazon lowlands, the forest is so dense and so complete in its vegetational extravagance that a special term ‘selvas’ is used.

Main features of equatorial vegetation:-

Vertical layer arrangement:-

• From the air, the tropical rain forest appears like a thick canopy of foliage, broken only where it is crossed by large rivers or cleared for cultivation. All plants struggle up­wards for sunlight resulting in a peculiar layer arrangement. The tallest trees attain a height of over 150 feet
• Their slender trunks pierce skywards with wide-spread branches at the top. The smaller trees beneath form the next layer, and the ground is rooted with ferns and herbaceous plants which can tolerate shade. Because the trees cut out most of the sunlight the undergrowth is not dense

Great Variety of Vegetation:

• The equatorial vegetation comprises a multitude of evergreen trees that yield tropical hardwood, e.g. mahogany, ebony, greenheart, cabinet woods and dyewoods.
• There are smaller palm trees, climbing plants like the lianas or rattan which may be hundreds of feet long and epiphytic and parasitic plants that live on other plants. Under the trees grow a wide variety of ferns, orchids and lalang

Multiple Species:

• Unlike the temperate forests, where only a few species occur in a particular area, the trees of the tropical rain forests are not found in pure stands of a single species. It has been esti­mated that in the Malaysian jungle as many as 200 species of trees may be found in an acre of forest.

Forest Clearings:

• Many parts of the virgin tropical rain forests have been cleared either for lumbering or shifting cultivation. When these clear­ings are abandoned, less luxuriant secondary forests, called belukar in Malaysia, spring up. These are characterized by short trees and very dense under­growth. In the coastal areas and brackish swamps, mangrove forests thrive.

Why tropical countries are net timber importers:-

• Many species are found in a smaller area. For example Malaysian jungles have around 200 species in a acre of forest land. Hence, commercial exploitation of trees becomes difficult.
• This has made commercial exploitation of tropical timber a most difficult task. Many of the tropical hardwoods do not float readily on water and this makes haulage an expensive matter. It is therefore not surprising that many tropical countries are net timber importers.
• In tropical areas some tree-species are extremely valuable, but they are scattered. This heterogeneous supply of timber leads to cost of gathering very high.
• Valuable trees are scattered throughout jungle, you need some land transport before logs reach the rivers. But road construction is difficult due to rain, dense vegetation.
• Poor quality of secondary vegetation