Equatorial rain forests consist of tall closely set trees whose crowns form a continuous canopy of foliage and provide dense shade for the ground and lower layers. Tree leaves are broad and evergreen and the crowns tend to form into two or three layers, of which the highest layer consists of scattered emergent crowns rising to 40 m. Typical of the equatorial rain forest are lianas, thick woody vines supported by the trunks and branches of the trees. Some are slender like ropes, others reach thicknesses of 20 cm.

Epiphytes are numerous using the trunk, branches or foliage of trees and lianas solely as a means of physical support. They are of many plant classes and include ferns, orchids, mosses and lichens. Some epiphytes are stranglers, sending down their roots to the soil, eventually surrounding the tree and ultimately replacing it.

An important characteristic of the equatorial rain forest is the large number of trees that coexist. As many as 3000 species may be found in 1 square kilometre. The floor of the forest is usally so densely shaded that plant foliage is sparse close to the ground and gives the forest an open aspect, making it easy to traverse. The ground surface is covered only by a thin litter of leaves. Rapid consumption of dead plant matter by bacterial action results in the absence of humus in the soil.

Equatorial rain forests are limited to the Amazon basin, the Congo lowland and the South East Asian islands of Sumatra, Borneo and New Guinea.

From 10º latitude North and South to the tropics of Cancer and Capricorn equatorial rain forest is substituted by tropical rain forest along windward coasts. Here we find a distinct annual precipitation and temperature cycle, resulting in fewer species and lianas. Epiphytes are, however, abundant due to continued exposure to humid air and cloudiness of the coastal hills and mountain slopes. Tropical rain forest is typical for the Carribian lands, the eastern coasts of Brazil and Madagascar and the western coasts of India, Burma and Thailand.

Monsoon forests present a more open tree growth than the equatorial and tropical rain forests. Consequently, there is less competition among trees for light but a greater development in the lower layers. Trees have massive trunks with thick and rough bark reaching a height of only 35 m.

The most important feature is the deciduousness of most of the tree species, with the teakwood tree (Tectona grandis) being the most important one among them. This is a response to a climate where a long rainy season alternates with a dry and cool season. Typical monsoon forests cover inland Burma, northern Thailand, Laos and Cambodia.

Where the forest has been cleared by cutting and burning, the returning plant growth is low and dense and may be described as jungle. It can consist of of a tangled growth of lianas, bamboo scrub, thorny palms and thickly branching shrubs, constituing an impenetrable barrier to travel in contrast to the open area of the rain forest.