Most of Venezuela 's vegetation is tropical and nondeciduous or semideciduous, retaining foliage throughout the year or shedding it minimally. Altitude and rainfall variations determine differences in vegetation.
Altitudinal contrasts abound.
True tropical growths do not generally flourish above 1,500 feet, although the selva intermingles with tall savanna grasslands in transitional zones in the interior. The selva gives way to semitropical vegetation, reaching up to about 5,000 feet and characteristically supporting plant life that includes tree ferns and epiphytes, such as orchids. Higher up the Andean slopes, this fern forest gives way to a transitional zone of mountain vegetation, and above 10,000 feet is the p ramo vegetation, which has few trees but a variety of small alpine shrubs and lichens. The drier northwestern coastal area, which was formerly covered with dry scrub woodland and grasses, has suffered from clearing, soil denudation, and overcultivation. Except in the remoter interior, indigenous and introduced species coexist on the forested slopes and around the settled lowland plains and valleys.