This type of forest is considered the climax vegetation of the tropical region and is found usually at elevations between 240 m to 1100 m and may extend sometimes even up to 1350 m with some variation in floristic composition. One of the outstanding features of the West Coast Tropical Evergreen Forest is the presence of an overwhelming majority of the plants which are woody and of large dimensions. Its vegetation consists of at least three tiers, the highest often attaining a height of 40 to 45 m. Very often the trees are buttressed at the base and the boles are clean, cylindrical, un-branched at least up to two-thirds of their height and generally with a spreading or umbrella shaped crown at the top. The middle stratum is more or less candle shaped and the lower characteristically conical. The trees are normally with orchids, aroids, mosses, ferns and lichens. Species with cauliflory are not common.

Not only the trees but the climbers and epiphytes are also woody. The under growth largely consists of woody plants, seedlings, shrubs and young woody climbers. Trees with barks showing various features like smooth, flaky, fissured etc. are not uncommon. The multiplicity of species co-existing in complex biological equilibrium gives this type of forest the highest status, the ‘climatic climax’. The evergreen forests are met with in the Karinganni, Pulikan-chandupulan area and upper reaches of Pannikkottur and Pilla Peruvanna malavaram. The evergreen species is also seen mixed with deciduous species (Eg: Terminalia bellerica) without affecting the evergreen nature of the forest as a whole. The canopy is dense and closed. The trees in this forest are tall cylindrical poles with closed canopy and stratification, a characteristic growth pattern in tropical evergreen vegetation. But as one proceeds towards ridges and hill tops, the stem becomes less and less clean and the canopy stratification is less conspicuous.

Climbers are abundant along the banks of water courses and are less abundant where canopy is closed. The commonest species of climbers are Entada rheedei, Gnetum scandens, Acacia pennata, Dioscorea sp and Connarus sp. In flat and very rapid drained areas, cane brakes of varying density are found.

The common terrestrial ferns which range from the hydrophilous forms to small xerophilous ones are found in Malabar wildlife sanctuary. They are generally of the genera Alsophyla. Epiphytic vegetation, mosses and lichens, of the tropical evergreen forests is abundant. Orchids with thick water storing roots are common but not as frequent as the ferns.
The common concept is that the Tropical Evergreen Forest represent a climax stage without any retrogression or progressive change or in other words is fairly stable. The tropical evergreen forests of this sanctuary has to be viewed as the most probable population that could exist under given ecological factors like climate, soil, site-factors, availability of species and their characteristics. Based on the study conducted for the working plan, taking into account the characteristics of species, it could be seen that most of the species occupying the Ist storey are of evergreen character. But the deciduous species like Terminalia bellerica are also seen in upper canopy. The IInd storey of the vegetation is with predominantly evergreen species. However, species like Terminalia chebula, Emblica officinalis, Pterocarpus marsupium, Stereospermum chelonoides, Lannea coromandelica, Grewia tiliifolia, Dillenia pentagyna and Cassia fistula which are of deciduous nature are also present.
The floristic composition of the tropical evergreen forest is given table below: