The west coast evergreen forests are characterized by the bewildering multiplicity of life forms and overpowering preponderance of greenness. The forest is lofty, dense and characterized by heavy species density. The top canopy is almost unbroken comprised of tall trees, 45m or even more in height with a luxuriant growth of evergreen trees of different sizes and shapes arranged in serial tiers. Above the ground layer of herbs and shrubs, the crown of the trees form three or more super imposed stories, but strata of trees are sometimes never clearly defined as they are continuously growing. The crown of trees in each storey has a distinguished shape. In the top storey the trees are usually umbrella-shaped, in the middle they are more or less candle flame-shaped and are markedly conical at the bottom. Buttressed roots are characteristic in this type. The following species exhibit buttress formation, e.g. Elaeocarpus tuberculata, Cullenia exarillata, Palaquium ellipticum, Poeciloneuron indicum. The boles are long, cylindrical, with thin, smooth barks. The leaves are thick and glossy, rarely finely pinnate or hairy and are very often white or pink when young. Another feature of this type of forest is the phenomena of cauliflory. The presence of Cullenia exarillata, Poeciloneuron indicum and the high proportion of Mesua, Calophyllum, etc. indicate that west coast tropical evergreen forest of this sanctuary belongs to high level evergreen forest of Chandrasekharan (1962 a,b&c). Cullenia exarillata and Poeciloneuron indicum are exclusively limited to this type. The most noticeable difference from the low evergreen forest is the high percentage of occurrence of above species when the precipitation is particularly heavy or the soil moisture particularly favourable.
This forest type is the major vegetation in the sanctuary and it is found at Rosemala, Kallar-Pandimotta, along the banks of Umayar and Uruliyar.
Trees in the upper storey are Dipterocarpus indicus, Calophyllum polyanthum, Mesua ferrea, Poeciloneuron indicum, Mangifera indica, Cullenia exarillata, Vateria indica, Artocarpus heterophyllus, Gluta travancorica, Hopea parviflora, Hopea racophloea, Lophopetalum wightianum, Kingiodendron pinnatum, Dysoxylum malabaricum, Diospyros ghatensis, Palaquium ellipticum, etc.
The trees of middle storey are Garcinia spicata, Polyalthia coffeoides, Elaeocarpus serratum, Fahrenheitia ceylanica, Aglaia lawii, Drypetes elata, Garcinia gummi-gutta, Buchanania lanceolata, Syzygium gardneri, Gordonia obtuse, Aglaia barberi, A. perviridis, Xylopia parvifolia, Aphanamixis polystachya, Humboldtia decurrens, Hydnocarpus alpinia, etc.
The lower storey comprises of Goniothalamus rhynchantherus, Miliusa wightiana, Meiogyne ramarowii, Orophea uniflora, Erythroxylum lanceolatum, Acronychia pedunculata, Aglaia simplicifolia, etc.
The shrubby plants are mostly Dichapetalum gelonioides, Strobilanthus ssp., Lasianthus ssp., Glycosmis macrocarpa, Alpinia malaccensis, Leptonychia caudate, Clausena austroindica, Phaeanthus malabarica, Popowia beddomea, Tabernaemontana gamblei, etc.