This type of forests is found in areas wherever humidity and soil moisture conditions are favourable, rainfall is 1500-5000mm or more and altitude is 250 to 1200m. The main forests of this type are found in the Orukomban range and they fall under the core zone of this sanctuary. These evergreen forests are contiguous with the evergreen forests of adjoining forest divisions of Chalakkudy and Nemmara.

Karimala is another important region, where evergreens meet with grasslands. At Pooppara, it is in continuation of the evergreen forests of the Vazhachal forest division. Small patches of the evergreen trees are also found within the moist deciduous localities such as Parambikulam, Vengoli, Karianshola and Pulickal areas. Total extent of these forests is about 50 sq. km, normally seen at 800 m above mean sea level in this sanctuary.

Evergreen forests exhibit luxuriant growth, and closed canopy of trees and woody climbers. High humidity, shade and sheltered conditions provide ideal habitat for epiphytes as well as terrestrial orchids, ferns, mosses and other herbaceous flowering plants. The quantity of epiphytes and mosses tend to increase with the increase in altitude, while the number of woody climbers decrease. The main character of these evergreen trees is to develop buttresses at the base of the bole. In addition to these, many streams are originating from these forests.

In these forests, the trees with varying heights show stratification. There is dominance of certain species in the upper stratum. The important associations noticed are, as under:

Canopy wise Species Distribution