Sinharaja forest reserve is one of the least disturbed and biologically unique rain forests in Sri lanka. Pocketed between two sizeable rivers, namely river Kalu Ganga from the north & river Gin ganga from the south, of the numerous rivers of this paradise like Island is a virgin tropical rainforest of enormous national significance. This forest covers an extent of about 11187 hectares from east to west for almost 30 km across the southwest lowland Wet Zone of the island at the southern edges of the hill country, enveloping a series of switchback hills, ridges & valleys ranging in altitude from 300m up to 1170m with a breadth of 3.7 km north to south. Beautiful Streams, springs, rivers, waterfalls, leopard, monkeys, butterflies and moths, rare trees, valuable shrubs and medicinal herbs are all found within its green canopy. A trek along the sinharaja paths would provide nature enthusiast a never to be forgotten experience of sights and sounds and feelingsApart from its ecological and biodiversity value its scenic beauty is also invaluable. The largest known tree of the country is found in the Sinharaja, which is an endemic tree. Insect eating Pitcher plant is frequently seen here. This magnificent rainforest is also a home for large number of butterflies. In side the forest is dark even during the day time due to close canopy above and one can here the voice of cicadas and frogs throughout the time. Small streams found within the forest contain crystal-clear cool water and one can clearly see the fish, toads and crabs swimming in it. It was declared a National wilderness area in 1988 and lately a world heritage site in 1989.Tropical Wet Evergreen ForestThe vegetation of Sinharaja may be described either as a Tropical Lowland Rain Forest or Tropical Wet Evergreen Forest. A few notable characteristics of the forest are the loftiness of the dominant trees, the straightness of their bole, the abundance of regeneration and the diversity of species. The average height of the trees varies between 35m to 40m with some individuals rising even up to 50m.The undergrowth is seldom dense; dense scrub growth does occur on rock shelves or gaps on the canopy created by falling of mature trees. The great diversity of species of Sinharja forest makes it difficult to distinguish ecological patterns. However, some tree associations have been recognized and these are the Dipterocarpus (Hora-Bu Hora), confined to the lower elevations along the Gin Ganga valley, and the Mesua-Doona (Shorea) in the well drained lower ridge areas. This association forms the matrix of the Forest.The vegetation found here is that of humid wet evergreen forest type with a high degree of endemism. Some families show an endemism of more than 90%. The untapped genetic potential of Sinhara flora is enormous. Out of the 211 woody trees and lianas so far identified within the reserve, 139 (66%) are endemic. Similarly, high levels of endemism are true for the lower plants like ferns and epiphyts. Out of the 25 general endemic species found in Sri Lanka, 13 are represented in Sinharaja.The total vegetation density, including trees, shrubs, herbs and seedlings, has been estimated to be around 240,000 individuals per hectare. Of this, 95% comprise individuals of the ground layer below 1m in height.Mammals & ButterfliesThe reserve's most common mammal is the purple-faced langur monkey, while you might also encounter three species of squirrel - the dusky - striped jungle squirrel, flame-striped jungle squirrel & western giant squirrel-along with mongoose. More than half of Sri Lanka's mammals & butterflies have been recorded here. Having said that we must hasten to add that in the dense forest animals can be hard to see. The purple-faced langur monkey is the most commonly seen mammals. There are three species of squirrels. The dusky-striped jungle squirrel, flame-striped jungle squirrel & western giant squirrel. And others include mongooses, sambar, leopards, rusty spotted cats, fishing cats & civets. Porcupines & Pangolins waddle around the forest floor.Bird populationSinharaja has one of Sri Lanka's richest bird populations: 21 of the country's 26 endemic species have been recorded here. Unfortunately the density of the forest & the fact that its birds largely inhabit the topmost part of the canopy means that actually seeing is extremely difficult, & probably beyond the patience of all but committed birders-the tantalizing chirrupings of myriad invisible birds are an inevitable accompaniment to any visit to the reserve. It's much easier to spot birds around the edges of the forest, in the agricultural lands, which bound the park. Rare endemics include red-faced Malkoha, Sri Lanka blue magpie, the white-headed starling, green billed coucal, orange minivets, orioles, white throated kingfishers, Indian pond herons, spotted doves, babblers & many others. Pedestrian Ceylon jungle fowl found here is a more colourful version of & relative to the domesticchicken. An interesting & colourful spectacle is the presence of mixed flocks, sometimes comprising up to 80 species.The rich reptile populationThe agamid are the best represented group of reptiles, and of these the most common is the Green Garden Lizard. A rare sighting and one of special significance is the Calotes liolepis, and arboreal species and the rarest of all agamid found in the island. The only tortoise recorded in the reserve is the Hard-shelled Terrapin, while of the species of skinks; the Spotted Skink can often be seen. Of the snakes, the Green Pit viper and Hump-nosed Viper are commonly found in this forest and are endemic to Sri Lanka.