The KDN complex is situated in the southern part of Sri Lanka, which is about 147km away from Colombo. The total forest is spread over 10,139.3 hectares. The forest complex occupies the interfluves between two rivers, the Gin Ganga and the Nilwala Ganga, and consists of a series of ridges and valleys, with elevation ranges from 60m to 425m above mean sea level. The mean monthly temperature is around 27C with a diurnal range of 4-5C, with maximum temperature recorded in mid-May. The annual rainfall in Kanneliya is around 3750mm.
The Kanneliya Forest as a whole is among the most important natural forests in the southern province for protection of the head waters of the Gin and Nilwala, which are critically important for socio-economic development in the Galle and Matara districts. This region is identified as floristically one of the richest areas in South Asia. There is a high proportion of endemism among the identified woody plants, with 159 species belonging to 94 genera and 41 families being endemic to Sri Lanka. Some 220 faunal species with 41 endemics have been recorded from the KDN and adjacent forests. A majority of the 20 endemic birds in Sri Lanka are restricted to the rain forests of the southwest. Large numbers of medicinal plants are found in the KDN forest complex. Some of these plants are:
• Weniwelgata – Concinium fenestratum
• Kudahedaya – Lycopodium Squarrosum
• Maha hedaya – Lycopodium phlegmaria
• Kothala Himbutu – Salacia reticulate
• Rasakinda – Tinopora cordifolia
From journal Kanneliya-Dediyagala-Nakiyadeniya Forest Complex