in Sri Lanka - Ministry of Environment

Present Status of Montane Forests in Sri LankaSiril WijesundaraDepartment of National Botanic Gardens Peradeniya.siril.wijesundara@gmail.comIn Sri Lanka the montane forests, also known as upper montane forests, occur at elevationsbeyond 1500 m above mean sea level. They share an average temperature of about 16degrees Celsius and rainfall of above 2000 mm without any marked dry periods, and humidityabove 80%.It is characterized by a short canopy of about 13 m, with a dense shrub layer of about 3-4m. Gnarled and twisted trees with rounded (umbrella-shaped) crowns with tiny, leathery leavesto accommodate the strong winds that prevail. High density of epiphytes, epiphylls, mosses,bryophytes and lichens are commonly found. Soils are red-yellow podzols. Keena (Calophyllumwalkeri), Damba (Syzygium revolutum) and S. rotundifolium make the abundant tree specieswith Wal sapu (Magnolia nilagrica), Mihiriya (Gordonia ceylanica). Gregariously flowering Nelu(Strobilanthes spp.) form a prominent shrub layer, while Usnea (Old man’s beard) is a distinctlichen; epiphytic orchids such as Eria bicolor, Robiquetia brevifolia, and filmy ferns are common;Sudu Binara (Exacum walkeri) is a distinct herbaceous flower. Pigmy forests or elfin forests arefound on top of Hakgala, Totapola and Knuckles, made of stunted trees of Ilex, Eurya, Syzygiumand shrubs such as Rhodomyrtus, Osbeckia, and Hedyotes (Wijesundara, 1991)Montane forests once formed a more or less continuous cover or cap extending over almostthe entire third peneplain of Sri Lanka, encompassing the Pedro, Totapola and Adam’s peakranges, and the isolated Knuckles range (de Rosayro, 1946). At present only 3000 ha ofmontane forests are left in the island. In addition to their role in water retention and releasein catchment areas in this country, montane forests are also the home of about 500 endemicplant species which constitute about 50% of all the endemics in Sri Lanka (Peeris, 1975).Trees in the montane forests are covered with mosses and lichens enabling them to interceptmist effectively. According to some hydrological studies done, 25% of the precipitation receivedby the montane forests in Horton Plains is due to mist interception (Gunawardena et al, 1998).Despite their biological and hydrological importance, vast areas of these montane forests havebeen cleared during the latter part of the 19th century for introduction of plantation crops suchas tea. Only about 3,100 ha of montane forests are remaining at present (MENR, 2009).Flora and origin of the montane zoneMore than half the species of our montane zone are endemic to it and not found in Nilgiri orother hills of the Indian peninsula. However, about 20 species and 44 genera are commonto the South Indian and Sri Lankan hills (Blasco, 1971). There is not a single genus endemicto the hills of either country or both combined, and the flora of Indo-Sri Lankan high lands isconsidered as a southward extension of the Himalayan flora.Dr. J. C. Willis, a former Director of Royal Botanic Gardens, Peradeniya (1896-1912), analyzedthe hill top floras of Sri Lanka and supposed that the high degree of endemism in the montanezone was due to isolation (Willis, 1908). He tabulated the proportion of hill top species with181