Sri Lankan Lower Montane Rainforest

These forests form a zone between 600 and 1500 m around the central hills and see their best development in the Knuckles Range and in the central part of the Great Escarpment. In some respects they are transitional between the lowland and upland rain forest but some species including endemic trees such as Calophyllum tomentosum (Hypericaceae), Cinnamomum citrodorum, Cryptocarya wightiana, Litsea gardneri (Lauraceae) and Elaeocarpus glandulifer (Elaeocarpaceae) are more characteristic of montane forest. In general their species richness is slightly lower than the lowland forests and their structure, with just three layers, is less complex. The canopy, which reaches heights of 80 feet, typically comprises Calophyllum soulattri, Carallia calycina, Doona gardneri, Durio zeylanicus, Garcinia echinocarpa, Meliosma arnottiana, Nothopegia beddomei, Semecarpus nigro-viridis and endemic species such as Calophyllum cuneifolium, C. tomentosum (Hypericaceae), Doona gardneri (Dipterocarpaceae), Elaeocarpus glandulifer (Elaeocarpaceae) and two endemic palms Loxococcus rupicola and Oncosperma fasciculatum (Arecaceae). In fact, the endemic dipterocarp Doona gardneri can be one of the most prominent species of these forests. In a lower arborescent storey the main species are Acronychia peduculata, Actinodaphne ambigua, Amoora rohituka, Celtis cinnamomea, Cleidon nitidum, Dovyalis hebecarpa, Eleocarpus amoenus, Euodia roxburghiana, Helica zeylanicus, Lagerstroemea speciosa, Ligustrum walkeri, Meliosma simplicifolia, Machilus macrantha, Meloechia umbillata, Microtropis wallichiana, Nelitris jambosella, Neolitsea involucrata, Ouratea zeylanica, Ocophea zeylanica, Schefflera wallichiana, Villebrunea integrifolia, while endemics at this level include species such as Aporosa fusiformis (Euphorbiaceae) and Elaeocarpus subvillosus (Elaeocarpaceae). Despite having a lower overall species diversity, these forests support much greater numbers of epiphytes, and these are particularly rich in orchids such as Adrorhizon purpurescens, Dendrobium panduratum, Eria braccata, Josephia lanceolata and Oberonia longibracteata. The field layer typically includes Allophylus cobbe, Clerodendron infortunatum, Elettaria involucrata, Mallotus walkerae, Milliusa indica, Ochlandra stridula and Strobilanthes species.

Sri Lankan Highland or Upper Montane Rainforest

These forests, sometimes referred to as tropical montane cloud forests, start at about 1500 m but see their best development above 1800 m, and crown the highest mountains and plateaus of Sri Lanka. The largest single expanse occurs as a crescent extending from Siripada to Pidurutalagala (across the Nuwara, Eliya and Horton plains). Pidurutalagala is the highest peak on the island measuring 2524 m and this is still below the timberline for these forests, and there is no upper conifer zone. Isolated patches can also be found on Knuckles, Namunukula and Haputale. Floristically they are less rich than the forests of lower altitudes, but about 50% of all their species are endemic to Sri Lanka. Their structure is also less complex with all trees more or less arranged in a single layer. Their canopies normally reach heights of about 30 feet but on rare occasions extreme dwarf varieties of these jungles occur reaching no higher than about 3 feet. These so-called pygmy rain forests can be found, for example, on Knuckles Wilderness. Another unusual feature is the lack of conifers and members of the Fagaceae, which normally play an important role in the montane forests of Southeast Asia. Conifers, in particular, often form important emergents, but on Sri Lanka this role is mainly played by endemic species of Calophyllum (Hypericaceae). The frequency of various species of Symplocos (Symplocaceae) is a further peculiarity with all but one of them endemic. The tree layer typically comprises Acronychia pedunculata, Actinodaphne ambigua, Adinandra lasiopetala, Aporosa latifolia, Elaeocarpus montanus, Euonymus rovolutus, Gordonia zeylanica, Litsea ovalifolia, Michelia nilagirica, Microtropis ramiflora, Neolitsea fuscata, Olea polygama, Photinia notoniana, Plectronia montana, Pygeum wightianum, Rhamnus arnottianus, Scolopia crenata, Syzygium revolutum, Symplocos spicata and Terstroemia japonica. While among the many endemic species are Calophyllum walkeri (Hypericaceae), Cinnamomum litsaefolism, Litsea iteodaphne (Lauraceae), Syzygium rotundifolium and S. umbrosum (Myrtaceae). Epyphytes continue to be a major element with many orchids such as Cirrhopetalum odoratissima, Coelogyne odoratissima, Dendrobium aureum, Eria bicolor, Oberonia wightiana and the endemic Ipsea speciosa (Orchidaceae) covering the branches of trees. Mosses and filmy ferns cover many of the tree trunks and lichens hang from twigs. However, there are fewer climbers, but species such as Asparagus falcatus, Elaeagnus latifolia and Toddalia asiatica are often prominent. On the Knuckles range there are a number of rare, endemic species associated with these forests such as Calophyllum trapezifolium (Hypericaceae), Eugenia lucida, E. phylliroides (Myrtaceae) and Stemonoporus affinis (Dipterocarpaceae) that are confined to these mountains. In general the field layer is often densely carpeted with Webera montana, species of Stenosiphonium and dwarf bamboos such as Indocalamus wightianus, Oxytenanthera monodelpha and Teinstachyum attenuatum. Other associated species include Diacalpe aspidioides, Doodia dives Lastraea beddomii, Leptgramme totta, Lomaria patersoni, Muranta fraxinae and Osmunda javonica.

References

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Werner, W. L. 1995. Biogeography and Ecology of the Upper Montane Rain Forest of Sri Lanka (Ceylon). In: Tropical Montane Cloud Forests. Eds.  L. S. Hamilton, J. O. Juvik & F. N. Scatena. Ecological Studies 10. Springer-Varlag.