Included here are forests of Sulawesi (formerly Celebes) and its neighbouring islands.

Sulawesian Lower Montane Forest

Dominated by chestnut, such as Castanopsis acuminatissima, and oaks, such as the endemic Lithocarpus celebicum (Fagaceae), these forests range in altitude from about 1500 to 2400 m, and can be found on mountains such as Lompobatang, Roroka Timbu and Tambusisi. Their canopies reach heights of over 30 m and normally include a sub-canopy of smaller trees. Other broad leaf trees include Acer caesium and the endemic Macadamia hildebrandii (Proteaceae), and conifers such as Agathis dammara, Dacrycarpus steupi, Dacrydium nidulum, Phyllocladus hypophyllus and Podocarpus neriifolius. In the undergrowth rattans and tree ferns are well represented. In fact, tree ferns reach their peak of diversity in these forest with species such as Culcita villosa, Dicksonia blumei, Cyathea oosora, C. oinops and several endemics like Cyathea dimorpha (Mt Bohaa), C. inquinans (Mt Lompobatang), C. pallidipaleata (Mt Rantemario), C. saccata (Mt Topapu) and C. sarasinorum (Mt Sibaronga). Epiphytes including many orchids and ferns are common. Among the ferns, the endemic Lindsaea pulchella (Lindsaeaceae) is unusual in being exclusively associated with tree ferns. Sulawesi also appears to be the evolutionary centre for the epiphytic fern genus Lecanopteris with more species found here than anywhere else. Most of the endemic species like Lecanopteris balgooyi, L. carnosa, L. celebica, L. darnaedii, L. holttumii and L. spinosa are confined to the montane forests. But these ferns have a unique distinction as possibly being the only ant-ferns on the planet. They have a large, multi-chambered rhizome in which ants live. The ferns benefit from the mineral materials deposited in the chambers in the form of dead bodies, faeces and discarded food.

Sulawesian Upper Montane (Mossy) Forest

Ranging in altitude from about 2400 to 3000 m these forests are mainly characterized by species of the Ericaceae with many colourful rhododendrons, bilberries (Vaccinium) and wintergreens (Gaultheria). The canopy can reach heights of 18 m but is often much lower. Of the 24 rhododendrons known on Sulawesi, 21 are endemic, and include several small trees like Rhododendron impositum and R. pudorinum. Vaccinium is represented by 16 species, of which 13 are endemic and again include several small trees like Vaccinium latissimum and V. warburgii.  Of Gaultheria only 2 shrubby species are known, G. celebica and G. viridflora, both of which are endemic. The lesser-known ericoid genus Diplycosia is also well represented with all its 17 known species endemic to this BioProvince including various shrubs such as Diplycosia celebica. Epiphytic shrubs are also characteristic and with the exception of Gaultheria, all the above-mentioned ericoid genera include epiphytic representatives such the endemic Dipycosa aperta, Rhododendron celebicum and Vaccinium henrici. Other endemic trees include various species of Elaeocarpus such as E. gambutanus, E. lancistipulats and E. linnaei (Elaeocarpaceae), all found in the upper montane forest in the Dumoga Bone National Park. As the name of these forests suggest, one of the most characteristic features, especially in the wetter areas, is the abundance of mosses and liverworts.  The so-called beard ‘moss’ (Usnea), which is actually a lichen, is also frequently encountered. In fact, garlands of beard-moss and the proper moss Aerobryum can be seen hanging from many branches. A ground level the giant mosses Dawsonia and Spiridens may be encountered together with ferns and pitcher plants, while among the endemic herbaceous plants is Trachymene erodioides (Apiaceae).

References

Leith, H. & Werger, M. J. A. 1989. Ecosystems of the World 14B - Tropical Rain Forests. Elsevier Scientific Publishing Company.

Meijer, W. 1976. Botanical Explorations in Celebes and Bali. National Geographic Society Research Reports, 60: 583-605.

Milliken, W. & Proctor, J. 1999. Montane forest in the Dumoga Bone National Park, Northern Sulawesi. Edinburgh Journal of Botany, 56: 449-458.

Steenis, C. G. G. J. van. 1957. Outline of the vegetation types in Indonesia and some adjacent regions. Proceedings of the Pacific Scientific Congress, 8: 61-97.

Whitten, A. J., Mustafa, M. & Henderson, G. S. 1987. The Ecology of Sulawesi. Gadjah Mada University Press.