Included here are the mountains of Sumatra. The high Barisan Mountains run northwest-southeast for some 1600 km reaching a height of 3800 m at Mount Kerinci.

Sumatran Rhododendron-Vaccinium Alpine Scrub

Above an altitude of about 3000 m most trees give way to a dense ericaceous scrub characterized by Rhododendron retusum and the endemic Vaccinium miquelii (Ericaceae).  There are also many other endemic ericoids including Diplycosia atjehensis, D. glauciflora, D. sumatrensis, Gaultheria acroleia, G. atjehensis, G. kemiriense, Rhododendron adinophyllum, R. aequabile and R. sumatranum, while other endemic shrubs or small trees include Lithocarpus atjehensis (Fagaceae) and Symplocos sumatrana (Symplocaceae). One of the last trees to peter out is Myrica javanica but at these altidudes it grows no more than about 8 m high. The ground layer consists of tussocky species like Carex hypsophyla and Gahnia javanica and occasional herbs such as Anaphalis javanica and the two endemic species Pyrola sumatranum (Pyrolaceae) and Senecio sumatrana (Asteraceae). Ferns, such as Dicranopteris pubigera, Gleichenia volubilis and Hypolepis punctata, are also present.

References

Laumonier, Y. 1997. The Vegetation and Physiography of Sumatra. Kluwer Academic Press.

Ohsawa, M., Nainggolan, P. H. J., Tanaka, N. & Anwar, C. 1985. Altitudinal zonation of forest vegetation on Mount Kerinci, Sumatra: with comparisons to zonation in temperate regions of East Asia. Journal of Tropical Ecology, 1: 193-216.

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, T., Damanik, S. J., Anwar, J. & Hisyam, N. 2000. The Ecology of Sumatra. Periplus.