Included here are the Caroline Islands, Mariana Islands, Marshall Islands, Gilbert Islands, Ellice Islands, Phoenix Islands, Tokelau Islands, Baker Island, Banaba Island, Howland Island, Nauru Island and Wake Island.

Micronesian Montane Cloud Forest

Botanically these dripping, soggy forests are some of the most interesting vegetation types of tropical islands with their gnarled, stunted trees covered in mosses and liverworts. In Micronesia cloud forest is confined to Pohnpei (Ponape) and Kosrae (Kusaie) in the Caroline Islands. On Pohnpei it is limited to a few hectares on the island’s summit, Mt Nahnalaud (772 m), where rainfall exceeds 5000 mm/year and ground level orographic clouds shroud the area on a daily basis. The forest canopy can be as low as 6 m, but canopy emergents can tower up to 25 m. The typical species are largely endemic and include Maesa carolinensis (Myrsinaceae), the palm Clinostigma ponapensis (Arecaceae), and the tree fern Cyathea ponapeana (Cyatheaceae), while on the more rocky terrains the endemic Astronidium ponapensis (Melastomataceae) and Garcinia ponapensis (Hypericaceae) predominate. The summit also includes several almost pure stands of the endemic Pandanus patina (Pandanaceae), which is frequently covered in the endemic liana Freycinetia ponapensis (Pandanaceae). Other common endemics include Cyrtandra urvillei (Gesneraceae) and Syzygium carolinese (Myrtaceae). On Kosrae the main canopy species include three ferns (Cyathea) and the endemic Astronidium kusaianum (Melastomataceae) and Elaeocarpus carolinensis (Elaeocarpaceae), while other common endemics include Cinnamomum carolense (Lauraceae) and Ptychosperma kusaiensis (Arecaceae). In the lower canopy Eugenia stelechanthoides and Polyscias subcapitata are common, while the many epiphytes include the endemic Elaphoglossum carolinense (Elaphoglossaceae) and Peperomia kusaiensis (Piperaceae).

References

Endress, B. A. 2002. The importance of endemic species to forest succession in Palau. Micromesica, 34: 141-153.

Fosberg, F. R. 1960. The vegetation of Micronesia. Bulletin of the American Museum of Natural History, 119: 1-75.

Fosberg, F. R., Sachet, M. H. & Oliver, R. 1979. A Geographical Checklist of the Micronesian Dicotyledonae. Micronesica, 15: 41-295.

Fosberg, F. R. 1984. Phytogeographic comparison of Polynesia and Micronesia. In: Biogeography of the Tropical Pacific (Proceedings of a Symposium). Eds. F. J. Radovsky, P. H. Raven and H. Sohmer. Bishop Museum Special Publication No. 72.

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

Merlin, M. D. & Juvik, J. O. 1995. Montane cloud forest in the tropical Pacific: some aspects of their floristics, biogeography, ecology, and conservation. In: Tropical Montane Cloud Forests. Eds.  L. S. Hamilton, J. O. Juvik and F. N. Scatena. Ecological Studies 10. Springer-Varlag.

Mueller-Dombois, D. & Fosberg, F. R. 1998. Vegetation of the Tropical Pacific Islands. Springer.

Schmid, M. 1989. The forests in the tropical Pacific archipelagoes. In: Ecosystems of the World 14B - Tropical Rain Forest Ecosystems.  Elsevier.

Stone, B. C. 1970-71. The Flora of Guam. Micronesica, 6: 1-659.