Broadleaved forests

Littoral Forest

The littoral zone in the Cook Islands, where not pre-empted by human modification, includes coastal forests dominated by some combination of the trees Barringtonia asiatica , Calophyllum inophyllum , Cordia subcordata , Guettarda speciosa , Hernandia nymphaeifolia , Hibiscus tiliaceus , Pandanus tectorius , Pisonia grandis , Sophora tomentosa , Timonius polygamus and Tournefortia argentea , and the shrubs Morinda citrifolia , Pemphis acidula , Pipturus argenteus , Scaevola taccada , Schleinitzia insularum and Suriana maritima .

Montane Rain Forest

On Rarotonga, excellent examples of relatively undisturbed rain forest, ranging from a lower limit of 50 to 200 m elevation, can be found above the mostly disturbed lowland vegetation. Two primary types can be distinguished.

  • Homalium Forest: On generally steep inland mountain slopes between 30 and 350 m elevation is found a 10 to 15 m tall closed-canopy forest dominated by Homalium acuminatum , but also including Cyclophyllum barbatum , Elaeocarpus tonganus and Ixora bracteata and less frequently Bischofia javanica , Fitchia speciosa , Macaranga harveyana , Pouteria grayana , Terminalia glabrata and Weinmannia rarotongensis .
  • Fagraea-Fitchia Forest: Narrow, exposed, windswept ridges below 500 m with shallow, rocky soils are dominated by a dense cover of large shrubs or small trees of Fagraea berteroana and Fitchia speciosa . The extensive, sturdy root system of Fagraea and sturdy prop roots of Fitchia aid in deterring erosion of the narrow ridges. Associated woody species include Alyxia elliptica , Cyclophyllum barbatum , Coprosma laevigata , Hibiscus tiliaceus , Homalium acuminatum , Meryta pauciflora and Metrosideros collina.
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Cloud Forest

On windy, cloud-covered ridges and peaks on Rarotonga, generally above 350 m, exists a gnarled, moss- and fern-covered forest dominated by Metrosideros collina up to 8 m tall. In higher, wetter spots, Ascarina diffusa becomes dominant. Woody associates include Coprosma laevigata, Elaeocarpus tonganus, Fitchia speciosa, Geniostoma rarotongensis, Morinda forsteri, Pittosporum arborescens, Xylosma gracile, Vaccinium cereum and Weinmannia samoensis.

Makatea Forest

The vegetation on makatea surfaces is generally well preserved because the rough surface is unsuitable for cultivation or human habitation. Examples can be seen on the islands Atiu, Mangaia, Ma?uke, and Miti?aro. The vegetation becomes more species-rich with distance inland.

The coastal makatea forest changes with distance inland from a combination of Cocos nucifera, Hernandia nymphaeifolia, Hibiscus tiliaceus, and Pandanus tectorius, with occasional Barringtonia asiatica and Casuarina equisetifolia, to a tree assemblage in which Elaeocarpus tonganus, Guettarda speciosa, Pisonia grandis, Schleinitzia insularum and Sophora tomentosa become dominant. Fronting the forest is a shrub layer dominated by Scaevola taccada, with Euphorbia atoto, Timonius polygamus and Wollastonia biflora. Pemphis acidula forms a narrow belt closest to the coast.

The inland makatea includes all of the woody species from the coastal makatea except Pemphis acidula, and includes in addition trees of Aleurites moluccana, Calophyllum inophyllum and Hernandia moerenhoutiana that form a higher canopy. Other woody species include Cyclophyllum barbatum, Ficus prolixa, F. tinctoria, Glochidion sp., Morinda citrifolia and Pipturus argenteus.

last updated: Monday, January 12, 2004