Forest Vines to Snow Tussocks: The Story of New Zealand Plants
Although only 400 km long, New Caledonia is composed of continental rocks similar to those of New Zealand and has a rich and, in many ways, remarkable flora. Conifers are particularly prominent with Araucarias, tall and pencil-like or of candelabra form, providing a distinctive character to many landscapes. Indeed, of the 19 species of Araucaria recognised for the world 13 are restricted to New Caledonia. Several species of Agathis (kauri) are also present, several genera of the family Podocarpaceae, including the only known parasitic conifer (Parasitaxus ustus) and 3 species of Libocedrus. Several old southern families of flowering plants are also strongly represented — Myrtaceae, Proteaceae, Epacridaceae, Cunoniaceae. The primitive family Winteraceae is centred in New Caledonia with 4 genera and about 16 species.
For the most part New Caledonia has a quite steep topography, but the mountains up to 1600 m in altitude are not high enough to support alpine vegetation. On the drier west of the island and on burnt sites in the east there are extensive open woodlands of Australian aspect dominated by Melaleuca quinquenervia with its spongy fire-resistant bark. As in Australia, the Melaleuca also grows in swampy sites and it has been suggested that prior to the arrival of human beings it may have been largely restricted to such places, becoming more widespread following destruction of rain forests on better drained sites by fires of human origin.
At lower elevations closed forests which are still intact share many genera with similar forests in Australia and New Guinea and to a lesser degree New Zealand.189 Strangling figs may occur as emergents. In places, particularly on ridge crests, there are also species of Araucaria and Agathis. A number of endemic palms are prominent as are some tree ferns, including Cyathea novaecaledoniae with its distinctive greyish trunks which attain heights of up to 30 m. The ferns Asplenium nidus and Drynaria rigidula are frequent as nest epiphytes.
At higher altitudes the montane rain forests are lower in stature, different in species composition and have more New Zealand links. The strangling figs of lower elevations give way to Metrosideros and the related Carpolepis, some species of which are frequently or occasionally initially page 230epiphytic. Similarly the nest fern epiphytes give way to Astelia novaecaledoniae. Weinmannia and other members of the Cunoniaceae, tree ferns and conifers of the family Podocarpaceae are important components of these forests.
Nothofagus occurs in patches mixed with other genera or in pure ridge crest stands, although not on all mountains. The species of Nothofagus, as in New Guinea, belong to the N. brassii group and some are notable for having unusually large leaves particularly at the juvenile stage (Fig. 70).
The most notable physical feature of New Caledonia as far as the plants are concerned is the unusual extent of ultramafic or 'serpentine' rocks, which occupy a third of the island. Unlike some similar sites elsewhere in the world New Caledonian serpentine supports a rich and distinctive flora190 in which conifers, Nothofagus, and the families Myrtaceae, Proteaceae, Epacridaceae and Casuarinaceae are prominent. Shrub and sedge associations are widespread, but there are also quite dense forests particularly at higher elevations.