RAIN-FOREST VEGETATION OF EUA ISLAND, KINGDOM-OF-TONGA

The indigenous vegetation of 'Eua Island, Tonga, is described and a sp ecies list presented. Quantitative data were collected from 40 forest plots in which all vascular plant species were recorded and the diamet ers of all stems greater than or equal to 5 cm dbh were measured. Plot classification, based on basal area data, identified six forest types , two coastal and four inland, which reflect an elevational sequence f rom the coast to the island's summit (312 m a.s.l.). A polar ordinatio n, based on basal area data, arranged plots from the four inland fores t types in a sequence from low to high elevation along one ordination axis, and from more mature to less mature along a second axis. Species richness increased with elevation. Several additional, non-forest veg etation types, including fern- and grass-dominated vegetation of inlan d ridges and shrub-dominated vegetation of cliffs and rocky shores, we re sampled semi-quantitatively and are also described.