M. collina was formerly thought to have a larger range, extending to Vanuatu, Fiji, and the Samoan Islands.

[2] In the Society Islands, Metrosideros collina is a common canopy tree in montane rain forests above 300 meters elevation, and in cloud forests from 400 to 1000 meters elevation, and on exposed ridges.

M. collina and associated trees, including Pterophylla samoensis, Elaeocarpus floridanus, and Pittosporum rarotongense, form a low forest canopy averaging eight meters tall.

In wetter areas and at higher elevations Ascarina diffusa is often co-dominant or dominant in the canopy.

[5] Metrosideros collina is a common canopy tree in higher-elevation interior forests on Pitcairn Island, with the trees Homalium mouo, Ficus prolixa, Pandanus tectorius, and Thespesia populnea.