Nothofagus starkenborghiorum has a wide distribution across the highlands of New Guinea, extending from the Vogelkop Peninsula in the west across the Central Range to the Papuan Peninsula in the southeast. It is also found in the montane forests of New Britain's highlands. It generally grows in lower montane forest above 1000 meters elevation, but is sometimes found at lower elevations – as low as 610 meters on New Britain, and 700–800 m at Lake Kutubu in Southern Highlands Province of Papua New Guinea.[3]
In lower montane forests it often grows on ridges and on limestone soils. It is typically the dominant canopy tree, or forms monodominant stands in mixed montane forests, and less often grows in mixed species forests. Nothofagus resinosa has a similar distribution to N. starkenborghiorum, and the two species are often found in association.[1] Nothofagus forest is generally found above a lower montane belt of oak relatives Castanopsis and Lithocarpus (family Fagaceae). The transition between the fagaceous forests and Nothofagus forests is often abrupt, and less often the forest types intergrade or intersperse. N. starkenborghiorum can form large monotypic stands, including a 60,000 hectare stand on the limestone Nakanai Plateau of New Britain.[3]
On New Guinea Nothofagus forest usually has an understory of smaller trees, shrubs, lianas, and herbaceous plants. On New Britain N. starkenborghiorum stands often have a sparse understory composed mostly of ferns.[3]
Nothofagus forest usually extends up to 3000 meters, where it transitions to upper montane forest typically dominated by conifers.[3] N. starkenborghiorum grows with N. brassii in montane forest around Lake Habbema in the Jayawijaya Range of Western New Guinea from about 2000 to 3000 meters elevation, and in mossy forest from approximately 3,000 to 3,500 meters elevation. It is less common than N. brassii in mossy forest.[4]
