This ecosystem is found in the lowland forests of wet, cool climates from the Grey Valley north to the Tararua and Aorangi Ranges. It can also be found sporadically in north Taranaki and in Tairāwhiti hill country.

Scattered rimu, miro and Hall’s tōtara poke through the canopy. The bush is dominated by kāmahi, red beech, hard beech and/or silver beech. Silver beech is mostly found at higher elevation and is rare in north Taranaki. Tāwheowheo and southern rata are found alongside the beeches. Where the soil is skeletal, infertile, or poorly drained you may also see mountain beech.

The expected natural range* of rimu-miro/kāmahi-red beech-hard beech forest is 1,485,805 hectares.

*area this ecosystem could occupy without the presence of people.