Scrub, tussock-grassland, and herbfield above treeline ecosystem occurs is most extensive about the South Island’s main divide, but significant areas also occur on the North Island’s volcanoes, and along the crests of the Kaimanawa Mountains and Ruahine and Tararua Ranges. 

Large herbs (like mountain flax, Ranunculus, Celmisia and Aciphylla) and low shrubs (e.g., Coprosma, Myrsine, Gaultheria, Dracophyllum, Lepidothamnus and snow tōtara) share dominance with the tussocks, especially in the lower part of the zone.  

Beech tree lines tend to be abrupt, especially in the drier eastern mountains. However, in wetter areas and where the tree line forest is non-beech (mostly mountain tōtara, cedar, southern rātā and kāmahi), the limit of tall trees tends to be lower yet again, and a highly diverse collection of small trees and shrubs forms a diffuse, often impenetrable forest-shrub zone.

The expected natural range* of the scrub, tussock-grassland, and herbfield above treeline ecosystem is 2,257,987 hectares.

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