The ecoregion is part of the Australasian realm, which includes Tasmania and Australia, New Zealand, New Guinea, New Caledonia, and adjacent islands.

[9] This is the simplest rainforest community in Tasmania; it is typically represented by medium to tall forests dominated by Nothofagus cunninghamii and/or Atherosperma moschatum, often together with Leptospermum lanigerum (woolly tea-tree) or Acacia melanoxylon (Australian blackwood).

However, at mid to low elevations, the understorey may contain a few small trees or shrubs such as Olearia argophylla (musktree), Pimelea drupacea (cherry riceflower), Pittosporum bicolor (cheesewood), Aristotelia peduncularis (heart berry) and Coprosma quadrifida.

[12] Histiopteris incisa (bat's wing fern) and Hypolepis rugosula (ruddy ground-fern) occur in disturbed sites such as along roads where there have been breaks in the canopy.

[13] As elevation increases, the height of the forest decreases,[14] Nothofagus cunninghamii becomes multi-stemmed, develops crooked leaning stems and abundant epiphytic bryophytes, and lichens produce a patterned effect on the trunks.

[15] The typical understorey becomes dominated by Tasmannia lanceolata (mountain pepper) and Telopea truncata (Tasmanian waratah), and the ground layer becomes host to Oxalis megellancia and Lagenophora stipitata (blue bottle-daisy).

The pteridophyte diversity decreases and only small species such as Lycopodium fastigiatum (alpine club moss), Hymenophyllum peltatum, Grammitis billardierei (common finger-fern) and Blechnum penna-marina (Antarctic hard-fern) persist.

The canopy is typically dominated by a mixture of 2–5 species, including Nothofagus cunninghamii, Eucryphia lucida, Atherosperma moschatum, Lagarostrobos franklinii, Eucryphia milliganii (dwarf leatherwood), Phyllocladus aspleniifolius (celery-top pine), Athrotaxis selaginoides and, rarely, Nothofagus gunnii (tanglefoot-beech).

[11] The increase in understorey shrub is due to the larger number of gaps in the canopy, and the differing light requirements of competing species.

Understorey may be dominated by either Poa (grasses) or Sphagnum (mosses) or commonly, low shrubs that are less than half the height of the forest.

Ferns are usually poorly developed with larger ground species absent or confined to rocks, Gleichenia alpina is the exception to this observation.

[17] Callidendrous forests require good-quality sites where fertile soils occur over rocks such as basalt, dolerite and the more nutrient-rich granites.

[17][26] In 1982, the United Nations Educational, Scientific and Cultural Organization (UNESCO) designated the northern portion of the ecoregion a World Heritage Site.