The Tasmanian temperate rain forests are a temperate broadleaf and mixed forests ecoregion in western Tasmania. The ecoregion is part of the Australasian realm, which includes Tasmania and Australia, New Zealand, New Guinea, New Caledonia, and adjacent islands.
Rainforest communities in Australia are classified as closed forests in which the canopy comprises 70–100% cover. It can be divided into tropical, subtropical, monsoon and temperate rainforest. Tasmanian rainforest is classified and as cool temperate rainforest, and represents the most floristically complex and best developed form of this forest type in Australia. In Tasmania, they can be found in the West, Savage River National Park, South West, North East and in patches on the East Coast. On the mainland of Australia, cool temperate rainforest have a wide variety of woodland trees, but Tasmania only has a limited number of woodland and vascular plants such as mosses, liverworts, lichen and fungi. Because of this, the definition of Tasmanian cool temperate rainforest was redefined in the 1980s to allow for communities that did not meet the canopy requirements and clearly separate cool temperate rainforest from mixed forest; The current definition states that cool temperate rainforests are those with trees usually greater than in height and capable of regenerating in the absence of large scale catastrophic events, such as fire. These forests are climax vegetation and are dominated by angiosperms such as Nothofagus cunninghamii (myrtle beech), Atherosperma moschatum (sassafras), and Eucryphia lucida (leatherwood) as well as gymnosperms such as Athrotaxis selaginoides (King Billy Pine), Lagarostrobos franklinii (huon or macquarie pine) and Phyllocladus aspleniifolius (celery-top pine). The limited number of woody species is thought to be due to repeated glaciation.
Tasmanian cool temperate rainforest can be divided into four types: Callidendrous rainforest, Thamnic rainforest, Implicate rainforest and Open Montane. These four major types differ in many of their characteristics such as structure, floristics, distribution, level of endemism and ecology.
Community composition and descriptions
The Tasmanian cool temperate rainforest is composed of two alliances, the myrtle-beech (Nothofagus cunninghamii) alliance and the pencil pine (Athrotaxis cupressoides) alliance. The former is made up of callidendrous, thamnic and implicate, whilst the latter is all open montane.
Callidendrous rainforest
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). Typically, these forests are at least in height. Trees are usually well formed and widely spaced, and the understorey is open and often described as park-like. The diversity of woody species is low, and they are usually sparse and inconspicuous throughout the understorey. 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.
Fern diversity is high in many areas, and in these areas, epiphytes often flourish. The dominant tree ferns are commonly Dicksonia antarctica (soft tree fern) and/or Polystichum poliferum (mother shield fern). Common epiphyte species include Rumohra adiantiformis (leathery shieldfern or iron fern), Asplenium gracillimum (mother spleenwort), Asplenium terrestre, Microsorum diversifolium (kangaroo fern)," Hymenophyllum flabellatum (shiny filmy-fern), Hymenophyllum australe (austral filmy-fern), Hymenophyllum cupressiforme, and Polyphlebium venosum (veined bristle-fern). 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.