Tasmanian temperate rainforests

Callidendrous forest at streams edge at Growling Swallet

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).[10] Typically, these forests are at least 40 m (130 ft) in height. Trees are usually well formed and widely spaced, and the understorey is open and often described as park-like.[3] 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.[11]

Fern diversity is high in many areas, and in these areas, epiphytes often flourish.[11] 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).[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]

New plantlets forming at the end of the fronds of the Mother spleenwort

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.[16]

Callidendrous rainforests occurs in the eastern half of the state and in northwestern and central Tasmania.[17]

Table 1 Lyrebird nature walk, Mt Feild, Tasmania: species composition and structure of a mixed Callidendrous and Thamnic rainforest community; Height ~20 m (66 ft), 90% of ground litter cover, 5% rock and 5% bare ground.

Thamnic rainforests are characterised by well-formed trees of medium height, well below 40 m (130 ft), and a distinct shrub layer. 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 shrub layer is more prominent and has an increased diversity of woody trees. Common species are: Anopterus glandulosus (Tasmanian laurel), Anodopetalum biglandulosum, Acradenia frankliniae (whitey-wood or wirewood), Archeria hirtella, Archeria eriocarpa, Cenarrhenes nitida (native plum), Trochocarpa cunninghamii, Trochocarpa gunnii (sweet-scented trochocarpa), Orites diversifolia (silkwood), Prionotes cerinthoides (climbing heath), Richea pandanifolia (pandani or giant grass tree) and, at high elevations, Richea scoparia (honey richea).[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.[18] Fern diversity decreases, as a result, because of the decrease in light from the understorey.[19] Parablechnum wattsii (hard water fern) is the main ground fern; it prefers damp shaded areas and forms a very dense layer in some areas but can be absent in others.[20] Small epiphytes are widespread, these include Hymenophyllum rarum (a filmy fern) and Grammitis billardierei. Apteropteris applanata can occur in areas containing Athrotaxis. Other larger epiphytes are usually present, but they are rarely prominent.[21] At higher elevations, the general appearance resembles that of a callidenderous rainforest, but the floristic differences remain the same.

Thamnic rainforests occur mostly in western and southwestern Tasmania.[17]

Table 2: The Creepy Crawly Nature Walk, Mt Field, Tasmania: Species composition in Thamnic rainforest community; Height ~35 m (115 ft), 95% of ground leaf cover, scattered rock and bare ground.

Low in stature, broken uneven canopies, height reduced below 20m. Dominance is usually shared between several species: Nothofagus cunninghamii, Nothofagus gunnii, Eucryphia lucida, Atherosperma moschatum, Lagarostrobos franklinii, Eucryphia milliganii, Phyllocladus aspleniifolius, Athrotaxis selaginoides, Diselma archeri, Leptospermum scoparium, Leptospermum glaucescens, Leptospermum nitidum, Leptospermum lanigerum, Acacia mucronata and Melaleuca squarrosa.[5] Atherosperma moschatum is usually represented by small diameter depauperate plants. Understorey is tangled and barely distinguishable from the canopy layer. It can from a continuous layer from the ground to the canopy but some scattered emergents can occur. Species diversity is high for trees and shrubs in this community, but very low for ferns.[5] Anopterus glandulosus, Anodopetalum biglandulosum,[22] Cenarrhenes nitida, Telopea truncata, Agastachys odorata, Comprosma nitida, Archeria eriocarpa, Archeria serpyllifolia, Archeria hirtella, Olearia persoonioides, Trochocarpa cunninghamii, Trochocarpa gunnii, Richea pandanifolia, Richea scoparia, Dracophyllum milliganii and Prionotes cerinthoides are all typical shrubs or small trees that comprise these communities. The ferns are dominated by Parablechnum wattsii but small epiphytes do prevail: Hymenophyllum rarum, Hymenophyllum marginatum, Grammitis billardierei and Apteropteris applanata occurs in communities where Athrotaxis are present.[23] – occur mostly in western and southwestern Tasmania.[17]

Low and dominated by Athrotaxis cupressoides or Athrotaxis selaginoides (less commonly).[24] Open canopy, widely spaced trees allow bright light to penetrate the lower levels of the forest. In some communities, the canopy can be dense and instead resemble a high-elevation callidendrous forest. 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. There is a high diversity of woody species but a low diversity of ferns. Multiple species from nearby treeless vegetation are present, but their classification as rainforest species is yet to be confirmed.[2] Understorey shrubs include: Nothofagus cunninghamii, Nothofagus gunnii, Diselma archeri, Podocarpus lawrencei, Richea pandanifolia, Richea scoparia, Richea sprengelioides, Orites acicularis, Orites revoluta, Microstobos niphophilus, Tasmannia lanceolata, Epacris serpyllifolia and Baeckea gunniana. Ferns are usually poorly developed with larger ground species absent or confined to rocks, Gleichenia alpina is the exception to this observation.[5] Small species such as Hymenophyllum peltatum and Apteropteris applanata can sometimes make an appearance. – occur on the Central Plateau but can extend as small outliners to the mountains further south.[17]