What is a woodland?
The term woodland is generally used in Australia to describe ecosystems which contain widely spaced trees, the crowns of which do not touch (Yates & Hobbs 1997). In temperate Australia, woodlands are mainly dominated by Eucalyptus species. Temperate woodlands occur predominantly in regions with a mean annual rainfall of between 250-800mm, forming a transitional zone between the higher rainfall forested margins of the continent and the shrub and grasslands of the arid interior (Beadle 1981).
Woodland consists of areas with fewer and more scattered trees than forests (<30% foliage cover), with an understorey ranging from low trees and shrubs to grasses.
Many woodlands have eucalypts or wattle as the dominant trees, but mulga and paperbark woodlands are also common. The understorey can include cypress pine, wattles, grass trees, Banksia, saltbush, spinifex, tussock and other grasses.
Open woodlands have very few scattered trees, often making the groundcover the most obvious feature of the landscape. Some woodlands are the result of the thinning or clearing of forests to promote grass growth for grazing.
Animals which live in woodland include the numbat, northern hairy-nosed wombat, collared delma, long-legged worm skink, golden-shouldered parrot, superb parrot, Gouldian finch, malleefowl, mahogany glider, numbat, and northern bettong.
Some common woodland tree species in south-eastern Australia are yellow box Eucalyptus melliodora, white box Eucalyptus albens, red box Eucalyptus polyanthemos, and red ironbark Eucalyptus sideroxylon. Associations of these trees are often referred to as the box-ironbark woodlands.
Approximately 85% of box-ironbark woodlands have been cleared since European settlement (Traill 1993). As these trees are preferred firewood species, it was estimated that 33% of Australia's annual firewood supply was removed from the remaining stands each year (Mussared 1992).
Where do woodlands occur?
Prior to European settlement, box-ironbark woodlands covered large areas of temperate southern Australia. In the south-east of the continent they formed a continuous vegetation community on the inland side of the Great Dividing Range occurring from southern Queensland to the lower south-east of south Australia with a narrow strip running north and south of Adelaide (Moore 1970). Woodlands are often accompanied by patches of grasslands, dry sclerophyll forests, heathlands and mallee (Yates & Hobbs 1997).
Unmanaged firewood collection threatens woodlands ecology
Woodlands are an ecosystem under threat from a variety of processes. These include clearing and fragmentation, insect outbreaks, diseases, and grazing. Probably the greatest threat to the long-term survival of woodlands is the failure of woodland trees to regenerate. This is usually due to intensive grazing killing off any seedlings that do appear. By and large firewood harvest will not affect recruitment of new woodland trees. However, the removal of old/dead trees for firewood and the destruction of seedlings by grazing combine to reduce the long term sustainability of woodland ecosystems.
There is a link between collection of wood from roadsides and remnant bush, and the declining numbers of birds and animals in our temperate woodlands. It is not often appreciated that old standing trees and dead wood on the ground provide an important source of food and habitat for many species of birds and mammals. The removal of these trees and logs is mistakenly seen as just 'cleaning up the forest' when they are in fact a critical part of the ecosystem.
Many thousands of people collect dead and fallen trees for their firewood without realising that they could be removing the habitat of native species. Both standing and dead fallen timber from forests, reserves, private property and even roadsides provides important habitat for the regent honeyeater, squirrel glider, the red-tailed black cockatoo, swift and superb parrots and a range of ground dwelling mammal, reptile and invertebrate species. Fallen timber also assists with soil retention by intercepting and slowing water flow and assisting the accumulation of leaf litter.
The following woodland communities are currently listed as Endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999:
- Cumberland Plain Woodlands
- White Box - Yellow Box - Blakely's Red Gum Grassy Woodland and drerived native grassland
- Buloke Woodlands of the Riverina and Murray-Darling Depression Bioregions
- Corymbia calophylla - Kingia australis woodlands on heavy soils of the Swan Coastal Plain
- Corymbia calophylla - Xanthorrhoea preissii woodlands and shrublands of the Swan Coastal Plain
- Shrublands and Woodlands of the eastern Swan Coastal Plain
- Shrublands and Woodlands on Muchea Limestone of the Swan Coastal Plain
- Shrublands and Woodlands on Perth to Gingin ironstone (Perth to Gingin ironstone association) of the Swan Coastal Plain
A number of other woodland communities are listed as threatened under various state and territory threatened species legislation.
Read more about: Threatened ecological communities
Photo: D. Greig
Photo: P. Ormay
Photo: C. MacDonald
Photo: G. B. Baker
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