Firewood and birds
Many familiar species of Australian birds, such as parrots, kookaburras, cockatoos, and owls, are dependent on tree hollows for their nests. Some of these birds, such as the superb parrot, swift parrot and the south-eastern race of the red-tailed black cockatoo are listed as nationally vulnerable or endangered. It is likely that cutting hollow trees for firewood has contributed to their threatened status. Other birds, including brown tree creepers, are dependent on dead timber to forage on for food. Some of these species have declined throughout the woodlands of eastern Australia, where firewood harvesting is concentrated, and it is highly likely that firewood harvest has contributed to their decline. However, it is important to note that much of their habitat was first affected by clearing for agriculture. In total 21 species of birds have been listed as being threatened by firewood harvest (Garnett & Crowley 2000) because it causes loss of tree hollows or loss of foraging habitat. All these birds are woodland or mallee species.
Firewood and mammals
Many Australian mammals use hollow dead trees as shelter. These include possums, gliders, phascogales, marsupial mice, and bats. As with birds, the loss of hollow trees, particularly in the woodlands where tree hollows are not being replaced, is causing the ongoing decline of these species.
Firewood and reptiles and amphibians
Like birds and mammals, there are species of reptiles that depend on hollow logs for shelter, or that need dead fallen timber to forage on. The carpet python is a beautiful species of non-poisonous snake that uses hollow logs to shelter, in as does the threatened broad headed snake. The Gehyra gecko forages amongst fallen dead timber for insects. The loss of hollow logs and fallen dead timber would greatly affect these species and reduce their likelihood of survival.
Firewood and invertebrates
We all know termites and borers eat dead wood but there are a host of other invertebrates collectively known as saproxylic invertebrates that are dependent on dead wood for their survival. Saproxylic invertebrates are overwhelmingly harmless species and include such spectacular insects as the stag beetles. One such species is the nationally endangered broad-toothed stag beetle found in south eastern Tasmania. There has been little research in Australia on the importance of dead timber to our invertebrate fauna, but overseas studies strongly suggest that abundant dead wood is very important in maintaining the abundance and diversity of these species (Niemela 1996). Not only are these insects important in themselves but they are food to a wide range of birds, reptiles and mammals.
Firewood and Fungi
Fallen logs assist soil nutrient cycling and enhance soil aeration and structure. Organisms such as fungi recycle nutrients found in dead timber into a form that can be reused by live trees to grow. Deadwood contains a large amount of these mineral nutrients waiting to be released. The removal of dead timber can reduce the productivity of native forests by removing nutrients (Boddy & Watkinson 1995).
Firewood and Plants
Firewood collection has the potential to threaten plants in a number of ways. Rare species may be inadvertently collected as firewood: this may be the case for such rare Tasmanian species as Morrisby's gum Eucalyptus morrisbyi (RFA 1997). Even if only a few individuals of a rare plant are removed it could represent a large proportion of the species' entire population. Microhabitat may be altered unfavourably, particularly for germinating seedlings and understorey plants which only grow under woodland tree species. Facilitation of weed invasion and of disease are also important ways plants can be threatened. This is particularly a concern where the spores of the deadly plant disease-causing fungus, Phytophthora cinnamomi, may be spread on the vehicles and equipment of firewood collectors.
Firewood and the food web
Firewood is just not the home for a large number of creatures great and small, it is also part of the nutrient cycle that maintains the fertility of the soil and the abundance of the species that depend upon it. Wood is the largest part of the biomass of woodlands and forests and thus most of the nutrients, such as nitrogen, phosphorous, and potassium, are locked up in the living tree. When the tree dies these nutrients become available for other plants and for animals that feed on dead wood as well as the next generation of trees. When dead wood is removed these nutrients are removed, leading ultimately to a depleted ecosystem.
Tawny frogmouth (Podargus strigoides)
Photo: Peter Griffieon
Photo: G. B. Baker
Photo: G. B. Baker
Photo: Michael Nelson
Photo: K. Thomas
Photo: M. Fagg
Crimson rosella (Platycercus elegans)
Photo: G. B. Baker