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Forestry Facts: An Overview Statistics Old Growth Forests Biodiversity Bushfires Australia's changing forests Native forests Forests and the Economy Eucalypt (Hardwood) Plantations Pine (Softwood) Plantations Multiple use forests Woodchips Pulp and Paper Regrowth forests The World's Rainforests The Greenhouse Effect Glossary of Terms Timber construction in bushfire areas |
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Old Growth ForestsThe National Forest Policy Statement (Commonwealth of Australia 1992), which was jointly developed and signed by the Commonwealth government and the state and territory governments, sets out an agreed strategy to manage areas of old growth forest as part of a comprehensive, adequate and representative system of forest reserves. Forest that is ecologically mature and has been subject to negligible unnatural disturbance such as logging, roading and clearing. The definition focuses on forests in which the upper stratum or overstorey is in the late mature to overmature growth phases. (Commonwealth of Australia 1992, p. 69) This definition was amended to provide the following working definition for the preparation of a Regional Forest Agreement for East Gippsland: Forest which contains significant amounts of its oldest growth stage in the upper stratum, usually senescing trees, and has been subject to any disturbance, the effect of which is now negligible. (East Gippsland Comprehensive Regional Assessment 1996, p.161) The definitions provide an arbitrary basis for classifying forests based on age and extent of disturbance. The special attention given to identifying and reserving old growth forests appears to be largely based on an assumption that old growth forests are self-perpetuating. In some forests this may be the case. But Australian eucalypt forests are not self-perpetuating. In the absence of massive disturbance, usually by fire, the older trees in eucalypt forests will die and the area of eucalypt forest will decline. Forests are complex and dynamic ecosystems. Australian eucalypt forests have evolved in response to increasing aridity and regular disturbance by fire and have replaced rainforest or other fire sensitive tree communities. In many instances a prolonged lack of fire will lead to the replacement of eucalypt forests with other ecosystems. This is most evident in Tasmania and Victoria where the prolonged absence of fire in wet sclerophyll forests has led to their replacement with rainforest. By definition old growth eucalypt forests are either in or approaching senescence and will die. Their replacement requires regrowth. Consequently today's old growth will become tomorrow's regrowth if the ecosystem is to be conserved. The long life cycle of forests and the natural beauty of old forests encourage a view that old growth forests can be preserved. Such a view reflects misconceptions about Australia's ecology and evolutionary past. While the criteria adopted for the proposed establishment of a comprehensive, adequate and representative reserve system for forests in Australia seek to reserve a minimum of 60 per cent of existing old growth forest in Australia they ignore the importance of including targets for forest of other growth stages. The area of eucalypt old growth forest is dynamic. New areas of old growth forest are recruited as trees reach older growth stages or as the effects of past disturbance diminish. Other areas cease to be old growth as the old trees become senescent and die. These areas will regenerate to eucalypt regrowth through disturbance or may progress to rainforest or other ecosystems. Because of the dynamics of the forest ecosystem and the need to protect biodiversity, greater attention should be given to conserving a range of successional growth stages. To date limited attention has been given to the desirability of maintaining such a range in the current reserve system and how this range can be achieved without disturbance by timber harvesting or periodic wildfires. Ultimately managers of old growth forests in conservation reserves will need to develop an in-depth understanding of old growth forest dynamics, determine clear ecological objectives for managing old growth forests and develop techniques to conserve the full range of biodiversity. References Commonwealth of Australia 1992, National Forest Policy Statement, AGPS, Canberra. East Gippsland Comprehensive Regional Assessment 1996, Comprehensive Regional Assessment East Gippsland Environment and Heritage Report, Commonwealth and Victorian Regional Forest Agreement Steering Committee, Canberra. |
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