At a glance
One of the most significant threats to natural diversity in Tasmania is the clearing of native vegetation and its replacement with that of a different land use activity (e.g. tree farms, agriculture, dams etc). The total extent of native vegetation cleared since European settlement has been calculated to be around 23%, or 1.560 million hectares (CARSAG APU data 2002). Between 1972-1999, over a quarter of a million hectares of native vegetation were cleared in Tasmania (Kirkpatrick 1991 and Kirkpatrick et al 1982, 1995 and 1999). The amount of native vegetation approved for conversion to plantation or non-forest use was 15,820 ha in 1999-2000, 13,450 ha in 2000-2001, and 9,280 ha in 2001-2002 (Forest Practices Board 2000, 2001, and 2002).
The key drivers of land clearance in Tasmania have changed over time. The grassy woodlands of the State are ideal for producing fine wool. In the late 1960s to early 1970s, a rise in commodity prices for fine wool became a driver for clearing to expand pasture, and for the use of woodlands and dry forest areas for grazing. In the 1970s and 1980s, significant clearance of native vegetation occurred for agricultural purposes. Clearing was undertaken largely in dry eucalypt forests in the east and north east of the State. There was also some clearing for hydroelectric impoundments. In the mid 1970s to late 1980s conversion from broadscale sheep and beef enterprises to more intensive dairy farming took place, involving some further clearing to expand existing pasture, particularly in the north-west of the State (AGO 2000). In more recent years (particularly in the period since the last SoE Report), conversion to plantation has become a more significant driver of land clearance in Tasmania.
There are a number of sections in this SoE Report that relate to land clearance. Clearance of native vegetation for urban growth is reviewed in the Urban Growth Issue Report, while the Water Quantity and Water Use Issue Report provides information on dam development. Firewood Collection and Usage is reviewed separately.
Land clearance also has a variety of consequences, sometimes unanticipated. Environmental consequences of land clearance are reviewed in other parts of this SoE Report. In the Biodiversity Chapter, the extent of remaining native vegetation cover is a key determinant of biodiversity health (see Biodiversity Health Issue Report). Native vegetation clearance is a major cause of species and ecological communities being threatened (see Threatened Species and Ecological Communities Issue Report). The Health and Extent of Native Riparian Vegetation is reviewed in the Inland Waters and Wetlands Chapter (see Health and Extent of Native Riparian Vegetation). In other report chapters, the Disturbance of Acid Sulphate Soils Issue Report, for example, describes the impact of disturbance of land cover in areas which host acid sulphate soils.
Further information on the history of land clearing in Tasmania and Australia in general is available in the Australian Greenhouse Office Report entitled Land Clearing: A Social History. An Australia-wide assessment of vegetation clearance is also available through the Australian Natural Resources Atlas.
The nature conservation impact of land clearance depends on scale and context. Relatively small losses in vegetation communities, which are already significantly depleted, are of immediate concern. In contrast, nature conservation impact is lessened where clearance occurs in vegetation types that are well-reserved and relatively little depleted.
The process of land clearing can also occur over a period of time. The replacement of grassy woodlands with treeless pasture, for example, is often a slow process involving tree decline over many decades and repeated small-scale management decisions on the use of fertiliser and sowing of introduced pasture grasses. Incremental processes, which can lead to land being effectively cleared, can also include inappropriate fire regimes, urban development and firewood collection.
This 'At a glance' section provides an overview of the land clearance issue. More detailed information is available in the Land Clearance Issue Report. Indicators presented in the main report include native vegetation clearing and land cover (see indicators).
Recommendations presented in this SoE Report that are relevant to the issue of land clearance include:
- The State is committed to the National Framework for the Management of Native Vegetation (2001), the National Action Plan for Salinity, and the Water Quality Bilateral Agreement (2002). These commit the State to striving for an outcome of no further clearing of endangered and vulnerable plant communities.
- The Regional Forest Agreement (Government of Tasmania and Commonwealth Government 1997) adopted a Permanent Forest Estate Policy. The policy sets out a system of minimum threshold percentage that must be retained and below which forest vegetation cannot be cleared. The policy is designed to establish a relationship between areas in reserves and areas in various forms of production forest to help achieve conservation objectives across the landscape. Current thresholds in the policy are to retain 80% of the total forest area that existed in 1996, with 50% of each forest community to be retained in each bioregion.
- The Permanent Forest Estate Policy is under review. The review is addressing the current vegetation retention thresholds, both the total threshold and the individual thresholds for different forest communities.
- A consultation program is underway with the key stakeholders to develop mechanisms for managing native non-forest vegetation on private land. It is expected that the mechanisms will focus on a key role for local government planning schemes, the preparation and accreditation of property-based plans, and the reservation of some areas under voluntary conservation programs.
- In April 2001, land clearance was listed as a threatening process under the Environment Protection and Biodiversity Conservation Act 1999. Legislative recognition is an important part of a national response.
- The Vegetation Management Framework was announced by the State Government in July 2001. Under the framework the Forest Practices Act 1985 was amended to require permits for the clearance of forest, irrespective of the purpose of clearance. These provisions apply where the area to be cleared is more than 1 ha per year or greater than 100 tonnes per year, or where the land involved is vulnerable land under the Act. The Vegetation Management Policy emphasises cooperative approaches with landholders.
- The Forest Practices Board introduced a moratorium on the clearing of rare and endangered forest communities in 2002. The State Government announced in May 2003 that all rare, endangered and vulnerable forest communities would now be protected using the Forest Practices System. The new measures will prevent the clearing of 107,000 hectares of threatened forest communities in Tasmania.
- The State Government also announced in May 2003 that the clearing of endangered, rare and vulnerable non-forest communities would be stopped. This includes grasslands, heath and scrub. Councils would play an important role through their planning schemes by taking account of at-risk non-forest vegetation communities when considering developments.
- The DPIWE established a Private Forest Reserves Program in July 1998 to extend the system of comprehensive, adequate and representative forest reserves on private land in Tasmania. It is responding to the need to protect the many species and communities that do not predominantly occur on public reserved land. Conservation initiatives on private land are especially important in the eastern, central and northern parts of the State where land clearing, in particular, has been greatest. About 30,000ha of forested land has been protected under the Program.
- Tasmania has, with Natural Heritage Trust assistance, developed a Protected Areas on Private Land Program. With landholder approval, areas of non-forest conservation significance, as well as forested areas that do not meet the priorities of the Private Forest Reserve Program, are covenanted. Land Tax relief and rate rebates are available in some municipalities as incentives.
- A program to increase levels of reservation for freshwater ecosystems has also been established. The program aims to bring reservation of these neglected ecosystems more in line with the requirements of a comprehensive, adequate and representative reserve system.
- Incentive programs funded by the Natural Heritage Trust to fence off and manage riparian areas (see Health and Extent of Native Riparian Vegetation Issue Report) have been introduced. Funds for riparian vegetation management are available under Rivercare, Bushcare and Regional Natural Resource Management strategies, primarily through devolved grant schemes.
- A study was completed on Landscape Change in the Meander Valley: A Case Study for Monitoring and Reporting of Land Use Modification, Vegetation Condition and Biodiversity Loss (Cadman 2003). A summary of the principal findings is provided in the case study on Landscape Change in the Meander Valley.
- Forest Practices Board data indicate that the highest rates of forest clearance on public and private land occurred on the Woolnorth (north-west) and Ben Lomond (north-east) Bioregions (Interim Bioregionalisation of Australia 4.0). In the period 1997-01, 19,782 ha and 18,992 ha were approved for clearance, respectively.
- Five of the nine bioregions (Interim Bioregionalisation of Australia 5.0, see map) in Tasmania had greater than 30% of their areas cleared based on 1999 Land Clearance Boundary Data (Kirkpatrick and Mendel 1999). Of these, the Northern Midlands Bioregion had the greatest area cleared-71.6%. The remaining four of the nine bioregions included: Ben Lomond, with 18.3% area cleared, and the West, Central Highlands and Southern Ranges bioregions, which had less than 10% area cleared.
- In the period between 1994-01, the Northern Slopes Bioregion had the greatest percentage of its area subject to forest harvesting as indicated by woody vegetation change from Landsat data (34,214 ha or 5.5 % of the 623,104 ha bioregion area experienced woody vegetation decrease).
- Between 1996-2001, an expansion occurred in eucalypt plantation establishment with an increase in area by 60% or 44,000 ha, and an increase in the area of softwood plantation of 11,900 ha (Forest Practices Board 2002). The largest percentage area of plantation development occurred in the Ben Lomond and Northern Slopes Bioregions, which contain 57,913 ha of softwood and hardwood plantations (8.8% of the area of the bioregion) and 69,706 ha (11.2% of the area of the bioregion), respectively. A proportion of the plantation development occurred through clearance of native forest.
- On a Statewide basis, forest community types (1996 mapped types) with the greatest amount of clearing since 1997-not including clearfelled native forest areas regenerated from native seed-include: swamp gum (E. regnans) forest-almost 12% (9,040 ha); wet white gum (E. viminalis) forest on basalt-7.4% (308 ha); white gum (E. viminalis)/black gum (E. ovata)/black peppermint (E.amygdalina)/brown-top stringybark (E. obliqua) damp sclerophyll forest community-7.2% (2,916 ha); and tall brown-top stringybark (Eucalyptus obliqua) forest-5% (20,109 ha).
- Seven forest communities have less than 15% of their current extent in reserves: six are dry eucalypt communities and one a wet eucalypt community. Ten communities, mainly from the dry eucalypt group, have less than 7.5% of their estimated pre-1750 extent protected in reserves. For most of these communities, the remaining extent is chiefly on private land.
- While the State has about 40% of its land area in reserves, the distribution is concentrated in a few bioregions: the West and Central Highlands have 83% and 56% respectively within formal reserves. The Southern Ranges also has high levels of formal reservation with 44% of its area reserved. However, six of the nine terrestrial bioregions in Tasmania have more than 80% of their area outside any type of reserve. The situation is particularly critical in the Northern Midlands where 97.4% of the bioregion is outside any type of public or private reserve.
- The current threshold of maintaining 80% of the 1996 area of forest for the Permanent Forest Estate is unlikely to be exceeded through clearing for plantations and other purposes. However, a number of threatened ecological communities are approaching the 50% threshold for maintenance of bioregional extent.
- There is no single data source to report on land clearance and vegetation change in a systematic and consistent way for different land uses, vegetation types and tenures. Forest Practices Board data is used to provide a guide to forestry related clearance. However, this data is not mapped, does not include clearing occurring below thresholds of the Forest Practices System, and is not capable of monitoring illegal or incremental clearing. Clearance of vegetation communities for other uses such as housing is also not measured or reported. Measures of vegetation change for non-forest vegetation communities are comparatively less studied or reported. Various limitations were apparent in the data that were available to report on land clearance and vegetation change.
- The Resource Planning and Development Commission's recent review of the Regional Forest Agreement reported figures for clearing in the period since 1996 to be in the range of 38,000ha - 63,000ha (RPDC 2002). The upper figure is based on Forest Practices Board data on areas approved for conversion, while the lower figure reflects areas known to be converted. The actual amount of land clearance within this range is unknown.
- The Forest Practices Amendment Act 2001 was introduced to control clearance of forest communities irrespective of the purpose of clearance. At this stage, there is limited information to indicate the effectiveness of the legislative changes. There are currently no assessment methods to manage the clearance of non-forest vegetation communities of conservation significance.