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Objective

Recommendation

Key issues

What has been achieved 1998-2003

Tasmania Together

Related Issue Reports

Objective

To avoid any further expansion of rural tree decline.

Recommendation

It is recommended that:

• further reduction in vegetation cover is avoided in areas susceptible to tree decline, as this will exacerbate ecological stress on remaining forest or woodland remnants;
   
• best practice in the management of revegetation programs is followed (see 'key issues');
   
• the extent of tree decline is routinely monitored as part of the proposed program of vegetation change detection and monitoring; and
   
• management practices for addressing rural tree decline proposed in the Cooperative Research Centre for Sustainable Production Forestry report are implemented, including reduced nutrient input through careful fertiliser placement (Close & Davidson 2001).
   

Key issues

Tree decline is defined as the premature death of forest and woodland trees. In Tasmania, tree decline particularly affects eucalypts on the drier areas of agricultural land. There appears to be no single cause of tree decline. The information provided in this report summarises only one part of the tree-decline problem. A more complete assessment would also consider the present state of knowledge of other forms of tree decline that might be attributed to factors such as pests and diseases. Forestry Tasmania and State Government agencies are involved in assessing and managing a range of tree-decline and forest management issues across Tasmania.

Many stresses have caused the slow attrition of eucalypts from the dry rural landscapes over the last few decades. Information on the rural tree decline issue is available in the Rural Tree Decline Issue Report. Some of the key points from the Issue Report include the following.

• Tree decline is the most extensive form of land degradation in Tasmania, estimated to be affecting 42% (861,000 ha) of private land. It is prevalent throughout the low rainfall districts (below 900 mm per year), with the worst areas being in the Midlands and the upper Derwent Valley.
   
• Tree decline mostly affects white gum, but black peppermint, black gum, swamp peppermint, mountain gum, silver peppermint, cabbage gum, blue gum, candlebark, and white-top stringybark are also affected (Neyland 1996).
   
• While there is new recognition of the importance of moisture stress in rural tree decline, many other factors are also implicated: frost, vegetation clearance, browsing animals (e.g. possums), soil compaction, insect attack, soil-borne diseases, reduced soil fungi (e.g. ectomycorrhizal fungi), loss of understorey, lack of seedling regeneration, old age (i.e. mature trees dying and no young trees establishing underneath) and agricultural practices such as grazing, clearing, tilling and the addition of fertilisers.
   
• The record of success in revegetation in the dry rural areas has been very low.
   
• As tree decline advances there is a concern, due to associated land degradation, that it may threaten sustainable agriculture and lead to a reduction in the profitability in agricultural production. Tree decline, and the resultant land degradation, is also impacting on biodiversity values, due to habitat loss. It is also adding to the continuing reduction in the overall quality of the State's landscape.
   

Best Practice in Revegetation

Best practice in revegetation programs, as outlined in the recommendation, would include the following.

• Provided that there are no biological diversity consequences, revegetation projects should target high moisture areas where seedlings are most likely to survive.
   
• More effort is spent protecting treated/revegetated areas for the first few years after planting.
   
• Agencies responsible for funding revegetation should ensure that the cost of intensive ongoing management (weed control, insect control, browsing protection) is built into the revegetation program.
   
• The importance of fencing around revegetated and remnant areas is recognised to allow better control of stock movement.
   
• The control of animal numbers (possums primarily, but also rabbits, hares, deer, goats and wallabies) is undertaken to provide for the successful establishment of trees, whether through natural regeneration from existing trees, planting or direct sowing.
   

What has been achieved 1998-2003

There have been a number of initiatives intended to arrest the problem of rural tree decline in Tasmania. The following are a few of these responses.

• Recognition of the problems caused by dieback has led to a significant amount of work being done by landowners and managers to re-establish trees in affected areas. National programs such as Landcare and One Billion Trees have supported this by providing resources for planting trees, and fencing to prevent grazing pressure on seedlings. However, there are many areas in the State that still require work, and others which may be affected by dieback in the future if pressures such as grazing remain too intense.
   
• University research examined the factors implicated in tree decline in the Midlands (Rees 2000).
   
• The factors implicated in tree decline in Tasmania have been identified in research by Neyland (1996), and Close and Davidson (2001), both of which also include recommendations for its control.
   
• The Southern Midlands Council has developed a Bushcare management strategy and weed management strategy for its entire municipality, where work is complementary with adjoining regions such as the Northern Midlands and Brighton councils.
   
• Many other initiatives that have the aim of protecting land cover also assist in responding to the problem of rural tree decline even though this may not be their primary management objective. These responses are discussed widely across the report and include the Private Forests Reserve Program in DPIWE.
   
• Another initiative is the Natural Heritage Trust funded 'north facing slopes project'. Over 80 farmers in the low rainfall agricultural areas of Tasmania: the Midlands, Fingal and Derwent valleys, have protected their north facing slopes from erosion through this project since it began in November 1999. The North Facing Slopes project has provided over 100 km of fencing materials to fence off 1,890 ha, at a cost of up to $1,500 per km. The project aims to encourage improved grazing management of sheep on highly erodible north facing slopes.
   
• A Natural Heritage Trust project, 'Revegetation to combat tree decline' managed by the Cooperative Research Centre for Sustainable Production Forestry, was completed. The brief included addressing the underlying causes of rural tree decline and identifying recommendations for a better approach to revegetation programs (Close & Davidson 2001).
   

Tasmania Together

Relevant Tasmania Together goals and standards for 'Land' are listed in the linked file. The Tasmania Together Progress Board reported on progress toward targets for benchmarks set (Tasmania Together Progress Board 2003). Indicators, targets and baseline data are available in the latest Progress Report June 2003. Further information, including progress report updates, is available from Tasmania Together.

Related Issue Reports