What is the Box-Ironbark Ecological Management Strategy?

The Box-Ironbark Ecological Management Strategy (EMS) is being developed as best-practice management to support a sustainable network of Box-Ironbark forests and woodlands with an objective to more closely resemble pre-European forests.

Results from research, which includes trialling of ecological thinning methods and supported by contemporary monitoring techniques, will provide a scientific basis for the development of the EMS. Research is designed to support a realistic vision of healthy Box-Ironbark forest/woodland ecosystems and how they could be managed. This approach may in future be applied to, state parks, regional parks, conservation reserves and national parks.

For state forests a silvicultural thinning program (see below) will be implemented in Box-Ironbark forests and woodlands by the Department of Sustainability & Environment.

Why is an EMS needed?

At the time of European settlement, the Box-Ironbark forests and woodlands of Northern Victoria covered some 3 million hectares or about 13 per cent of the area of the State. Since then approximately 83 per cent of this original cover has been cleared for agriculture, urban development and mining. As a consequence of extensive broad scale clearing of forest cover, remnant vegetation is fragmented and highly modified leading to a continuing decline in biodiversity and ecological integrity. More specifically there has been widespread loss of habitat for many plants and animals, including large hollow-bearing eucalypt trees.

Traditional forest management systems used to provide wood products and other extractive forest produce has significantly altered forest structure. Today's Box-Ironbark forests consist principally of relatively young, evenly-spaced smaller trees, with very limited populations of old, scattered large habitat trees. Other important habitat such as fallen logs and understorey vegetation is also different to pre-settlement times, reducing the availability of other important habitat types.

An EMS is required to reverse this decline in the ecological health of the Box Ironbark forests and woodlands in the Box-Ironbark Parks and Reserves System which was established in 2002.

How do we know what constitutes a ‘healthy state' for the Box-Ironbark forests and woodlands?

Pre- European forests of Northern Victoria would have consisted primarily of dominant, widely-spaced, large old trees, with pockets of younger trees competing for the space left through the death of a large tree, a diverse understorey, and a forest floor of fallen branches and logs. These forests were home to a wide range of species, including hollow-dwelling birds and mammals, many of which are now threatened.

A few Box-Ironbark forest remnants throughout the region, including some less-degraded roadside reserves and a limited number of ‘old-growth' forest blocks give us an insight into how these forests and woodlands might look if left to the forces of nature. Insight gained from studying these Box-Ironbark forest examples is supported by university research investigating habitat requirements of many faunal groups at different ecological scales.

What is ‘ecological thinning'?

Thinning is the process of removing some smaller trees and allowing remaining dominant trees to grow faster and ultimately larger. Older, larger trees have hollows and features which provide crucial habitat for many birds and mammals. In Box-Ironbark forests there are vast areas where tree density is very high, sometimes 1500 trees per hectare, and the trees are very small in diameter (less than 10cm) due to past disturbance.

Ecological thinning is the first method to be used in the development of the EMS. Its aim is to improve the ecological integrity of the forests and woodlands and their flora and fauna species rather than just maintaining the status quo. Other forest management tools may be incorporated at a later date.

As part of the development of the EMS, Parks Victoria is undertaking a Box-Ironbark Ecological Thinning Trial to investigate potential thinning techniques. The trail will assess whether ecological thinning can be used to accelerate the development of old-growth habitat characteristics in the eucalypts that form the structure of the Box-Ironbark forests and woodlands and whether other ecological values are enhanced.

Ecological thinning techniques have been designed to maximise desirable habitat and biodiversity values and provide a rigorous scientific basis for the EMS. Three thinning treatments are being examined; one of even tree spacings and two of different levels of patchiness, and each with varying reductions in stem density. The selection of relatively large trees with desirable habitat characteristics (to be retained) is the common basis for the thinning treatments.

A secondary treatment is the removal of fallen timber from the forest floor following thinning operations. This is likely to be an important consideration in developing methodologies for the EMS because of the high tree densities found in remnant Box-Ironbark forests.

What does ecological thinning achieve?

Thinning of the Box-Ironbark forests will reduce competition and stimulate growth of the retained trees. These trees then have an opportunity to develop into ‘habitat trees' faster than they otherwise would have.

The overall aim is the restoration of a diverse landscape with more open forests; this includes larger trees with habitat features such as hollows and cavities. The landscape would also include improved ground level habitat by retention of felled tree stems and branches. Reduced tree competition and open canopy may also increase flora diversity in the forest understorey. It is anticipated that thinned forests will ultimately provide better habitat for populations of fauna, including several threatened species of birds and mammals.

Who will conduct the ecological thinning operations in the Box-Ironbark regional parks, state parks, national parks and other reserves?

Parks Victoria is managing the trial as part of developing the EMS so as to test potential management techniques within a scientific framework.

Two thinning crews have been employed by Parks Victoria to implement treatments for the trial. Workers on these crews have all been employed from regional communities in Northern Victoria. Crews include some former timber workers from the Box-Ironbark area who lost work with the creation of the new park system.

Will ecological thinning operations provide firewood?

None of the timber resultant from thinning work at trial sites will be commercialised as firewood (see State Firewood Strategy). Most of the felled wood in the thinning treatment blocks is left on the ground to break down. Normal forest ecosystem processes result in increased soil nutrients and improved forest habitat for insects, small birds and mammals.

As part of the ecological thinning experiment, woody debris is being removed in different densities from a range of plots to test the response of flora and fauna to this manipulation. As a result of this work a large amount of timber is taken off-site by volunteers who belong to local community groups (see below). Some firewood has been distributed to disadvantaged community members in towns near the Trial sites by these organisations.

What other methods will be used as part of the EMS?

Ecological thinning combined with woody debris removal are the only methods being used to support the EMS at this stage. Other techniques such as ringbarking, chemical injection and prescribed burning were considered problematic when the trial was designed. In the future other techniques such as the use of fire may be introduced.

What is ‘silvicultural thinning'?

Silvicultural thinning is used in state forest to reduce tree competition and foster development of high quality trees for sustainable production of sawlogs, posts and other products including firewood. Timber production is a primary goal of forest management with the health of the forest of utmost importance in terms of promoting faster growth of larger trees.

What does silvicultural thinning achieve?

Silvicultural thinning is traditionally used to promote rejuvenation of the forest and provide long-term support to the timber industry. This technique was once widely used in the management of Box Ironbark forests, primarily to produce firewood but additionally post and pole products, but has been less so in recent times. It is intended to be developed again as part of the EMS for management of Box-Ironbark forests. Techniques used are based on existing practices for mixed-eucalypt lowland forests in Victoria .

Who will conduct the thinning in Box-Ironbark state forests?

The silvicultural thinning operations will be supervised by the DSE using current guidelines for departmental and contract work crews.

What is being done to ensure fire protection in the new Box-Ironbark parks and reserves?

Fire protection and suppression works in the new Box-Ironbark parks and reserves will continue to be managed according to the current high standards for fire management on public land in Victoria . Thinning operations will be integrated with the Regional Fire Protection Strategy.

Will thinning provide firewood?

Silvicultural thinning has been an accepted management technique in Box-Ironbark forests. Commercial firewood production has been supported by thinning to meet public demand. Current resourcing for commercial firewood is outlined in the State Firewood Strategy.

Where will the ecological thinning trial sites be located?

Trial sites are located in the Castlemaine Diggings National Heritage Park south of Castlemaine, Pilchers Bridge Nature Conservation Reserve south of Bendigo, Spring Plains Nature Conservation Reserve south of Heathcote and Paddys Ranges State Park southwest of Maryborough.

Are there any external partnerships or community participation projects that are part of the Ecological Thinning Trial

The Box-Ironbark Ecological Thinning Trial is supported by a number of important partnerships with community and government organisations.

More than 15 different community groups are involved in timber removal and firewood distribution at Maryborough, Castlemaine, Harcourt and Heathcote. This includes service clubs such as the Country Fire Authority, Lions Clubs, Asteria and the St Vincent De Paul Society. The Mt Alexander Shire Council Bendigo Corrections and the University of Melbourne (Creswick) are also important partners.

Timber collections by some of these groups are being used for fundraising that contribute directly to community service projects.

Another important set of partnerships also support the Trial. Scientists from the Dept. of Sustainability & Environment (Arthur Rylah Institute for Environmental Research ), University of Ballarat (Centre for Environmental Management) and University of Melbourne (Dept. of Botany) and are working with Parks Victoria to undertake research and monitoring projects.