BUILDING MATERIAL AND FIBRE

Broombush

The cutting of broombush, for roofing and other domestic uses, has occurred at least since the first Europeans settled in the Mallee. Commercial-scale harvesting to create fencing material commenced in South Australia in the late 1930s, with brush harvesting for fencing introduced into other parts of Australia more recently, including Victoria in the mid 1970s.²¹⁹

Brush fences are very price competitive with other fencing materials and are often sought after for situations where a noise baffle is required or an aesthetic landscaping feature desired. Brush is also used to create shade houses, hanging baskets and other products. ²²⁰

The brush is produced from the native broombush or broom honey-myrtle (Melaleuca uncinata). Broombush occurs through out Australia in a variety of climates on a variety of soils. Within Victoria it is found in the Mallee on sands and sandy loams, often in dense stands. Younger plants often have multiple stems, with older plants tending to have fewer stems. They may reach up to 5 metres in height.

Harvesting involves cutting the stems of the plant near its base. The stems are then placed in bundles and sold to processors who manufacture fencing panels for resale or, more commonly, direct to fencing contractors. Victorian cutters target plants of age 15 to 30 years; the plants regrow after harvesting.²²¹ About two to three bundles (each weighing 23 kilograms) are required to build one metre of fence. Currently around 100,000 bundles of brush are cut each year and sold for brush fencing in Adelaide.²²²

Victorian Industry

Public land in the Big and Little Desert regions of the Mallee were the main source of brush in Victoria.²²³ Sources of naturally occurring material on private land are very limited due to clearing for agriculture.

In the 1980s a reduction in the South Australian supply of brush and an increase in demand for Melbourne fencing led to an increasing number of applications for broombush harvesting licences in Victoria. Subsequently more operators were licensed and larger amounts of broombush were being harvested in Victoria. A processing plant that manufactured fencing panels operated from Murtoa.

After considering the potential environmental impacts of harvesting and the nature conservation values of the areas concerned, the then Land Conservation Council recommended, in 1989, that substantial areas of the Mallee be included in national parks. As a result, the then government paid out the current operators by buying back their harvesting licences.

While broombush harvesting is still permitted outside the national parks, little, if any, is now undertaken in Victoria..

Current Trends

Supplies in Queensland were exhausted by the late 1980s, although at this time brush was still being cut in western New South Wales and Western Australia.²²⁴ In South Australia the availability of naturally occurring broombush is now also declining. Harvesting is considered a form of clearing under State vegetation clearing laws and permits are required. Fencing contractors, at times, have difficulty in obtaining sufficient brush to meet demand.²²⁵

Interest is developing in the cultivation of broombush.²²⁶ A number of trial plantings have been established in South Australia and Victoria. Research has been undertaken on yields under irrigation and under various planting densities, and for different fertiliser, weeding and harvesting regimes. These trials have demonstrated that it is possible to cultivate the plant. Harvesting regimes as low as every five years are feasible.²²⁷

The Committee inspected a small plantation of broombush at Stawell.²²⁸ The plantation, of about 1,000 irrigated plants, was two years old. It was expected to produce a commercial harvest in two to three years time. Other plantations are in Walpeup and Gippsland, the latter supplying material to the Melbourne market.

The planting of broombush has other potential benefits to landholders:

a) shelter - when used as part of shelter belts;

b) salinity control - the root systems of older plants will reduce groundwater recharge;

c) erosion control - it will grow on sandy soils;

d) land reclamation - it can grow in areas subject to salinity and water erosion; and

e) wildlife habitat.²²⁹

Sector Strengths and Challenges

Broombush harvesting enjoys a stable market for its product, a market that appears to be resource limited. As naturally occurring plants, especially those suitable for cutting, are now limited in availability, cultivation is increasingly attractive. Cultivation of broombush is feasible and, subject to the specific cost of establishment, yield generated and market price, has commercial potential.

It offers an economic use of otherwise unproductive land, and will grow without irrigation or application of fertiliser, albeit with lower yields. Greening Australia believes that:

There is an enormous potential for the incorporation of broombush production into the traditional Mallee and Wimmera annual cropping systems ... including the growing of broombush in `alley farming' layouts [that is, regular rows of shelter belts] ... Broombush is especially attractive when compared with timber crops because of the relatively short rotations (8 to 15 years).²³⁰

Seagrass

Seagrass is used as garden and horticultural mulch. It has also been used as an insulation material in the building industry.

There are a number of operators in Australia. There is little occurring in Victoria,²³¹ less than six operators in South Australia and approximately 80 in Tasmania.²³² All material harvested in South Australia and Victoria is beach cast, whereas harvesting of both beach-cast and detached floating material is permitted in Tasmania. No harvesting of attached (that is, live) material is currently permitted in Australia.

Sector Strengths and Challenges

Seagrass is a comparatively bulky and low-value product, with an array of alternative sources of mulch available.

Large-scale harvesting of seagrass is not encouraged in Victoria by the responsible agency, as "little is known regarding the extent of this resource, and recognising its broad habitat value, the Department of Natural Resources and Environment is taking a precautionary approach to management".²³³ Vehicle access on beaches, a necessary part of the harvesting operation, is very restricted in Victoria, principally due to potential dune erosion and recreational user impacts. Removal of beach-cast seagrass can also have an impact on other in-situ values of the material - habitat value (including for nesting of some bird species) and value as a dissipater of wave energy and thus beach erosion.