How much resource does one fence panel fabrication unit require to operate for a
year? Based on information obtained from Bowman Brush, the calculation is as
A single unit uses 15 tonnes green weight of material per week. This equates to a dry
weight of 10.5 t. At 34.1 kg/metre of 50 mm fence panel, this is 10,500 kg/34.1 = 308
m of fence, or 140 panels per week (28 panels/day). Data gained from the Baldivis
factory generally support this level of productivity. However, since these are key
The intake is 15 t/week or 3t/day of green Brushwood. In a full year of 250 working
days the intake is therefore 3 x 250 t = 750 t, and the annual production of 50 mm
fence panel is 28 x 250 x 2.2 = 15,400 m.
In practice, a machine in WA would probably produce a combination of fencing and
cladding, but as we do not have data on the proportion of the two products, it is not
possible to estimate how this would affect the output.
On these calculations, one machine working full time would easily supply about 60%
of the estimated WA market for 50 mm fencing. If the predictions by one local
supplier that the market will double in 12 months are anywhere near correct, then it
can be seen that the market could support a second part time machine within a year or
so. This does not allow for interstate sales, which are likely to be significant, in view
of the resource limitations in other States. An option that could be explored is to have
two machines at startup, with one optimised for 50 mm panel and the other producing
the thinner cladding.
It is reasonable to conclude that the WA market, supported by some interstate trade,
could easily support one fence panel machine in 2009, and probably a second one in
2010, depending on the level of interstate trade and the development of exports. In
view of the confidence of one manufacturer that exports can be increased, this would
appear to be a bright prospect for a WA factory, given its proximity to Asia and the
Middle East. Taking this into consideration, a requirement for 750 t/year of
Brushwood in 2009, increasing to 1500 t/year in 2010 seems a reasonable target. The
development of a good quality plantation resource in WA, combined with machine
harvesting, would assist the industry to contain costs and compete more effectively
with other fencing products.
The calculations set out above, considered with Figures 5 and 6, indicate that there is
unlikely to be sufficient Brushwood resource from private grower plantations in
Western Australia to supply a factory until 2012, whatever average plant weight is
used. If production is to begin before that time, the only way to provide 750
tonnes/year is to combine with the MIS resource (Figures 7 and 8). Even so, there
does not appear to sufficient resource to supply a second production unit, unless the
MIS resource is underestimated, until 2013, when there is a sudden and massive
increase in available resources. If the MIS company can provide more detailed
resource data, this problem may well disappear.
One option to allow an increase from one fencing unit in 2009 to two in 2010, is to
blend plantation and natural broom bush resources from the northeastern Wheatbelt
for a limited period. This would require a prior assessment of the level of resource
and agreement from property owners to grant access. However, there could also be
technical problems in doing this, since the older and slower grown natural resource is
likely to have different panelmaking characteristics from plantationgrown material,
and the panel machine needs to be optimised for the plantation resource.
After 2012 the very large area of Brushwood plantation becoming available from the
2007 and later plantings will ensure that the resource will not be the limiting factor.
The critical issue with regard to future supply to a brushwood factory is: what area of
Brushwood plantation is required to feed the plant. If the yield is 10 tonnes/ha, and
the initial requirement is 1500 tonnes/year, then 150 ha/year will provide sufficient
material for a twounit plant. If we have a harvest rotation of 6 years on average, then
the total area needed is 6 x 150 = 900 ha.
This estimate of plantation area applies to the effective area of plantation that meets
harvest quality standards.
This is necessarily a very crude estimate, as we do not have sufficient data on which
to construct a more soundly based figure. Even if the calculations are 50% in error, it
is difficult to see that a total area of plantation greater than about1400 ha can be
justified to supply the local market. If export of unprocessed Brushwood to the
Eastern States is successful, or an overseas market can be developed, then a greater
area may well be feasible.
Taking into account the difficulties of plantation establishment, the variability of
growth rates and the uncertainty of market development, a reasonable initial target for
private growers would be about 1000 ha of Brushwood plantation. Ideally, there
would be equal areas in each age class, so if the rotation length is 6 years, this means
about 170 ha a year. If the initial stocking is 3000/ha, then the annual seedling
requirement is 3000 x 170 = 510,000. Once the 1000 ha of suitable genetic material is
established, resprouting should provide sufficient ongoing resource until the stools are
exhausted and replanting is required.
For an individual grower, a minimum area of 2 ha per planting year is suggested as a
commercial enterprise. This would provide about 20 tonnes, i.e., a semitrailer load, at
Currently, only two Western Australian species are being planted by growers,
varieties. A draft field guide to the local Brushwood species is provided at Appendix
1 to assist in identification of these areas. At this stage these two species appear to be
the best local species for brushwood manufacture.
However, it is still not proven that the quality of the raw material is as good as the
M.uncinata utilised for brushwood in the Eastern States. Since it is possible that
locally produced brushwood could also be marketed in the Eastern States, is important
that material of equivalent or better quality is produced. The only way to establish
which species will meet the quality specification is to carry out field trials comparing
the best provenances of M.atroviridis and M.hamata, against selected good
provenances of M.uncinata from NSW. Preferably, such field trials should be
established at several sites on different soil types.
Future plantings of Brushwood need to be planned carefully. A grower must decide
whether it is to be a purely commercial plantation or if it is intended to serve some
landcare objective, as different species and a different approach to management may
be involved. In general, yields from land affected by waterlogging or salinity will be
low and the species used may not be suitable for brushwood.
The experience of planting over the last few years on Western Australian farms has
given a sound basis for future plantation establishment. Useful advice to growers is
given by Scarvelis (2003), Robinson and Emmott (2005) and by Avongro (2007).
Direct seeding has been shown to be a risky approach as success is critically
dependent on seasonal conditions. The use of nurserygrown seedlings is now
common. Given that genetic improvement is a critical move over the next few years,
and the use of selected nursery stock is the most efficient way of achieving this, no
change in this approach is foreseen in the immediate future. Care needs to be taken to
use good quality seedlings about 30 cm in height and to plant in June/July to ensure
that they become well established before the dry season. Shallow soils subject to
waterlogging should be avoided
So far, the growers have been able to benefit from the provision of subsidised
seedlings, but it is uncertain that this will continue, and more emphasis will be laid on
good establishment procedures (eg, as described by Robinson and Emmott) to ensure
high seedling survival and good early growth. A high initial survival is important to
avoid the necessity to refill blanks in subsequent years. A plantation with evensized
plants is important for efficient machine harvesting.
Planting espacement is a compromise between cost, control of weeds and individual
plant growth rate. Closer planting encourages the production of erect, straight, stems
that are required for brushwood manufacture. An initial plant stocking of 3000 stems
per hectare is probably a good compromise. Good weed control, especially of any
woody weeds, is essential to concentrate the productive potential of the site on the
Brushwood crop and to avoid difficulties in machine harvesting. Grower experience
so far indicates that added fertiliser has little value.
Instances of insect attack have been observed by some growers. The main species
involved so far have been waxy scales, grasshoppers and black beetles. Since we are
dealing with a native plant species the possibility of an outbreak of a native insect or
disease well adapted to the crop plant must always be borne in mind. However, there
does not appear to be any insect or disease that is particularly damaging to Melaleuca
species at this stage.
It seems to be accepted in the Eastern States that the regrowth after cutting provides
better quality material for brushwood manufacture. If this is so, cutting back at an
early age offers:
more clear, or
evening out the annual harvest by agreement among growers.
improved if the cut stems are crushed in some way. Second growth is also said to be
more vigorous, there is a proliferation of shoots and shoot straightness is better.
Whether this applies the local species is unknown.
The estimated yield from first rotation crops, harvested at age 6, is about 10
tonnes/ha, although some early harvesting trials have yielded better figures. Second
rotation crops should yield at least 12 tonnes/ha, on Eastern States experience.
It is uncertain, at this stage, whether the plantations will be harvested mechanically or
by hand. If mechanical harvesting proves to be feasible, the plantation needs to be
managed to facilitate machine operation by eliminating weeds and making sure the
ground is level. Level ground and a crop of uniform size should assist the machine to
maintain the proper cutting height, which will be an important requirement for a high
quality product. Rabbit warrens could be particularly damaging to a harvester.
Hand harvesting has the advantage of automatic deletion of unsuitable parts of
individual plant stems as the cutter progresses. However, the availability of labour for
this arduous task is likely to be a problem. Whichever method of harvesting is used,
attention needs to be given to streamlining the steps in handling to minimise costs.
The fact that growers are dealing with a native species has a complication in that
harvesting is affected by the provisions of the Wildlife Conservation Act. Under the
Act, a licence to harvest required form the relevant Government agency, currently the
Department of Conservation and Environment. To facilitate acceptance by the agency
that the Brushwood crop is actually a plantation established for the purpose of
commercial exploitation, good records and a simple management plan will be useful.
A draft management plan for this purpose is provided at Appendix 3.
It will be clear from much of the foregoing that there remain many unresolved issues
relating to the use of Brushwood by growers in Western Australia, whether it be the
production of high quality material for commercial use, or the utilisation of
Brushwood for addressing landcare problems.
The primary issues at this time appear to be as follows:
Identification, selection and propagation of germplasm that has desirable
may well be a feasible technique for propagation of preferred genotypes.
Identification of the best soil types for commercial Brushwood production and
good resprouting ability.
Determining the optimum treatment for ensuring good regrowth after
common with most native Australian plants, Melaleuca species are known to
form ectomycorrhizal (ECM) and vasculararbuscular mycorrhizal (VAM)
associations. Lack of the correct mycorrhizae may well be restricting the
growth of Brushwood on some sites.
An assessment of each plantation considered to have commercial potential
plantation assessment and also more complete survival data.
Information on these issues needs to be gathered in a systematic way and recorded in
a safe location, followed by dissemination to growers. The first step is to carry out a
careful evaluation of grower experience so far, then develop an agreed research plan.
Some aspects of research and development can be handled by growers themselves, if
they are provided with suitable research plans and materials, but others, such as the
ECM/VAM work, are more suited to a University Honours project. An overall
coordinator of the R&D program is required and this role might be fulfilled by
Avongro or by the Avon Catchment Council, which might also act as a data storage
centre. An ongoing coordination role is vital in this situation.
The Brushwood plantation industry has many problems to overcome if it is to be
firmly established in Western Australia. To achieve a sustainable and commercially
viable product the growers need to address the following issues:
by potential harvest year, against an agreed and suitable product specification.
This is urgent if growers are to be in a sound position to negotiate with a
potential manufacturer in WA.
Assess the feasibility of obtaining Brushwood resource from natural stands on
a brushwood factory.
Obtain more comprehensive data on yield per plant to refine resource
potential for integrating MIS and grower harvest plans. This would require a
representative group to be able to negotiate on behalf of growers.
Explore avenues for brushwood factory development, considering location in
as sales of unprocessed Brushwood.
Use sales data to plan future investments in brushwood factory expansion and
process to reduce costs.
Research and development
Begin a research program that will deliver information on growth rates on
quality sites for M.uncinata in the Eastern States.
Support research to determine the value of mycorrhizal inoculation in the
and from this determine which species/provenance best meets manufacturers’
requirements, as well as having desirable growth and resprouting
Establish a seed production area to supply certified best quality seed to
AVONGRO Wheatbelt Tree Cropping Incorporated, (2007). Brushwood Economics.
Broombush Industry Group (2004). Broom Bush Industry Strategic Plan 20052010.
Brophy, J.J.,R. J. Goldsack, L.A.Craven and W.O’Sullivan. (2006). An Investigation
of the Leaf Oils of the Western Australian Broombush Complex (Melaleuca uncinata
sens. Lat.) (Myrtaceae).
Craven, L.A., B.J.Lepschi, L.Broadhurst and M.Byrne. (2004). Taxonomic revision of
the broombush complex in Western Australia (Myrtaceae, Melaleuca uncinata s.l.)
Australian Systematic Botany 17 (3):255271.
Doran, J.C., Baker, G.R., Murtagh,G.J. and I.A.Southwell. (1996). Breeding and
selection of Australian Tea Tree for improved oil yield and quantity. Final Report for
Rural Industries Research and Development Corporation.
McKelvie, J., J. Bills and A. Peat. (1994). Jojoba, Blue Mallee and Broombush
Market Assessment and Outlook. ABARE Research Report 94.9.
Robinson, C, and T. Emmott. (2005). Growing Broombush: for Fencing Products on
Cleared Farmland in Southern WA. Greening Australia WA Inc.
Scarvelis, J. (2003). Broombush for brush fencing. Fact Sheet 15/01. Primary
Industries and Resources South Australia, 5 pp.
The following persons are thanked for providing valuable comments and advice :
Helen Job, Monica Durcan, Wayne O’Sullivan, Georgie Troup, Tim Emmott, Peter
Grimes, David Groom, Shane Davey, Stephen Darley, Steve Mant, Maitland Davey,
Neville Turner, Clive Bowman, Dr Jon Majer.
1. Field guide
2. Comparison of percent oil content of WA Melaleuca species against the ISO
standard for tea tree oil
3. Template for Brushwood Plantation Management Plan
1. Bark peeling in large curls, papery
1. Bark not peeling in large curls
2. Leaf blades flat
3. Grey foliage, short leaves, shrub to 2.5 m tall
4. Green foliage
5. Shrub 2.2 m tall, leaves thin, stamens 34.5 mm long
5. Shrub 6 m tall, leaves thick, stamens 4.29.2 mm long
2. Leaf blades not flat
3. Large oil glands in rows
4. Quadrate leaf section, papery bark
4. Leaf section dumbbellshaped, fibrous bark
3. Oil glands scattered
4. Desert species
4. Not desert species
5. Leaf blades narrow, less than 1 mm
5 leaf blades>1 mm wide
6. Dark green foliage, cylindrical fruit
6. Light green foliage, globular fruit
7. Style > 6 mm
7. Style < 6 mm
1.127.7 0.341.6 1.6
A wellmaintained description and record of plantation activities will assist a grower
to keep systematic records during plantation growth, and to obtain a licence to harvest
from the Department of Environment and Conservation when the time comes to
utilise the Brushwood. A licence is required under the Wildlife Conservation Act for
each year that harvesting takes place, at a cost of $25/year.
1. Plantation owner details
Location of Plantation: (e.g. Avon Location 1163, location map attached)
2. Plantation description
Previous natural vegetation, if known:
Year of planting:
Species/ number of seedlings planted (e.g., 12,000 M.atroviridis, 5,000 M.hamata):
Seed source/provenance, if known:
Survival % at year 1 after planting:
3. Management regime
Preplanting cultivation/ weed control:
Plant spacing within rows:
The following should be recorded as the activity takes place.
Weed control measures: (e.g., spot application of Roundup to control thistles)
Pest control measures:
Fire protection measures:
Intended year of harvest:
Before harvesting takes place application must be made to DEC for a licence to
harvest. The application should include a copy of the management plan, with
management data filled in.
Date the application for a producers/nurserymans licence was sent to DEC:
Date that the licence was received from DEC:
DEC file number:
Date(s) of plantation harvest:
DEC licence requirements met: