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Clearing Trees on Farms in Australia
Bill McCormick
Science, Technology, Environment and Resources Group
Introduction
The loss of native forest and woodland area on farms is increasingly
seen as a problem and programs such as Save the Bush, One Billion Trees
and Corridors of Green have been established to halt such loss and
replace the native vegetation. The Government estimated that, since 1989,
these programs have resulted in the establishment and protection of 680,000
hectares (ha) of vegetation throughout Australia. (1) However during the
first four years of that period (1989-1993) approximately 2 million ha
of native vegetation was cleared for agricultural purposes. (2)
Native vegetation provides a number of ecological, economic, cultural
and social benefits. These include protecting water resources; maintaining
biodiversity; providing a carbon sink to absorb greenhouse gases; providing
shelter to stock; contributing to soil conservation; maintaining lower
water tables and preventing salinity; providing places for tourism and
recreation; and providing timber and non-wood products such as honey and
flowers. The large-scale clearance of native vegetation leads to a number
of problems such as dryland salinity, rising water tables, decline of
biodiversity leading to extinctions, habitat loss and fragmentation. It
also contributes to an increase in greenhouse emissions and reduction
of regional rainfall. (3)
Past Clearing
The significant historical clearing of native vegetation for pastoral
and agricultural purposes on Australian farms is still occurring, primarily
in two States, NSW and Queensland. Estimates of the rate of land clearing
have been made with the figure of 500 000 hectares (ha) per year given
as an indicative rate of natural vegetation for agricultural purposes
in Australia for the period 1983-1993. Data on land clearing has been
produced from an analysis of Landsat Satellite imagery for an area of
south-central Queensland which represents 4% of Queensland. Over the period
1972 and 1990, over one million ha was cleared to some extent, with an
average annual clearing rate of 43 000 ha, about double the clearing rate
of the previous 100 years. The Queensland Department of Lands issued permits
(valid for five years) to clear 684 967 ha of virgin native vegetation
and 391 730 ha of regrowth on leasehold land in 1994. It should be noted
that not all areas permitted to be cleared will actually be cleared.
Extent of Remnant Vegetation on Farms
A survey of trees on Australian farms by ABARE in 1993/94 produced some
interesting results. It defined native forests as trees or regrowth which
were higher than 2 metres with a canopy cover of 50-100%. Native woodland
was defined as trees and regrowth higher than 2 metres, with a canopy
cover of 10-50% or with 10 large trees or 40 small trees per hectare (ha).
The survey reported that 81% of Australia's wheat-sheep zone (areas of
inland Australia most suitable to broadacre cropping) farms and 68% of
Australia's high rainfall zone farms still contain areas of native forests
and woodlands. (4) The extent in percentage terms and actual area of remnant
native vegetation varies significantly between the States and between
holdings in the pastoral (arid and semi arid) zone, the wheat-sheep zone
and the high rainfall zone. Only 4% of South Australia's wheat-sheep zone
farms still retain native forests while 43% of Queensland's wheat-sheep
zone farms support areas of native forests. The reasons that a significant
number of farms have no area of trees or woodland include clearing but
also the fact that some farms were established on native grasslands.
The average area of native forests and woodlands on Australian farms
is significant, 348 ha for the wheat-sheep zone and 163 ha for the high
rainfall areas, but these are up small proportion of the area of these
farms, 19.6% and 9.3% respectively (see Table 1). Native forests make
up a smaller component of this total than native woodland. 5.9% (49 ha)
of the area of Australian farms in the high rainfall zone are covered
by native forests with the percentage cover varying from 1.6% (5 ha) for
Victorian farms to 7.7% (201 ha) for Queensland farms.
Proposed Clearing
The survey also found out the landholders's intentions to clear native
forest and woodlands over the five year period 1994/5-1998/99. As mentioned
previously Queensland and NSW are the states where farmers are planning
the greatest amount of clearing native vegetation over this period. 27%
of Queensland farmers in the wheat-sheep zone, 23% of Queensland farmers
in the pastoral zone and 12% of NSW farmers in the high rainfall zone
planned to clear native forests and woodlands. Figure 1 shows the state
proportions of planned clearing of native vegetation. The pastoral zone
and the wheat-sheep zone of Queensland are where the greatest average
area per farm of native vegetation is intended to be cleared over the
five year period, 696 ha in the pastoral zone and 186 ha in the wheat-sheep
zone. The figure for the wheat-sheep zone in Queensland represents one
quarter of the remaining native forests on each property. Figure 2 shows
the total area that is to be cleared over the five year period with 2
886 000 ha intended to be cleared in Queensland and 283 000 ha intended
to be cleared in NSW.
Clearing Controls
Clearing controls vary between the States; they are quite comprehensive
in South Australia, Victoria, Western Australia and the ACT but limited
in Tasmania and the Northern Territory. (5) New procedures are being implemented
in Queensland (draft State guidelines on tree clearing) and NSW (State
Environment Planning Policy No 46 for the protection and management of
native vegetation) which have been modified due to pressure from landholders.
While it is not yet clear to what extent, the new clearing controls and
guidelines in these two states will influence the final clearance outcome.
Endnotes
- Senator J Faulkner, Media Release, 24 January 1996
- National Greenhouse Gas Inventory. 1994. National Greenhouse Gas
Inventory, 1988 and 1990 DEST Canberra
- Biodiversity Unit, 1995. Native vegetation clearance, habitat
loss and biodiversity decline. Biodiversity Series, Paper No 6.
DEST, Canberra
- Wilson et al, 1995. Trees on Farms. Survey of trees on Australian
farms: 1993-94 ABARE Research Report 95.7 ABARE, Canberra
- DEST, 1995. Clearing Controls in the State and Territories
Address to the National Greenhouse Advisory Committee 5/10/95.
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