❓ Hon Lynn MacLaren questions the scientific basis for the Department of Parks and Wildlife's 200,000-hectare prescribed burning target. The Minister provides a detailed historical and scientific justification for the target, referencing research and practical considerations.
AnsweredQoN 547Legislative Council
QuestionView source ↗
DEPARTMENT
OF PARKS AND WILDLIFE — PRESCRIBED BURNING PROGRAM
547. Hon LYNN MacLAREN to the
minister representing the Minister for Environment:
(1) Can the
minister please table or refer me to documents outlining the scientific basis
for the figure of 200 000 hectares that has been set as the Department of Parks
and Wildlife's annual prescribed burning target?
(2) Is there
is a measurable and proven correlation between the number of hectares
prescribed-burnt statewide and the number of out-of-control fires?
(3) What are the department's criteria for measuring
the success of its prescribed burn programs?
(4) If no such criteria exist, why not?
OF PARKS AND WILDLIFE — PRESCRIBED BURNING PROGRAM
547. Hon LYNN MacLAREN to the
minister representing the Minister for Environment:
(1) Can the
minister please table or refer me to documents outlining the scientific basis
for the figure of 200 000 hectares that has been set as the Department of Parks
and Wildlife's annual prescribed burning target?
(2) Is there
is a measurable and proven correlation between the number of hectares
prescribed-burnt statewide and the number of out-of-control fires?
(3) What are the department's criteria for measuring
the success of its prescribed burn programs?
(4) If no such criteria exist, why not?
AnswerView source ↗
I thank the member for some notice of this question. The
answer is actually quite lengthy, and it might save the house whole lot of time
if I asked to have it incorporated into Hansard .
Leave granted.
The
following material was incorporated —
I thank the Hon. Member for
some notice of this question.
(1) Broad area prescribed burning of the south-west
forests became formal policy in the mid-1950s. Prescribed burning was expanded
following the 1961 Dwellingup bushfires and subsequent Royal Commission. The
figure of 200,000 hectares was developed in the late 1970s and early 1980s by
Departmental fire managers. It took into consideration the average number of prescribed
burning opportunities that could be expected to present themselves, the
resources available to undertake prescribed burning work and judgement as to
how much of the landscape needed to be maintained in a low fuel condition to
reduce the risk of landscape scale bushfire occurrence. The figure of 200,000
hectares was formally adopted following a submission by the Department to the
Ministerial Review Panel in 1994.
The
effectiveness of these judgements was tested in 2009 by a study in the
south-west forests undertaken by Dr Matthias Boer et al that examined the
historical occurrence of bushfire and prescribed fire over a 52 year period to
quantify the impact of prescribed burning on the incidence, extent and size
distribution of wildfires. This study determined that prescribed fire
treatments had a significant effect on bushfire up to six years after
treatment. It also demonstrates that over the 52 years from 1953 to 2004, with
peak activity in the 1960s and 1970s, prescribed burning of about eight per cent
of the landscape each year significantly reduced the incidence and extent of
unplanned bushfires. Given that there is approximately 2.6 million hectares of
forested estate under Departmental management in the south-west, eight per cent
of this equates to treating approximately 208,000 hectares per annum. Achieving
this degree of treatment each year will facilitate approximately 45 per cent of
the forested estate to carry fuel loads that are less than six years old.
(2) The research of Boer et al 2009 has provided a
reliable correlation between the extent of prescribed fire treatment and
bushfire extent in the forests of the south-west.
Monitoring
in the Kimberley as part of the Kimberley Science and Conservation Strategy is
underway to determine the relationship between the extent of late dry season
(high intensity) bushfires and the extent of prescribed burning undertaken in
the early dry season (low intensity) on the biota. The aim is to decrease the
amount of high intensity fire by 40 per cent by utilising low intensity
prescribed fire treatments. Results of this work are pending.
Reliable
correlations are not available for rangeland areas as the Department's
involvement in fire management in these areas is relatively recent and the
extent of prescribed fire operations in the past has been limited to localised
areas.
(3) The Department utilises the 200,000 hectare target
as a performance measure and also assesses the contribution of individual
prescribed burns to minimising the impact and/or size of bushfires.
(4)
See (3).
answer is actually quite lengthy, and it might save the house whole lot of time
if I asked to have it incorporated into Hansard .
Leave granted.
The
following material was incorporated —
I thank the Hon. Member for
some notice of this question.
(1) Broad area prescribed burning of the south-west
forests became formal policy in the mid-1950s. Prescribed burning was expanded
following the 1961 Dwellingup bushfires and subsequent Royal Commission. The
figure of 200,000 hectares was developed in the late 1970s and early 1980s by
Departmental fire managers. It took into consideration the average number of prescribed
burning opportunities that could be expected to present themselves, the
resources available to undertake prescribed burning work and judgement as to
how much of the landscape needed to be maintained in a low fuel condition to
reduce the risk of landscape scale bushfire occurrence. The figure of 200,000
hectares was formally adopted following a submission by the Department to the
Ministerial Review Panel in 1994.
The
effectiveness of these judgements was tested in 2009 by a study in the
south-west forests undertaken by Dr Matthias Boer et al that examined the
historical occurrence of bushfire and prescribed fire over a 52 year period to
quantify the impact of prescribed burning on the incidence, extent and size
distribution of wildfires. This study determined that prescribed fire
treatments had a significant effect on bushfire up to six years after
treatment. It also demonstrates that over the 52 years from 1953 to 2004, with
peak activity in the 1960s and 1970s, prescribed burning of about eight per cent
of the landscape each year significantly reduced the incidence and extent of
unplanned bushfires. Given that there is approximately 2.6 million hectares of
forested estate under Departmental management in the south-west, eight per cent
of this equates to treating approximately 208,000 hectares per annum. Achieving
this degree of treatment each year will facilitate approximately 45 per cent of
the forested estate to carry fuel loads that are less than six years old.
(2) The research of Boer et al 2009 has provided a
reliable correlation between the extent of prescribed fire treatment and
bushfire extent in the forests of the south-west.
Monitoring
in the Kimberley as part of the Kimberley Science and Conservation Strategy is
underway to determine the relationship between the extent of late dry season
(high intensity) bushfires and the extent of prescribed burning undertaken in
the early dry season (low intensity) on the biota. The aim is to decrease the
amount of high intensity fire by 40 per cent by utilising low intensity
prescribed fire treatments. Results of this work are pending.
Reliable
correlations are not available for rangeland areas as the Department's
involvement in fire management in these areas is relatively recent and the
extent of prescribed fire operations in the past has been limited to localised
areas.
(3) The Department utilises the 200,000 hectare target
as a performance measure and also assesses the contribution of individual
prescribed burns to minimising the impact and/or size of bushfires.
(4)
See (3).
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