sustainable forest management - Forestry Tasmania

Environmental quality monitoring
Air monitoring
Planned burning is undertaken throughout Tasmania on
private land and state forests each autumn. Burning is
dispersed and only a limited number of operations occur
on any one-day. This burning is important to reduce the
fuel hazard resulting from logging residue and to create
a seedbed for eucalypt regeneration. Eucalypt seeds and
seedlings need a mineral soil seedbed, abundant sunlight
and reduced competition from other plants to establish
and grow. In drier eucalypt forest, burning is undertaken
to remove the residues remaining after harvesting so as to
reduce the fuel load and fire hazard.
Unfortunately, smoke is an inevitable product of this
burning process. However, unlike the smoke from summer
bushfires, a number of pro-active management options are
available to assist in minimising the effects of this smoke
on local communities. One of these options includes
conducting burning operations on days where forecasted
weather conditions indicate the smoke will be dispersed
away from settled areas. To keep stakeholders informed
about burning locations relevant information is provided
through the Tasmanian planned burn website (www.
plannedburnstas.com.au).
National Environment Protection Measure (NEPM)
monitoring of air quality occurs at Hobart, Launceston and
Judbury. DPIW is responsible for monitoring the Hobart
and Launceston stations, while Forestry Tasmania manages
the Judbury site. The maximum concentration guideline
for particles is 50µg/m 3 (PM 10
), averaged over a 24-hour
period. This is based on a level above which impacts on
human health may be experienced. Measurements are
taken at ground level. During 2007/08 the NEPM standard
as measured by the Launceston monitoring station was
exceeded three times, however, through correlation with
the days on which Forestry Tasmania was conducting high
and low intensity burns, it is unlikely that Forestry Tasmania
contributed to the exceeded levels.
In the autumn of 2008 smoke management was complicated
by weather conditions that saw the overly dry conditions
change to overly wet, followed by a succession of high
pressure systems that formed to the west and crossed the
State in close succession. This brought sunny, still days and
cold nights with strong temperature inversions.
Landowners across the State used the calm period to
undertake fuel reduction burning, and this, combined with
burning undertaken by the forest industry, generated heavy
smoke loads in susceptible parts of the State including the
Tamar and lower Derwent valleys. The smoke produced
by this burning was exacerbated by smoke produced by
widespread burning in Victoria, which was carried at low
level across Tasmania by the northerly winds associated
with the high pressure systems. In consequence, Forestry
Tasmania suspended its autumn burning program for several
days after 22 April, to allow an opportunity for conditions to
improve.
Table 12. Water testing associated with spray operations
Water quality
Forestry Tasmania has had a formal water quality sampling
system in place since 1993. The system has been continually
refined in the past decade based on operational experience
and research findings. The use of pesticides and fertilisers
must comply with the environmental protection measures
prescribed in the Forest Practices Code. Section E2 of the
code contains specific prescriptions covering watercourse
protection. Forestry Tasmania’s water sampling policy states
that water sampling is to be done following the broad scale
application of pesticides and fertilisers. Three sets of water
samples are taken: one sample set prior to application to
establish any background contamination; the second after
the application; and the third set of samples is taken following
the first significant rain event after spraying has occurred to
detect any contamination due to run-off and leaching.
The health and guideline values for drinking water prescribed
by the National Health and Medical Research Council
(NHMRC) are used as the standards for determining the
need for investigation and corrective action when pesticides
are detected in water samples. Where no guideline values
are prescribed for particular pesticides, Forestry Tasmania
uses any detection of the pesticide in water samples as the
trigger for investigation. For the 2007/08 spraying season,
139 samples were submitted for chemical analysis with no
samples returning a positive result.
2003/2004 2004/2005 2005/2006 2006/2007 2007/2008
Number of samples associated with chemical spraying operations 361 410 635 302 139
No. of detections and percentage of no chemical detections (15) 95.8% (3) 99.3% (1) 99.8% (0) 100% (0) 100%
against ADWG Guideline Value 1 for chemical residues 2
1. Australian Drinking Water Guidelines Health Value or any detection where no value indicated.
2. Measured by DPIW testing laboratory.