Fire is important to maintain the diversity of native plants and animals. It plays a vital role in renewing ecosystems, releasing
nutrients and encouraging seed germination. However, if fire is used inappropriately, plant and animal species decline and can become
extinct. Both too frequent and too infrequent burning can cause problems in fire-adapted ecosystems. Prevention of fire-driven extinction
of fauna and flora populations caused by too frequent fires requires consideration as does the need to accommodate fire-enhanced recruitment
of many plant species and the benefits to fauna brought by fire.
DERM Fire Management Recommendations by Ecosystem at Long Grass Nature Refuge
12.8.21 Semi-evergreen vine thicket with Brachychiton rupestris on Cainozoic igneous rocks
Do not burn deliberately. Protection
relies on broad-scale management of surrounding country with numerous small fires throughout the year so that wildfires will be very
limited in extent. May need active protection from wildfire in extreme conditions or after prolonged drought. Planned burns should
not create a running fire into vine forest. Ensuring conditions of good soil moisture and moisture of litter in surrounding communities
will limit fire behaviour/intensity. ISSUES: Fire sensitive and not normally flammable. Some preliminary work (Tran et al. 2008) suggests
rainforest seedling germination from planned burning activities will assist the establishment of seedlings in newly burnt areas, especially
due to smoke. There may be issues with lantana and other weeds from fire and other disturbance. Remnants may be limited by frequent
fire at the margins; this requires further research.
12.9-10.15 Semi-evergreen vine thicket with Brachychiton rupestris on sedimentary rocks
Do not burn deliberately. Protection
relies on broad-scale management of surrounding country with numerous small fires throughout the year so that wildfires will be very
limited in extent. May need active protection from wildfire in extreme conditions or after prolonged drought. Planned burns should
not create a running fire into vine forest. Ensuring conditions of good soil moisture and moisture of litter in surrounding communities
will limit fire behaviour/intensity. ISSUES: Fire sensitive and not normally flammable. Some preliminary work (Tran et al. 2008) suggests
rainforest seedling germination from planned burning activities will assist the establishment of seedlings in newly burnt areas, especially
due to smoke. There may be issues with lantana and other weeds from fire and other disturbance. Remnants may be limited by frequent
fire at the margins; this requires further research.
12.8.14 Eucalyptus eugenioides, E. biturbinata, E. melliodora open forest on Cainozoic igneous rocks
Summer to winter. INTENSITY:
Plan for low to moderate. Unplanned occasional high intensity wildfire will occur. INTERVAL: 4-8 years maintains a healthy grassy
system. 8-20 years for shrubby elements of understorey. STRATEGY: Aim for 40-60% mosaic burn. Needs disturbance to maintain RE structure
(eucalypt overstorey with open understorey of predominantly non-rainforest species). Any moist sclerophyll that is relatively open
with a mixture of grasses and shrubs should be a priority for fire management to retain RE structure. a. Aim for 40-60% mosaic burn.
Burn with soil moisture and with a spot ignition strategy so that a patchwork of burnt/unburnt country is achieved. ISSUES: Typically
lower rainfall than other moist RE types, but prefers sheltered slopes and gullies where it maintains moist environment. Frequent
fire is needed to maintain understorey integrity, keeping more mesic species low in the profile of the understorey so that other species
can compete (Campbell and Clarke 2005). A grassy system is especially important for species such as the eastern bristlebird (D. Stewart
in Recovery Plan) and its habitat. It is essential that wildfires are not the sole source of fire in this ecosystem. High intensity
fires occur periodically through time, however frequent low to moderate intensity fires will create the disturbance required to keep
the understorey diverse. Wildfire should be used as a catalyst to recreate the required frequency of disturbance. It is likely that
mesic species will germinate after a high intensity fire and another fire soon after will be required (as recommended by Watson 2007).
This RE contains a number of rare and threatened plant species (e.g., Plectranthus suaveolens and Sophora fraseri) which require appropriate
fire management. Spring burns (traditionally used in SEQ ecosystems) have an associated risk due to changing weather conditions post-burn.
a. The fire regime should maintain a mosaic of grassy and shrubby understoreys. Control of weeds is a major focus of planned burning
in most areas. Careful thought should be given to maintaining ground litter and fallen timber habitats by burning only with sufficient
soil moisture. Burning should aim to produce fine scale mosaics of unburnt areas. Variability in season and fire intensity is important,
as well as spot ignition in cooler or moister periods to encourage mosaics. Spring burns (traditionally used in SEQ ecosystems) have
an associated risk due to changing weather conditions post-burn. The fire interval recommendation provides a guide to burning frequency
and should be adjusted according to the ‘reading of country’ and observed ecosystem health in relation to fire.
12.8.17 Eucalyptus crebra, E. melanophloia woodland on Cainozoic igneous rocks
Summer to late-autumn. INTENSITY: Low. INTERVAL: 3-6
years. STRATEGY: Aim to burn 40-60% of any given area. Spot ignition in cooler or moister periods encourages mosaics. ISSUES: Control
of weeds is a major focus of planned burning in most areas. Maintain ground litter and fallen timber habitats by burning only with
sufficient soil moisture. Burning should aim to produce fine scale mosaics of unburnt areas. Spring burns (traditionally used in SEQ
ecosystems) have an associated risk due to changing weather conditions post-burn. The fire interval recommendation provides a guide
to burning frequency and should be adjusted according to the ‘reading of country’ and observed ecosystem health in relation to fire.
12.9-10.19 Eucalyptus fibrosa subsp. fibrosa open forest on sedimentary rocks
Summer to winter. INTENSITY: Low to moderate. INTERVAL:
4-25 years. STRATEGY: Aim for 40-60% mosaic burn. Burn with soil moisture and with a spot ignition strategy so that a patchwork of
burnt/unburnt country is achieved. ISSUES: The fire regime should maintain a mosaic of grassy and shrubby understoreys. Control of
weeds is a major focus of planned burning in most areas. Careful thought should be given to maintaining ground litter and fallen timber
habitats by burning only with sufficient soil moisture. Burning should aim to produce fine scale mosaics of unburnt areas. Variability
in season and fire intensity is important, as well as spot ignition in cooler or moister periods to encourage mosaics. Spring burns
(traditionally used in SEQ ecosystems) have an associated risk due to changing weather conditions post-burn. The fire interval recommendation
provides a guide to burning frequency and should be adjusted according to the ‘reading of country’ and observed ecosystem health in
relation to fire.
12.9-10.3 Eucalyptus moluccana on sedimentary rocks
Summer to winter. INTENSITY: Low to moderate. INTERVAL: 4-25 years. STRATEGY: Aim
for 40-60% mosaic burn. Burn with soil moisture and with a spot ignition strategy so that a patchwork of burnt/unburnt country is
achieved. ISSUES: The fire regime should maintain a mosaic of grassy and shrubby understoreys. Control of weeds is a major focus of
planned burning in most areas. Careful thought should be given to maintaining ground litter and fallen timber habitats by burning
only with sufficient soil moisture. Burning should aim to produce fine scale mosaics of unburnt areas. Variability in season and fire
intensity is important, as well as spot ignition in cooler or moister periods to encourage mosaics. Spring burns (traditionally used
in SEQ ecosystems) have an associated risk due to changing weather conditions post-burn. The fire interval recommendation provides
a guide to burning frequency and should be adjusted according to the ‘reading of country’ and observed ecosystem health in relation
to fire.
12.9-10.6 Acacia harpophylla open forest on sedimentary rocks
Various, avoiding the hottest time of the year. Late summer to mid-winter
is typically suitable for planned burns. INTENSITY: Low to moderate. INTERVAL: 6-10 years. STRATEGY: Planned burns should be used
to protect scrubs at their margins from fire incursion and to reduce fuel loads in order to prevent the spread of wildfire. Burn less
than 10% in any year. Small and spaced spot fires lit on the edge of remnants should be used to draw fire away from the perimeter
of remnants using prevailing wind conditions. ISSUES: This vegetation primarily requires protection from fire, however carefully managed
low intensity fires will be useful in buffering remnants from surrounding vegetation and reducing fuel loads, leading to overall protection
of the RE from wildfire. Moderate fires may assist in the regeneration of hard-seeded species and occasional high intensity fires
may enhance acacia regeneration. Frequent fires may eliminate acacia, casuarina and other obligate seeding species. Remnants can be
degraded by wildfire and planned burns if implemented inappropriately. The fire interval recommendation provides a guide to burning
frequency and should be adjusted according to the ‘reading of country’ and observed ecosystem health in relation to fire.
12.9-10.7 Eucalyptus crebra woodland on sedimentary rocks
Summer to winter. INTENSITY: Low to moderate. INTERVAL: 4-25 years. STRATEGY:
Aim for 40-60% mosaic burn. Burn with soil moisture and with a spot ignition strategy so that a patchwork of burnt/unburnt country
is achieved. ISSUES: The fire regime should maintain a mosaic of grassy and shrubby understoreys. Control of weeds is a major focus
of planned burning in most areas. Careful thought should be given to maintaining ground litter and fallen timber habitats by burning
only with sufficient soil moisture. Burning should aim to produce fine scale mosaics of unburnt areas. Variability in season and fire
intensity is important, as well as spot ignition in cooler or moister periods to encourage mosaics. Spring burns (traditionally used
in SEQ ecosystems) have an associated risk due to changing weather conditions post-burn. The fire interval recommendation provides
a guide to burning frequency and should be adjusted according to the ‘reading of country’ and observed ecosystem health in relation
to fire.
12.3.7 Eucalyptus tereticornis, Melaleuca viminalis, Casuarina cunninghamiana fringing forest
Avoid intentionally burning this fringe
vegetation. Burn surrounding ecosystems in conditions that would minimise fire incursion. ISSUES: Protection relies on broad-scale
management of surrounding country with numerous small fires throughout the year so that wildfires will be very limited in extent.
However, fire exclusion is not necessary. Casuarina equisetifolia is very sensitive to fire and germination after fire is typically
very low or negligible. Triggers unrelated to fire appear to maintain a healthy ecosystem. Issues with lantana and other weeds may
result from fire and other disturbance.
Fire and nature Conservation
A well designed fire management plan needs to minimise the risk to life and property whilst at the same time enhancing biodiversity.
Fire intervals that may be ideal for ecological purposes may be longer than those appropriate for property protection. In addition,
ideal fire intervals for different ecosystems may differ. It is thus necessary to identify the different and map the ecosystems
present on the property and design a fire schedule appropriate for each area.The fire plan should also identify actions
to be taken in the event of an unplanned wildfireas well as specifing equipment maintenance schedules to ensure that appropriate
responses can be taken when required.
For each area identify the frequency, the extent, the intensity and the season of
planned burns.
Too frequent burning
Plants need time to recover from fire, to flower and produce enough seed to replace those lost to fire. Shrub
species can be lost if fires are too frequent. This makes the vegetation more open and unsuitable for birds and animals that need
undergrowth for nesting and shelter, and those that rely on shrub flowers and seeds for food. If regular burning always occurs in
the same season, some species of plants and animals could be reduced in numbers if the fire corresponds with their breeding season.
Too
infrequent burning
If fire is too infrequent, short lived plants that only regenerate after fire may become locally extinct.
Understory plants can take over a forested area and cause a shift in resident animal and bird species. A dense understory can suppress
regeneration of eucalypts which in turn reduces the available food sources for honeyeaters and flying-foxes.
As a rule of thumb for
burning frequency:
-
rainforest, vine scrub and creeksides should not be burnt,
-
open eucalypt forest with a shrubby understory 7-25
years
-
open eucalypt forest with a grassy understory 3-6 years
Patch or mosaic burning is recommended. Unburnt patches provide a place for animals to shelter during the fire, a food source after
the fire, a seed source for plant regeneration and a base from which animals can recolonise. Mosaic burning breaks up the fuel load
and can help to slow wildfires. In addition to unburnt patches, a mosaic of vegetation at different levels of post fire regeneration
will provide a variety of habitats for a wide variety of fauna species.
Fire intensity will vary depending on burn frequency, fuel load, temperature, moisture content and season. From an ecological viewpoint,
variation in fire intensity is desirable. Cool fires remove less leaf litter and are less likely to result in erosion, however the
seeds of some plants need a hot fire to break their dormancy.
There are no hard and fast rules regarding the correct season for burning. Factors that need to be considered are:
- Breeding times for
birds and animals
- Insect dormancy
- Availability of seed