Planned burning can only occur when the conditions are right and it is safe to ignite and manage a burn. The right conditions usually arise in Autumn, which is when we carry out most of its planned burns. This is because the weather is more stable in Autumn and we get ideal conditions —sunny days, light winds, cool nights and overnight dews — for planned burning.
Combined with the right fuel moisture – which is in the 12–16% range – these short windows of opportunity allow us to safely ignite and manage the burns.
However, some types of vegetation require different conditions for a burn to go ahead. We can ignite some types of vegetation at any time, even in winter, but some types of vegetation in certain areas have a very small window of opportunity when conditions are right – this is often only a few days each Autumn.
For example, fuel conditions quickly go from too dry to too wet in the Otway forests, in the Dandenong Ranges and in Wombat Forest near Daylesford.
We call periods of the year where the weather and vegetation conditions are right for planned burning ‘peak burn windows’. Some windows are only one or two days a year, some are seven days in a season, while some locations have no major timing constraints.
Maximising the outcomes of each burn is our top priority. That means prioritising burns that will result in the greatest reduction of risk to life and property from a major bushfire, and also prioritising burns that are important for other reasons such as burns that reduce local risk or maintain or improve forest and ecosystem health.
Our staff travel widely across the state during a peak burn window to maximise opportunities to carry out fuel management. When several regions have peak burn windows at the same time, our staff and equipment can become stretched to the maximum, and we have to decide where to allocate resources. We choose areas of highest priority, where will achieve the greatest risk reduction under the right conditions.
We use computer simulations to identify which of the burns planned across Victoria each year will result in the biggest risk reduction. However, the need to reconcile risk-reduction priorities with the other factors — weather conditions, vegetation type, the size of peak burn windows, local priorities and organising and moving resources — calls for ever-increasingly sophisticated modelling and decision support.
Accordingly, we have developed and last year implemented for the first time our new planned burn optimisation tool. This decision support tool enables us to consider all factors simultaneously to determine which burns we should do next —burns that offer high risk-reduction and address local priorities but only have very narrow window of opportunity. The tool was co-created by our fuel management experts and risk analysts to create an efficient way of analysing and displaying data to better support decision makers.
Not only does the tool improve our decision making about where to conduct planned burns and when, it also provides the evidence we can use to explain those decisions to staff and to communities who may be directly impacted by planned burns. It builds trust with communities, which is the foundation of our community-based bushfire management approach.
Last year, our staff in the regions used the tool for the first time to prioritise their program. It supported planning and resource allocation around the state.
The Planned Burn Optimisation Tool:
- translates the three-year fire operations plan into a 12-month planned burning program
- gives each planned burn a ‘Victorian burn effectiveness rating’, showing how much it would reduce the state’s residual risk
- gives each burn a regional rating, which takes account of the amount of local risk it reduces, its cultural and ecological priority, and its alignment to the regional strategic bushfire management plan
- determines which burns have very high importance, which have high importance, and which have standard delivery importance
- identifies the extent of the burn windows required for each high importance burn.
This information enables us to be well prepared to conduct a planned burn should the right conditions present a window of opportunity.
Page last updated: 17/10/18