- Title:
-
Fuel Reducing a Stand of Eucalypt Regrowth in East Gippsland: A case study
- Date:
- April 1992
- Organisations
- DSE
- Authors:
- Andrew J. Buckley
- Location:
- Victoria, VIC, Australia
Overview
Planning and operational factors that should or must be considered when implementing prescriptions for fuel reducing stands of eucalypt regrowth are identified and discussed, based on a case study conducted on 3 April 1990 in a 16 year-old stand with a bracken understorey at Buchan South, East Gippsland, Victoria.
Fuel and stand characteristics were measured prior to the burn. Spot fires were ignited in a grid pattern throughout the 15 ha study site and the behaviour of one of the fires was measured. Mild weather conditions with wind speeds generally less than 5 km/h and forest fire danger indices less than 5 prevailed during the burn. Fire behaviour varied considerably, with about two-thirds of the area being burnt by fires with rates of spread of between 10 and 50 m/h and fireline intensities of between 50 and 240 kW/m. Higher intensity fire behaviour occurred in dense bracken fuels with a maximum rate of spread of 94 m/h and fireline intensity of 460 kW/m.
An analysis of the scorch and fire behaviour data showed that rates of spread of greater than about 50 m/h or fireline intensity of greater than about 240 kW/m caused excessive damage to the upper crowns of trees in this stand of dominant height 14m. Stem damage, caused mostly by burning logging debris, occurred to 9 percent of stems.
The planning and operational actions that are recommended to be implemented by staff to achieve fuel reduction burning objectives without causing unacceptable damage include:-
- Prepare adequate control lines and fall stags on boundaries.
- Measure stand height.
- Measure litter and shrub fuel loads and assess shrub fuel distribution.
- Construct rough walking tracks to give lighting crews easier and safer access within the burning unit.
- Monitor broadscale weather patterns.
- Monitor and measure local weather.
- Monitor and measure fuel moisture content.
- Predict rate of spread using the McArthur forest fire danger meter (in the absence of other, fuel type specific, fire behaviour guides for fuel reduction burning).
- Ignite a test fire on level ground and, after at least 20 minutes, measure the rate of spread.
- Use the test fire rate of spread and the slope on the area to be burnt to plan the spacing of ignitions.
- Ignite the burn boundaries with spot fires.
- Ignite the stand with a planned, widely spaced grid system of spot fires.
- Ignite spot fires to burn up-slope only on slopes less than about 10°.
- Plan for spot fires to join in the late afternoon or early evening.
- Conduct a second stage burn if coverage from the first stage is less than about 50 percent.
