People and Bushfires Geoff Cary

1. People and Bushfires Geoff Cary SRES 1001/6101

2. Integrated Model of Bushfire Risk D = I . S . E . G . H D = probability of an adverse outcome I = probability of ignition in the landscape S = probability of fire reaching the urban interface E = probability of encroachment into the built environment G = probability of fire propagation within the built environment H = probability of fire propagation within buildings Bradstock & Gill (2001) J. Med. Ecol. 2: 179-95

3. Bushfire arson The Australian population has grown by 50 per cent over the last 30 years, recoded arsons have increased by 2000 (two thousand percent) per cent. Paul Wilson (2003) Fire policy making :a social scientists perspective in Australia Burning: Fire Ecology, Policy and Management Issues, CSIRO Publishing.

4. Prescribed burning Cary and Bradstock (2003) argue that in the absence of knowledge on the relationship between: • percent of a landscape burnt by prescribed fire annually, and • probability of unplanned high intensity fire at a point Managers can only speculate on the effectiveness of prescribed burning Cary & Bradstock (2003) Sensitivity of fire regimes to management in Australia Burning: Fire Ecology, Policy and Management Issues, CSIRO Publishing.

5. Integrated Model of Risk Management

6. Prescribed burning The primary problem in bushfire management in Australian native forests today is the failure to undertake prescribed burning programs for fuel reduction (and for other purposes), or at least to ensure that such programs are adequate and effective. IFA submission to COAG Inquiry on Bushfire Mitigation and Management

7. Interface management Ventura County Dodged a Bullet (LA Times, 2 November, 2003) “Flames tore through brush faster than Ventura County Fire Chief Bob Roper had ever seen in his 27-year career. And in the first hours, the wildfires were racing toward thousands of homes in Simi Valley, Moorpark, Fillmore and Piru.Yet, Ventura County was spared widespread destruction in the fires that struck Southern California last week. Of the 3,000 homes and businesses destroyed, just 38 were in Ventura County, even though more than 172,000 acres burned.The county's tough brush clearance law was a critical factor, said Bill Peters, a spokesman for the California Department of Forestry.Ventura County requires homeowners to provide a 100-foot clearance around woodland homes each spring. Other counties adhere to the state's 30-foot standard, Peters said. That extra 70 feet "makes a huge difference," he said.”

8. Importance of gardens Assuming a bulk density of 60 kg.m-3 ….. • 20 mm deep layer of eucalypt litter in a long unburnt forest provides 1.2 kg.m-2 of dry fuel and a fireline intensity (FFDI 50) of around 3,500 kw.m-1. • 40 mm deep layer of eucalypt mulch in a residential garden provides 2.4 kg.m-2 of dry fuel and maybe a fireline intensity (FFDI 50) of greater than 15,000 kw.m-1.

9. Building design Windows are the most vulnerable features of a building exposed to bushfire attack. …. Wire mesh reduces, to some extent, the levels of radiant heat impacting on the glazing and, if the glass racks and falls away, it can help prevent wind-borne burning debris from entering the building.” Leonard (2003) in Australia Burning: Fire Ecology, Policy and Management Issues, CSIRO Publishing.

10. Integrated Model of Bushfire Risk D = I . S . E . G . H D = probability of an adverse outcome I = probability of ignition in the landscape S = probability of fire reaching the urban interface E = probability of encroachment into the built environment G = probability of fire propagation within the built environment H = probability of fire propagation within buildings Bradstock & Gill (2001) J. Med. Ecol. 2: 179-95