Canterbury wildfire reinforces international findi
Canterbury wildfire reinforces international findings
The degree of damage sustained by Canterbury homes during recent wildfires is not just a question of luck, says Forest Research fire scientist Grant Pearce.
Following investigations of the fire at West Melton in which one house was destroyed while several nearby properties escaped damage, Pearce says the results clearly reinforce the need for greater fire awareness by property owners.
Studies of house losses following major wildfire events in the United States and Australia, including last January’s Canberra fires where more than 400 homes were destroyed, have found that factors contributing to house loss include: building design; construction materials; and presence of vegetation or other flammable materials next to the house.
Pearce points out that most of these factors are within the property owner’s control. “Provision of defensible space refers to the creation of a buffer zone around a home or property in which flammable fuels have been removed or reduced. Overseas experience has shown that a zone of a least 30 m is best.”
Pearce says that a comparison of properties threatened by the West Melton wildfire clearly reinforces these contributing factors. “The house destroyed by the fire had plastic roofing materials over the conservatory area. It also had firewood and straw bales stored next to the house. These factors contributed to its ignition and subsequent loss. In contrast, a neighbouring house was totally unscathed because it was built almost entirely of metal materials and was surrounded by a small but frequently watered lawn and well maintained gardens.”
The presence of residents and firefighters to defend properties was another key factor in reducing the number of properties damaged. “In several cases, the actions of residents (as well as fire services) in wetting down vegetation and extinguishing low intensity fires using garden hoses and irrigation systems was instrumental in saving many properties,” says Pearce.
As the line between forests, farmland and cities becomes increasingly blurred, Pearce stresses the need for comprehensive fire risk management strategies involving all parties. “Since 1988/89 there has been an annual average of about 2000 wildfires that burn around 7000 ha of rural lands (including forests). The number of vegetation fires reported is increasing at a rate of approximately 300 fires per year, with a total of over 4500 fires in 2002/03.”
Forest Research offers the only rural fire research programme in New Zealand.