Applying landscape principles to fire hazard reduction

Abstract

Fire spreads in a specifically spatial manner, which suggests the applicability of percolation models to the risk reduction problem. It is shown that under fairly general conditions a threshold exists below which a landscape becomes essentially fireproof. Arranging treated acres into a grid, analogous to bulkheads on a ship, drastically reduces the acreage that must be treated to achieve a fireproof condition. Such compartmentation of the landscape yields a much higher leverage (ratio of acres saved to acres treated). Certain landscape features create updrafts that spread fire particularly far. Treating fuels in such areas yields high leverage. Fire shadow effects were replicated by the simulation and showed a possible mechanism for amplifying treatment effectiveness. Either fuel reduction programs or commercial forestry can be used to achieve hazard reduction without excessive costs if spatial aspects of fire spread are taken into account. #

Is there an inherent conflict in managing fire for people and conservation?

“…Increasing the area treated through planned burning and generating a measurable reduction in wildfire extent has been previously referred to as leverage (Loehle 2004). Leverage varies according to the annual extent of wildfire, extent of fuel treatment and the rate at which fuel loads recover (Price 2012).…”

“…Leverage varies according to the annual extent of wildfire, extent of fuel treatment and the rate at which fuel loads recover (Price 2012). Leverage has been analysed on individual burns (Loehle 2004) and across landscapes (Boer et al 2009;Price et al 2012;Price et al 2015a). In a bioregional analysis of south-eastern Australia, Price et al (2015b) found no evidence of leverage within the study area's bioregion for the period 1970-2010.…”

The influence of prescribed fire on the extent of wildfire in savanna landscapes of western Arnhem Land, Australia

“…Loehle (2004) introduced the term Leverage to be the reduction in area of subsequent fire resulting from the treatment of one unit area. It can be derived empirically as the absolute value of the slope of the relationship between annual area treated (x) and subsequent annual area of wildfire (y).…”

Fire severity and ecosystem resilience – lessons from the Wombat Fire Effects Study (1984-2003)

“…'Leverage' has become a popular way of quantifying the value of prescribed burning in reducing the extent of wildfires (Loehle 2004;Boer et al 2009). However, this simple metric does not adequately compare a hectare burnt by wildfire with a hectare burnt by prescribed burning because the severity of the fires and the resilience of the areas burnt are not considered.…”

“…However, this simple metric does not adequately compare a hectare burnt by wildfire with a hectare burnt by prescribed burning because the severity of the fires and the resilience of the areas burnt are not considered. Loehle (2004) found that strategically located hazard reduced areas could result in protection of a much larger area of the landscape. He suggested that by treating about 30% of the landscape, a wildfire would be unable to spread beyond a small area and hence the area was 'firesafe'.…”