International Journal of Wildland Fire
Volume 24
Number 5 2015
Humans have an important effect on fire size, but this has so far not been well quantified at a global scale. Here we describe a linear negative relationship between mean fire size and population density over the globe. We use this information to improve the global fire model SPITFIRE–JSBACH.
We developed a statistical model to predict whether random points on the urban interface were burnt by a sample of 677 past wildfires. The model had 98% accuracy and shows promise for predicting and mapping wildfire risk. Fire weather, the extent of forest, distance and time-since-fire were important predictors.
Managed fires using spot ignition in spinifex open woodland of northern Australia can produce a more patchily burnt landscape, with less canopy severity than wildfires. The high severity of wildfires appears strongly influenced by fire front length, irrespective of fire season.
We showed that shrubland fuel levels in semiarid Australia gradually accumulated for many decades following burning due to increases in shrub size and density, and buildup of dead plant material. This suggests that fire hazard will also increase over such time frames and that prescribed burning may help reduce this threat.
Interactions of shrub fires were studied by physics-based modelling. Peak mass-loss rate and vertical fire spread rate were found to be larger for cases with a smaller separation distance between the shrubs. Generation of strong vorticity by higher gravitational torque appeared to be the cause of enhanced burning in the three-shrub arrangement.
We present a model of radiant heat incident on homes affected by wildfire. The model uses spatial information describing topography and arrangement of vegetation in the near vicinity. The attenuating influence of fuels that lie between the flame and the building are included in the calculation and their significance evaluated.
Spatial relationships between fire density and biophysical and human-related factors were found in in a south-eastern France study, pointing to wildland–urban interface as the principal driver of fire density; but at a smaller scale, some of these factors spatially varied. A better understanding of their influence on fire density will help to improve fire prevention at a fine scale.
The potential of spatial fuel maps to improve estimation of wildland fire carbon emissions in Canada’s National Forest Carbon Monitoring, Accounting and Reporting System was evaluated. The use of spatial fuel maps was found to increase the precision of estimated total carbon emissions for select wildfires in western Canada.
We reconstructed fire regime characteristics of a mixed conifer forest landscape in northern Arizona and analysed composite fire intervals, point fire intervals, natural fire rotation, landscape characteristics and forest age structure. Results showed that the historical fire regime on this landscape was one of high-frequency, low-severity fires.
We investigated avian responses to patchy, low-severity prescribed fire at two spatial scales. Prescribed fire increased bird diversity at finer spatial scales and allowed persistence of species detected in pre-fire surveys. We recommend formal incorporation of patchiness into prescribed burning for ecologically sensitive fire management.
The paper presents analysis of the soil nematode communities as indicators of soil conditions 8 years after a wildfire in the spruce forest ecosystem. Results indicate that the soil ecosystem had recovered by this time.
We compared the effect of fire extent, fire frequency, season and spatial heterogeneity (patchiness) of the burnt area on mammal declines in Kakadu National Park over a recent decadal period. Fire extent was the most important aspect of fire regimes associated with declines. Small mammals appear most affected by extensive (at scales larger than the home ranges of small mammals) and less patchy fires.
Fires in radiological contaminated areas may expose firefighters to airborne radioactive material. Modelling fuel conditions and smoke dispersion for a range of case studies showed regulatory dose limits were not exceeded in most cases. Consideration of plume rise further reduced the predicted dose. Our approach can be applied to a range of burn scenarios.