Can Air Quality Management Drive Sustainable Fuels Management at the Temperate Wildland-Urban Interface?

Abstract

Sustainable fire management has eluded all industrial societies. Given the growing number and magnitude of wildfire events, prescribed fire is being increasingly promoted as the key to reducing wildfire risk. However, smoke from prescribed fires can adversely affect public health and breach air quality standards. Here we propose that air quality standards can lead to the development and adoption of sustainable fire management approaches that lower the risk of economically and ecologically damaging wildfires while improving air quality and reducing climate-forcing emissions. For example, green fire breaks at the wildland-urban interface (WUI) can resist the spread of wildfires into urban areas. These could be created through mechanical thinning of trees, and then maintained by targeted prescribed fire to create biodiverse and aesthetically pleasing landscapes. The harvested woody debris could be used for pellets and other forms of bioenergy in residential space heating and electricity generation. Collectively, such an approach would reduce the negative health impacts of smoke pollution from wildfires, prescribed fires, and combustion of wood for domestic heating. We illustrate such possibilities by comparing current and potential fire management approaches in the environmentally similar landscapes of Vancouver Island in British Columbia, Canada and the island state of Tasmania in Australia.

Keywords: air pollution; air quality regulation; fire management; fuels management; green fire breaks; mechanical thinning; prescribed fire; public health; smoke; wildfire.

Figure 1.

Geographic context of Vancouver Island, Canada (left), and Tasmania, Australia (right). The broad vegetation cover of these temperate forested islands is controlled by elevation (A,B) and precipitation gradients (C,D). A feature of these islands are the complex wildland–urban interfaces (E,F). The location of the capitals of British Columbia (Victoria) and Tasmania (Hobart), and the regional towns of Port Alberni (population 18,000) and Launceston (population 85,000), are also indicated (A,B). Note that the vegetation maps do not depict intermixes of Garry woodlands in coastal Douglas-fir or differentiate between dry and wet Eucalyptus forest.

Figure 2.

Trends in wildfire season length for Victoria, Vancouver Island (A) and Hobart, Tasmania (B) from 1986 to 2016. While there is considerable inter-annual variation in an ensemble metric of wildfire season length (expressed as a standardized anomaly, standard deviation from the 1979 to 2013 historic mean) based on previous work [7]. These data show a steady increase in response to climate change.

Figure 3.

Seasonal and diurnal patterns of fine particulate matter (PM_2.5) concentrations in Port Alberni, Vancouver Island (A) and Launceston, Tasmania (B), averaged from 2009–2016 measurements with beta attenuation monitors. During the winter months (October–March in British Columbia, April–September in Tasmania) residential wood burning is the primary source of PM_2.5, with morning and evening burning creating the characteristic hourglass figure [32] and dwarfing the effects of smoke from prescribed and wild fires. The corresponding mean monthly maximum and minimum air temperatures for these locations are indicated (C,D).

Figure 4.

The effects of smoke pollution on public heath can motivate fuels management, appropriate built environment, and community engagement to achieve sustainable coexistence with flammable landscapes. The status quo (left side) sharply contrasts a plausible fuels management scenario designed to drastically reduce smoke pollution (right side). Artwork credit to Jen Burgess.