Wildfire Risk: Untangling what we can and cannot change

Bigger, hotter, faster: Today’s Wildfires  

Three main factors are thought to drive wildfire behavior: climate/weather, fuels, and topography. These come together to shape what fires look like. At the scale of a single fire event, for example, a dense stand of coniferous trees may be at higher risk of burning than a mixedwood stand, and both would be at higher risk of burning after a drought on a hot and windy day. At the scale of the entire fire season, more area will generally burn more intensely if you have more susceptible fuel, coupled with hotter and drier summers.  

When we talk about the fact that fire behavior is changing, we generally need to consider two of the three factors above (climate and fuel), as topography generally doesn’t change (at least over the time scales we are talking about). Fortunately, we can and do have an impact on the fuel load, through our forest and land management practices, and on climate, through our actions on climate change.

Climate Change

Climate change is the key driver increasing wildfire risk through its impact on the weather and therefore the fuel. Wildfire impacts will continue to grow if we fail to address climate change. While the impact that climate change has on weather depends on where in the world you are, higher temperatures, changing rainfall patterns, increased lightning activity, changing wind patterns, and reductions in snowpack have all contributed to more severe wildfire conditions in Alberta.  

Increased temperatures directly increase wildfire threat by creating drier, more fire prone environments. Higher temperatures also create longer and hotter summers, thus extending the fire season. Climate change can also lead to more frequent and severe droughts which reduce moisture in plants and soil, exacerbating the impacts of higher temperatures. In British Columbia, for example, human-induced climate change was linked to a far greater probability of high-fire weather and larger burned areas (4). In eastern Canada, climate change was found to double the likelihood of extreme fire weather conditions (5).

Forest management  

The majority of Alberta’s forests, outside of protected areas, are managed by forest management companies. These companies, and the industry as a whole, can therefore play a key role in managing the impacts of wildfires and mitigating the threats posed by wildfires to people and ecosystems alike. This can be accomplished first and foremost by adopting more climate-adaptive management practices and reducing carbon emissions to achieve true carbon neutrality (6). Wildfire threat can directly be addressed by planting a more diverse mix of species, including those with fire-resistant traits, tree thinning, removal of deadwood, and supporting the re-introduction of cultural burning practices led by Indigenous communities. Traditional forestry practices which are driven by the need to maximize timber yield do not support wildfire and climate mitigation. 

Suppression of Natural fire regimes 

As we already know, fires play a pivotal role in Alberta’s forest ecosystems and keeping fires out of these environments, as has been standard practice for several decades, not only negates the potentially positive impact that they can have but can also increase the risk of more catastrophic fires. Fire suppression can lead to an increase in the amount of fuel available for fires, either through the accumulation of dry fuel or the build-up of fire prone species, thus resulting in bigger, more intense fires (7). Allowing forests to burn also allows them to continually adapt to changing conditions as fires act as a natural selection agent, promoting individuals with characteristics better suited to hotter, more frequent fires. This does not mean that all fires should be left unchecked given the reality of people living in the wildland-urban interface, but if these communities are better protected, pre-emptively, then fewer resources will need to be channelled into putting out fires once they start.

Homogenization of forest landscapes 

Forestry does not necessarily emulate or mimic wildfires. The benefits of wildfires that we mentioned earlier are not replicated through forest management techniques. Certain forestry practices can actually increase the risk of more intense wildfires in Alberta’s forests by impacting both the fuel load and forest microclimates. Find a previous blog here, where we debunk many of the forestry myths related to wildfire risk in Alberta. 

Clearcutting 

Clearcutting forests is often touted as a method to replicate the impact that fires have on forests, but the two are not the same. Wildfires, generally, do not remove all the trees in a forest, and do not burn uniformly across the landscape. This creates small patches which promote biodiversity and increase the resilience of the landscape to future fires. Clearcutting also leaves a significant amount of debris (deadwood) which can dry out and become highly flammable, and can also change the microclimate of the forest, making it hotter, drier and more prone to fire.  

Monoculture plantations  

The impacts of clearcutting are exacerbated by the planting of coniferous monocultures in place of diverse forests and, in particular, less flammable deciduous species, such as aspen. These plantations are often planted more densely than they would naturally grow (to increase production), and generally have a uniform structure, meaning fires can burn more intensely and spread more quickly. Monocultures, which lack the genetic diversity of natural forests, can also be more vulnerable to pests and diseases which can lead to the trees dying and potentially posing more of a fire risk. Forest companies that harvest coniferous species also spray the area that has been clearcut with glyphosate to suppress regrowth of deciduous trees. This practice also increases fire risk both by reducing the presence of trees that are less flammable than conifers for most of the season, but also by producing very flammable fuel.