The increase in the frequency of forest fires in Canada’s boreal forest could permanently transform one of the last intact ecosystems on the planet, according to a study by the University of Alberta and Natural Resources Canada.
The study examines the impact on the boreal forest of the increased frequency of forest fires due to climate change.
To do this, Ellen Whitman, a forest ecologist at the University of Alberta and Natural Resources Canada, and her colleagues compared areas of forests with similar climate and soil conditions. Part of these forest areas had been burned no more than 17 years ago, while the other part had been burned at least 30 years previously.
The study reveals striking differences between the two types of scopes, according to the study co-author.
We are pretty sure the effects will persist.
The areas where the intervals between the fires were shorter show much less trees. The majority of them are aspen, instead of the usual conifers.
Vegetation under trees such as shrubs and grass, which normally covers the soil, is less abundant and diverse. The areas of bare mineral soil where organic matter has been burnt are also larger and more widespread.
We are in a landscape made up of small stunted trees , says Ellen Whitman.
There is a lichen crust or some sparse herbs. It’s almost like walking on the edge of a meadow and crossing a forest edge , adds the scientist.
In comparison, areas with longer forest fire intervals are much more densely colonized by vegetation.
There are many conifers and they are closer to each other. There is moss on the floor, flowers and shrubs. These areas look like young forests , she explains.
Increasingly frequent fires
Several tree species need forest fires to reproduce, so flames play an important role in the evolution of the boreal forest.
Forest fires usually occur at least every 30 years or more. Lack of fuel in recently burned areas helps control this frequency.
Climate change is a game-changer, however.
We have warmer and windier days: the trigger for large forest fires. The years when there are extreme fire risks are becoming more frequent, and these conditions overcome the resistance of recently burned areas , says Ellen Whitman.
Nor do parklands have the opportunity to develop in the boreal forest. Studies show that the regeneration of a forest largely depends on the period following the forest fire.
The state of the forest immediately after a fire is a big indicator of what it will look like in the future , says the researcher.
Ellen Whitman insisted, however, that the areas of forest at short intervals are still small and that most areas of the boreal forest that have been recently burned are growing normally. Wetlands are also less affected by forest fires with short intervals than drier regions.
Consequences for the ecosystem
The researcher ultimately says that, although the forest industry should not be affected any time soon, forest-dependent animals such as caribou and songbirds will be affected by the increase in forest fires.
With a longer fire season, larger fires and more of the landscape burned each year, the likelihood of encountering a recently burned area increases. We are experiencing a reduction in the frequency of fires in the boreal forest , concludes Ellen Whitman.