fire – photo supplied
Recent fire activity below levels of the past 2,000 years
Source: Ecosphere
Summary: New research uses lake-sedimentary charcoal records and tree rings from eight forested landscapes to unlock regional trends in fire activity in boreal forests of Manitoba and Ontario over the past 2,500 years.
The boreal forest of North America developed after the last glaciation about 10,000 years ago. With climate change and the human occupation of the territory, a greater risk of fire is anticipated, which could compromise the expected benefits of the forest for future generations. Are these effects already observable? A group of Canadian and European researchers provided an answer to this question after analyzing fire records in Manitoba and Ontario covering the past 2500 years. Their study, published on June 15th 2018 in Ecosphere, shows that no such overarching stimulation of fire activity has taken place in this part of the boreal forest during the recent years.
Forest Fire in Northwestern Ontario (Natural Resources Canada)
In this study, the researchers have discovered that for the last century, rapid changes in the climate and denser human occupation of the territory have had the opposite effect in the study area. First, they observed a reduction in the amount of biomass burned during the course of the last 2,500 years. This decrease in fires was briefly interrupted in the middle of the 19th century, marked by a sharp increase in fire activity. The amount of biomass burned gradually decreased in the 1930s, and this decline has accentuated since then. The level of fire disturbance is now lower than the historical level, despite global warming. To arrive at these results, the researchers reconstructed the fire history by searching archives (1920-2010) and by analyzing tree rings (1690-2010) (dendrochronology) and lake sedimentary charcoal records for the last 2,500 years.
While this may be perceived as encouraging for human-wellbeing (e.g., infrastructure, allowable cuts) this situation may not be without ecological consequences. The aging of the forest landscape as a result of this decrease in disturbance can lead to a loss of biodiversity, especially in fire-adapted species, while contributing to the emergence of large fires in the coming decades if no action is taken to manage fuels.
Story Source:
Materials provided by Natural Resources Canada. Note: Content may be edited for style and length.
Contact authors
Martin Girardin
Research scientist, Canadian Forest Service
Phone : 418-648-5826 (work); 418-527-7081 (home)
Email : martin.girardin@canada.ca
Dr. Jacques Tardif
Professor (Biology), University of Winnipeg
Phone: 204 786-9475
Email : j.tardif@uwinnipeg.ca
Journal Reference:
