Will climate change drive 21st century burn rates in Canadian boreal forest outside of its natural variability: collating global climate model experiments with sedimentary charcoal data

Abstract

Abstract. Natural ecosystems have developed within ranges of conditions that can serve as references for setting conservation targets or assessing the current ecological integrity of managed ecosystems. Because of their climate determinism, forest fires are likely to have consequences that could exacerbate biophysical and socioeconomical vulnerabilities in the context of climate change. We evaluated future trends in fire activity under climate change in the eastern Canadian boreal forest and investigated whether these changes were included in the variability observed during the last 7000 years from sedimentary charcoal records from three lakes. Prediction of future annual area burned was made using simulated Monthly Drought Code data collected from an ensemble of 19 global climate model experiments. The increase in burn rate that is predicted for the end of the 21st century (0.45% year À1 with 95% confidence interval (0.32, 0.59) falls well within the long-term past variability (0.37 to 0.90% year À1 ) . Although our results suggest that the predicted change in burn rates per se will not move this ecosystem to new conditions, the effects of increasing fire incidence cumulated with current rates of clear-cutting or other low-retention types of harvesting, which still prevail in this region, remain preoccupying.

Wildfires in boreal ecosystems: past, present and some emerging trends

“…Nonetheless, even though fire is a long-term intrinsic property of the boreal forest (Bremond et al 2010;Carcaillet et al 2010;Higuera et al 2010), its occurrence is increasingly linked with human activities (Marlon et al 2008;Bradshaw et al 2010;Niklasson et al 2010;Wang and Anderson 2010). This influence has up until now been direct, via ignition, but the indirect influence through human-induced climate change is becoming worrisome (Flannigan et al 2009;Bergeron et al 2010;Metsaranta 2010). Furthermore, the cumulative impacts of fire and clear-cutting or other low-retention types of harvesting are becoming increasingly preoccupying when faced with the potential for these forests to exceed ecological thresholds (Cyr et al 2009;Bergeron et al 2010).…”

“…This influence has up until now been direct, via ignition, but the indirect influence through human-induced climate change is becoming worrisome (Flannigan et al 2009;Bergeron et al 2010;Metsaranta 2010). Furthermore, the cumulative impacts of fire and clear-cutting or other low-retention types of harvesting are becoming increasingly preoccupying when faced with the potential for these forests to exceed ecological thresholds (Cyr et al 2009;Bergeron et al 2010). The 'Wildfires in Boreal Ecosystems' conference and this special issue illustrate how effective collaborations can be developed amongst researchers of Eurasia and North America sharing similar interests.…”

“…This approach could offer a robust forecast for the future uncertainty that could be directly implemented in some aspects of sustainable forest management. The work by Bergeron et al (2010), by using multiple climate models, is an initial step in this direction.…”

“…Each model approach has strengths and weaknesses, but all are affected by the same uncertainties associated with future atmospheric CO 2 emissions, population growth, land-use changes, etc. Bergeron et al (2010) use the hybrid approach on an ensemble mean of 19 global climate model experiments to predict future fire activity in eastern boreal Canada. Using a synthesis of charcoal sedimentary data from three kettle lakes in their targeted region, the authors further assess the risk of seeing future fire activity exceed the historical range of variability.…”

Influence of Fuel Load Dynamics on Carbon Emission by Wildfires in the Clay Belt Boreal Landscape

“…Managers should consider practices that favor mature forests for harvesting but also increase potential forest vulnerability to higher carbon emission and decrease long-term carbon storage [36]. In fact, although the climatic conditions expected by the end of the 21st century may induce an increase in fire activity in the Clay Belt boreal region (e.g., [22][23][24]), expansion of old-growth BS forests in the landscape is projected [60]. If fire activity over the next three to four decades remains similar to current levels, an increase in the proportion of forests characterized by high soil moisture conditions will occur [60].…”