Effects of wildfire on biomass combustion in boreal peatlands and forests

Regions: Dehcho Region, South Slave Region

Tags: climatology, biology, vegetation, forestry, peatlands, wildfire

Principal Investigator: Turetsky, Merritt R. (4)
Licence Number: 14958
Organization: University of Guelph
Licenced Year(s): 2011
Issued: Aug 12, 2011
Project Team: Eric Kasischke (Investigator, Professor of Geography, Ecologist, University of Maryland), Courtney Miller (Technician, University of Guelph), Dan Greenacre (Technician, University of Guelph), Brian Benscoter (Investigator, Assistant Professor of Ecology, Florida Atlantic University)

Objective(s): To quantify the amount of fuel combustion and carbon losses during wildfires in boreal conifer forests and peatlands; and to quantify climatic and weather controls on the severity of biomass burning.

Project Description: The objective is to quantify the amount of fuel combustion and carbon losses during wildfires in boreal conifer forests and peatlands. These data will allow us to quantify climatic and weather controls on the severity of biomass burning.

Boreal forests and peatlands store a large amount of carbon in vegetation and soils. Climate change is predicted to increase summer drought, which could make deeper, carbon-rich peat more vulnerable to burning. Peat fires currently are problematic for fire management because they require increased financial and suppression resource commitments. Extinguishing smouldering peat is time consuming, labour intensive, and serves as a serious draw-down on firefighting resources for suppressing new fires. We currently do not have the necessary understanding or tools to predict the occurrence or extent of smouldering combustion or peat fires. This research will lead to the development of tools to guide fire management planning under peat fire conditions. By providing information on the most important natural disturbance affecting boreal peatlands and forests, this research also will benefit the environmental and socioeconomic values provided by boreal peat resources.

Approximately $500 million (and up to $1 billion) is spent on fire management activities in Canada each year. Uncontrolled wildfires threaten the safety of nearby communities, although fire emissions can be far-reaching due to long-range transport. Area burned each year in Canada is expected to rise substantially with climate change. This research will provide information necessary for detecting and predicting deep burning fires. This will allow managers time to plan suppression strategies to mitigate or prevent the occurrence of large smoldering fires that can lead to evacuation of northern settlements (due to health and safety), extended and expensive commitment of firefighting resources, and loss of large carbon stores. Tools and strategies include planning aerial detection routes, use of peatlands as natural fire breaks, scheduling of alert levels, pre-positioning of suppression resources in most critical areas, and increasing of resource levels at critical time periods.

Sampling in burned sites:
The research team has used historical fire polygons to identify sites south of Yellowknife that have burned near roads since 2004. At each site listed in the permit, multiple 40 meter by 40 meter plots will be identified in a homogenous patch of conifer forest or peatland. The range of habitats and fire severity conditions present within each fire scar will be sampled. Sampling will be along roads as much as possible, or will access more remote sites by hiking a maximum of 4 km from a road. In each plot, observations necessary will be collected to calculate the Composite Burn Index (CBI). The CBI is a semi-quantitative index of fire severity, and involves observations of biomass remaining after fire with no destructive sampling.

Sampling in mature stands:
At each fire scar listed in this permit, the nearest mature forest and peatland will be identified for characterizing pre-fire vegetation and soil conditions. These unburned data will important for assessing the impacts of burning on biomass. Forty meter by 40 meter plots will be established in unburned patches of forest and peatland near each fire scar. At each plot, the team will nondestructively measure the depth of the organic soil layer above the mineral soil interface (using the same methods identified above). For trees within each plot, the researchers will nondestructively measure tree density and diameter. They will also measure the depth of adventitious roots beneath the surface of the organic layer in relation to total organic soil thickness. At 10 randomly selected locations in each plot, organic soil horizons will be harvested using the metal corer or Macauley corer as described above. These samples also will be transported to the University of Guelph for future analyses.

Annual reports and copies of all theses and manuscripts will be sent to communities near the field sites. The research team would welcome the opportunity to provide community talks on climate change and wildfire in Canada, and will contact local communities to inquire about interest and timing.

The fieldwork for this study will be conducted from August 15, 2011 to August 30, 2011.