Archaeology in the Fort McMurray Fire

View from a burned aspen stand to the Gregoire River valley.

At the end of June we started work on planned fire salvage harvest blocks for Alberta-Pacific Forest Industries, southeast of Anzac Alberta. This was the southeastern end of this springs massive Fort McMurray forest fire. When fire kills or damages a stand, there’s a limited time-frame within which the wood can still be salvaged for lumber or pulp. Planning for salvage started before the fire was under control. Once it was safe to do layout work we had a narrow window to get in and complete our Historic Resource Impact Assessment of the salvage plan before harvest operations would start.
As the Forest Management Agreement holder for most of northeastern Alberta, Alberta-Pacific Forest Industries has a long-term right to harvest aspen and poplar for their pulp mill north of Athabasca. This long term land tenure comes with a lot of responsibilities. These include a responsibility to salvage as much timber as they can from wildfires, and a responsibility to complete historic resource impact assessments of their operations.
The Historic Resource Management Branch of Alberta Culture understands that fire salvage is not part of a forest company’s normal Annual Operating Plan. It’s often difficult to know the final block boundaries until harvest is complete because the timber has to be damaged by the fire, but not too burned. There is therefore some concession given for late-season or last-minute salvage plans, which can be deferred to post-harvest impact assessment the following season.
In this case, Al-Pac wanted to ensure due diligence by completing their HRIA’s prior to salvage, so we started our fieldwork immediately after the layout crews finished putting up their block boundary ribbon. Fire salvage can be both a challenge and an opportunity for historic resource management. In addition to the logistical challenges of the narrow timeframe and uncertainty, working in a fire stand increases some safety hazards. There is of course the risk of holdover fires or flareups. There’s also an increased risk of blowdown from snags (standing dead trees) with their roots burned out and hangers (fallen trees and limbs hung up on other trees). Foresters call these “widowmakers” for a reason. There is often increased bear activity as they take advantage of the fresh green growth, grubs, and in later summer berry production, made available by the fire.
Forest fires also increase the risk of impact to archaeological sites. Forest harvest operations are normally pretty low impact, as far as archaeology is concerned. Feller-bunchers and skidders have large tracks and wheels to keep their footprints light. Under normal conditions, harvest leaves some tracks and trails, but the thick moss and duff of the boreal forest protect buried archaeological sites from a lot of the potential disturbance. A hot ground fire burns off much of the moss and duff, leaving the shallowly buried artifacts typical of the boreal forest much more vulnerable to exposure and displacement.
This factor is also what makes some fires an opportunity for archaeology. One of the hardest parts of doing archaeology in the boreal forest is the fact that everything is covered by a mat of moss, with almost no surface exposure. The only way to find sites is to dig labour-intensive shovel tests, and these provide very limited windows into the buried past. In a hot fire, the moss has been burned off, and we can see a much larger window. In some cases, scatters of artifacts, in-situ (in place) where they were left thousands of years ago, are sitting on the surface.
That wasn’t the case this week. We found a couple of sites where the fire didn’t burn quite that hot, including a probable Besant point, but we had to dig for them, as usual.
I also found a renewed appreciation for the resiliency of the boreal forest, and how well it’s adapted to a frequent fire regime. It’s only been two months since the fires burned through the area, and most of the burn is covered in a lush green carpet of fresh growth. Plants like fireweed, sasparilla, wild rose, raspberry and bunchberry have sprouted from root systems protected from the fire. Aspen and poplar suckers with huge deep green leaves are already knee to hip high. Insects are present in abundance, birdsong can be heard, deer and moose sign shows they’ve returned, and we saw a black bear sow with two cubs.

By salvaging the burnt timber, Al-Pac will help to fast-track that cycle of renewal, and will leave other areas they’d planned to harvest to grow for another season or two. By having us complete our historic resource impact assessments before harvest, we’ve identified and protected two potentially significant archaeological sites in an area that’s still pretty poorly understood. These are some good examples of how the forest industry plays an important role in Alberta’s woodlands, helping to manage multiple values on the landscape, and balance their operations with ecological and cultural concerns.


The Archaeology of Wildfire

This is a guest post by Christina Poletto, a Master’s student with the Institute of Prairie Archaeology at the University of Alberta Department of Anthropology. She’s studying the palaeoenvironmental signature of wildfire, to look for signs of pre-historic controlled burning by indigenous societies in northeastern Alberta.

Fire is almost a constant in Alberta’s north, and its impact can be felt not only on the environment but on populations. In recent years’ fire has been seen in a negative light due to extreme fires that have impacted communities in northern Alberta. The 2016 fire in Fort McMurray has had a devastating impact on people in the area, displacing thousands and damaging houses and buildings. However, fires were not always this large and destructive.

Fire Map
Wildfires from 1930 to 2014. This map only presents 84 years of fires in the area, but it shows the frequency and scale of fires in the region. (Fire history from Canadian Forest Service. 2011. National Fire Database – Agency FireData. Natural Resources Canada, Canadian Forest Service, Northern Forestry Centre, Edmonton, Alberta.; map created by C. Poletto)

As part of the boreal forest’s natural cycles, fires allowed for a diverse mosaic of landscapes to be re-established and helped support animal communities in the area. These natural fire cycles also help to remove ‘dead’ organic materials like fallen trees and overgrown plants. If these materials are left to build up, they become another fuel source for fire and make fires more intense. This has led fire scientists to argue that the more the forest is regulated and the more fires are suppressed, the more intense and dangerous fires become. In the years before fire suppression, fires were a crucial and positive part of the success and diversity of the boreal forest.

Dense forest cover can be both fun and challenging when accessing sites. For fires though, this can mean a faster moving and more intense burn (image C. Poletto)

In addition to natural fires, northern Alberta First Nations groups had traditions of cultural burning. These fires were highly regulated; they were only started under specific circumstances and were dependent on factors like weather conditions and the amount of fire fuel in an area. Early spring was the preferred season because the ground was dry enough to burn but damp enough to prevent the fire from getting too large, whereas during the fall it was drier, making it more dangerous to begin burning. When all the conditions were right, fires would be used to create landscape features like hay meadows or to form and maintain trails, and to promote plant and animal communities re-entering into an area. Ethnographic studies like ones conducted by Henry T. Lewis and Theresa Ferguson with the Dene-Tha (Slavey) in northwestern Alberta documented the longstanding tradition of controlled burning. Elders commented that these practices would not only promote the movement of people but would encourage vegetative communities to thrive and entice animals to revisit areas. In the forest, ensuring the availability of food resources for the months ahead and for years to come was the primary goal of these activities, which is why such great care was taken with the burning process.

In an archaeological site with deep deposits, records of these traditions could be noted by multiple layers of charcoal related to occupation periods. However, in many parts of the boreal forest, the soil deposits are shallow and make it challenging to see these patterns. Instead, researchers can look at soils in lake basins to help recreate these parts of the record. With these ancient and modern records, we can understand how different plant species respond to different fire types, and model the regrowth and response of animal communities. Understanding how First Nations groups manipulated these environmental relationships enhances our understanding of past groups living in the boreal forest. IN addition to its archaeological value, this knowledge can be integrated into modern forest management practices. In some parts of Alberta, highly regimented cultural burning through collaborative efforts has been reintroduced as a way to help minimize fire risk and to promote a healthy, diverse boreal forest.

This map of the Clear Lake – Eaglesnest Lake area in the Birch Mountains shows how we can use current vegetation data to see how the boreal forest responds to fire. It also serves as a baseline for future research to attempt to interpret the boreal forest’s story of fire from lake records (created by C. Poletto).