Putting fire to work for conservation

By Jeralyn Bohms

This spring, Parks Canada staff conducted a prescribed fire on a small area of the meadow at Fort St. Joseph National Historic Site. While the flames may have been the most exciting part of the multi-year project, work remains to evaluate the fire’s impact on the site’s cultural and natural resources.

A meadow habitat restoration project at Fort St. Joseph has been ongoing since 2021. The goal is to protect the site’s cultural and natural legacy by providing critical meadow habitat for monarchs, while also preserving the archaeological ruins around Fort St. Joseph. Monarch butterflies are now listed as an endangered species in Canada, and Parks Canada continues to be committed to their protection.

Over the past three years, much work went into preparing for such a small prescribed fire. The goal is to test the effectiveness of prescribed fire in controlling the spread of trees into the meadow that surrounds the fort ruins. In 2021, archaeologists surveyed the chosen plot to gather data about the soil profile and the location and depth of any archaeological resources. Some “test” artifacts were left in specific locations in the plot to be relocated and analyzed after the fire. An initial assessment of milkweed and blooming plant species in the proposed burn area was also conducted over the course of an entire summer.

While the prescribed fire was initially planned for the spring of 2023, the weather did not cooperate, so it was delayed until this spring. A weather station was set up so the Parks Canada fire team from Pukaskwa National Park could monitor local conditions, and in early May, everything was ready. Members of the fire crew used drip torches to ignite the fire, while others had water packs to wet down the edges of the plot, ensuring that the fire remained within its designated perimeter. Numerous hose lines and a water truck were also on site to ensure the fire did not travel further than desired. The area was ignited in bands, starting in one corner, and working into the wind toward the opposite corner. As the drip torches lit the grass, the wind blew the fire towards the previously burned band, where it died when there was no vegetation or fuel left to burn. The process went very quickly thanks to good conditions and the skill of the team. The prescribed fire was completed in under 30 minutes.

Throughout the summer of 2024, the regrowth of vegetation in the plot will be monitored. Every month the number and species of blooming plants will be recorded. The findings will be compared to data from before the fire to see how the burn impacted the presence and growth of various plant species. Of particular interest is the presence of common milkweed (the host plant for monarch caterpillars) and the regeneration of tree saplings. In the fall, the archaeology team will return to recover the “test” artifacts and document the soil profile again. This assessment will evaluate the impact of controlled fire on buried archaeological resources in the meadow.

Once all the data is collected, Parks Canada will use it to assess the success of the project and determine if more prescribed fires will take place.

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