By Guest Blogger Laura Nguyen
If you were taking a leisurely hike in High Park, walking your dog, or eating out at Grenadier Restaurant on Friday, April 15th around 2-5 PM you may have witnessed smoke rising, fires spreading, or fire experts watering the freshly torched ground. The City of Toronto’s Urban Forestry staff and burn experts worked together to set this low-burning fire as part of the City’s long-term Woodland and Savannah Management plan to restore and protect declining savannah habitats in High Park. This is the 13th time that intentionally set fires called “prescribed burns” graced over specific areas of the park since the initiative began in 2000. Prescribed burns are like prescribed medicine where foresters administer fire to boost the health of savannah ecosystems the way doctors provide treatments for illness. Every year different sections are burned and this year the sites were the savannah by the Bloor Street West entrance and behind the Grenadier Restaurant and baseball diamond which are labelled as the red portions on this map:
Black oak savannahs are characterized by tall grasses, wildflowers, an open canopy, sparse trees, sandy soils and frequent fires. The Area of Natural and Scientific Interest (ANSI) designated savannahs cover 1/3 of High Park and are home to 26 nationally rare plants such as the showy tick trefoil, wild lupine, butterfly milkweed, and the cup-plant. These plants are threatened by degradation, fragmentation, invasive species, and lack of fires that would regularly stimulate optimal growth conditions. Naturally, fires would be promoted by dry soil conditions under the hot sun and historically Indigenous groups maintained fires when hunting and clearing riparian areas. European settlers suppressed the fires from the 1870s to 2000 due to safety concerns as houses were built in closer proximity to the park, but the city took immediate action once they recognized the detrimental effects that this has on savannahs.
Controlled fires that are low to the ground help clear out competitive invasive species like European buckthorn, Norway maple, Himalayan balsam, and garlic mustard that reduce the diversity of native plants. Native species have adapted to fires which gives them an advantage over many invasive plants that cannot survive the extreme heat. Black oak trees have thick bark that protects them against low intensity fires and savannah grasses have root systems extending 4-5 meters below ground, unlike invasive plants which have short roots. The photo below illustrates the shallow root system of an invasive grass (the first one from the left) compared to longer native grass roots following it. In addition, the heat from fires creates ideal conditions for seed germination to ensure young oaks are replacing the older trees.
Prescribed burns are an important part of sustaining the black oak savannahs in High Park, but this strategy is only a part of the plan. The City of Toronto’s High Park Restoration crew monitors the post-fire period along with planting native species and controlling invasives throughout the rest of the year. High Park savannahs are managed in these ways, but it is our responsibility as visitors to the park to conserve these areas by walking on designated paths to prevent trampling, respecting wildlife, and disposing of litter in appropriate bins. If you can think of other ways to restore and protect the black oak savannahs, share them with your friends and family! Now that the fire has been put out, I encourage you to go out yourself and enjoy all the wonders of the savannah!
Dinh, Theresa, Hewitt, Nina and Drezner, Dawn Taly. “Fire History Reconstruction in the Black Oak (Quercus velutina) Savanna of High Park, Toronto”. Natural Areas Journal 35.3 (2015): 468. Web. 30 Nov. 2015
Rare Plants of the High Park Black Oak Savannah: A Volunteer Stewardship Program Guidebook. Toronto: High Park Initiatives, 2008. 32-37. Print.
Toronto Parks, Forestry and Recreation. High Park Oak Savannah and Woodlands Restoration. Toronto: Toronto Parks, Forestry and Recreation, 2016. Print.