Source: City of Toronto Precribed Burn Notices April 2008/2019
A prescribed burn is a deliberately set and carefully controlled low fire that consumes dried leaves, small twigs and grass stems, but does not harm larger trees. Prescribed burns are part of Urban Forestry’s long-term management plan to restore and protect Toronto’s rare black oak woodlands and savannahs.
The Role of Fire
Since 2000 City of Toronto Urban Forestry has been using fire as a management tool to help restore and expand High Park native plant communities including the globally rare Black Oak savannah habitat. Currently, 28 ha of oak savannah are burned on a rotating cycle. (See Summary of Burn Cycle by Management Unit.)
Prior to European settlement, fire played a pivotal role in maintaining the prairies, savannahs and oak forests that once extended across southern Ontario. This included deliberate burns set by Indigenous peoples as well as naturally occurring wildfires. (See Indigenous History of Today's High Park.)
Fire is an important factor in a healthy oak savannah as it helps to encourage and invigorate native species that have evolved to persist in fire controlled systems. Indigenous peoples used fire to maintain lush grasslands that attracted deer and other game for hunting.
Prairie plants including black oaks respond to modified site conditions following the burn, and grow more vigorously than they would have in the absence of the fire. Fire also works in reducing competition from some invading exotic species that are not adapted to a fire controlled ecosystem.
Successes of the High Park Burn Program
The natural fire cycle had been suppressed in High Park for over 100 years, and although regular fires have only been occurring since 2000, large improvements are already being observed in the distribution and health of native plant species in the park.
The initial goals for the prescribed burn program established in the management plan focused on enhancing the growth of native species while controlling exotic plant species. Special attention was also focused on targeting small rare plant communities existing in High Park in the hope of encouraging their natural expansion. Annual monitoring for the past several years has shown that many areas in High Park are exhibiting large increases in native plant community patches, as well as a significant decline in some of the exotic species controlled by burning, such as garlic mustard.
High Park is home to many rare and important species that are thriving from prescribed burning. Species in the drier savannah areas are showing large success in expansion such as dryland blueberry, Indian grass, big bluestem, woodland sunflower, sky-blue aster, and a variety of goldenrods and sedges. Wild lupine populations have exhibited an immediate response, with increases in patch size as well as seed production.
In the beginning stages of the prescribed burn program, frequent burns were necessary to reverse the effects of the approximately 100 years of suppressed fire cycles. More frequent burning was required to set-back exotic invasive plants such as buckthorn and honeysuckle, allowing more light to penetrate into the savannah habitats.
Restoration of natural areas is an adaptive process. As the successes of the High Park prescribed burn program continue, the frequency and interval between burns are reevaluated and adjusted accordingly.
Prescribed burn management, in combination with native species planting and invasive species removal, will continue to be a valuable tool used in these rare habitats to ensure their longevity and proliferation.
Media coverage of past burns:
- NOW Magazine article with photos, April 16, 2015
- CTV News article, April 2015
- The Guardian photo highlight of the day, April 16, 2015
- High Park Prescribed Burn Cycle by Management Unit summary+map (2000-2018). Source: Urban Forestry
- High Park Prescribed Burn factsheet. Source: Urban Forestry
- Tallgrass Ontario Fire Factsheet
- Oak Savannah Restoration in Toronto: A Progress Report presentation by Beth McEwen and Jennifer Gibb, City of Toronto, Forestry, Wildland Fire Canada conference October 2010
- Setting Fires and Restoring an American Landscape. Source: New York Times