Using Prescribed Fire as a Management Tool
By Keana Boere AAg, Agri-Environmental Specialist, Outlook
Along with climate and grazing, fire is an ecological process, or disturbance, that helped shape the prairie landscapes we now have in Saskatchewan. Prior to European settlement in North America, prairie grassland fires were a common occurrence and typically occurred in the mixed grassland region every five to 12 years. Since European settlement, fire activity has been largely suppressed, resulting in a fire deficit across the prairies for the past 150 years. Just as grasslands evolved under bison grazing, native grassland plants evolved to withstand fire, making fire an important tool for maintaining healthy grassland ecosystems.
Prescribed fire is when a fire is intentionally ignited in a specific area, under specific conditions, to meet pre-determined land management goals. Unlike wildfires which can be unpredictable and have severe consequences, a prescribed fire is controlled and used to achieve specific objectives. Months of planning go into creating a fire ‘prescription’, which includes many factors that need to be met before a prescribed fire is started. These factors include wind speed, wind direction, temperature, relative humidity, recent precipitation, moisture content of available dead vegetation (fuel), time of year and time of day, potential presence of species at risk and more. If any factor on the prescription is not met, the fire will not be ignited.
Some benefits of prescribed fire on grassland ecosystems:
- Fire can limit the spread of woody plants in grassland ecosystems. Most woody vegetation has more aboveground biomass compared to grass species, making woody vegetation more vulnerable to fire.
- Removes heavy accumulations of litter (dead plant material remaining from previous years) that inhibits the growth of desired plant species. Heavy litter, or fuel, amounts can also lead to uncontrollable wildfires.
- Fire creates heterogeneity across the landscape, which is important for biodiversity and habitat and contributes to a healthy, functioning ecosystem.
- Fire can cause a flush of nutrient cycling in a burned area.
- New growth following a fire is palatable and attractive to grazing animals.
While prescribed fire offers many benefits to grassland plant communities, there are challenges involved with prescribed fires. There is a risk of fire escaping and causing damage, local air quality is degraded at the time of the fire, bare soil following a fire is at risk of erosion and fire temporarily reduces the amount of biomass available for grazing.
Prescribed fire needs to be completed safely for it to have positive impacts on the landscape. Prescribed fires should only be executed by trained professionals with the knowledge and experience to minimize risk for people, grazing livestock, property and the environment and maximize benefit to grassland plant communities.
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