Prescribed Burning - Environment Canada

Prescribed burning is the use of fire as a management tool under specified conditions for burning a predetermined area. It implies planning and care.

History tells us that when conditions on prairie grasslands were conducive to burning, lightning strikes and fires set by Plains Indians burned over vast areas. Therefore, prairie grasslands are adapted to fire.

It is a fact that some grasslands in the Canadian prairie cannot be maintained without fire. In areas where moisture conditions meet the needs of trees and shrubs, it is difficult to control these plants without mechanical, chemical, or fire disturbance. Fire is the cheapest, most environmentally-friendly method of controlling woody growth.

On the other hand there are risk factors with burning that are difficult to control. The following provides ideas on possible applications of burning but does not include all the guidelines you will have to follow in carrying out a burn. Do not proceed with burning until you have consulted with an experienced practitioner familiar with conditions in your area.

Effects of Prescribed Burning

While fire is rarely used in the Canadian prairie region to maintain or improve grasslands for livestock grazing, there is a place for this technique. It has been tested with excellent results at the University of Alberta Ranch near Kinsella as a cost-effective method to clear Aspen poplar stands and expand the Fescue grassland for cattle grazing.

Prescribed burning fits in well with rotation-grazing systems. Burns can be restricted to fenced paddocks so that the whole pasture does not have to be burned and cattle can be kept off the newly-burned area until the grasses have had a chance to re-grow.

Regional Applicability of Prescribed Burning

Landowners and researchers know that fire may be necessary to reclaim or maintain grassland in the moist regions of the Mixed Prairie, the Fescue Prairie, and the Tallgrass Prairie. In the arid reaches of the Mixed Prairie where annual precipitation is less than 40 centimetres per year, the need for fire has not been determined. In those areas, woody encroachment is not a problem and burns are certain to have a prolonged detrimental effect on forage production and soil erosion.

Experience with prescribed burning lies largely with managers of Crown land. Traditionally, these managers have had sufficient resources to conduct burns, they are under fewer liability constraints, and they have had to find economical methods to manage vegetation on large tracts of land. Individual landowners should not attempt to burn without examination of their plans by a management specialist.

Open ground created by fire attracts Burrowing owls and ground-nesting shorebirds which will not normally occupy tall vegetation.
Photo: D. Wood

Timing Prescribed Burning

Safety factors and plant species responses will determine when to burn. You will need expert advice on both of these considerations.

All plants are most vulnerable to defoliation during their most active period of growth, when the plants energy resources are lowest. As this varies among species, tailor any burning plans to the species of concern in your management objectives. Grasses have growing points in the basal crown near or below the ground surface, so they are better adapted to fire than woody plants or forbs. Some grasses grow primarily in the cooler period of spring or fall (cool-season grasses) while others grow best during the heat of the summer (warm-season grasses). Timing the fire can be managed either to favour or to control these different groups. Knowing which leaf stage or plant height in relation to burn prescription will achieve your particular burn objective will be critical to proper planning.

Do not burn in a drought year. Plants respond more slowly when drought-stressed, and basal crowns and roots can be damaged when the soil is not moist. Overall, burning when it is too dry will increase the soil-erosion hazard.

Burns should be conducted only on the basis of accurate spot weather forecasts and a strict set of criteria for acceptable weather conditions. Prevailing wind direction for your area will determine ignition plans and placement of fireguards. Changes in wind direction can result in poor burns or cause fires to burn out of control. Arrange for spot weather forecasts well in advance to ensure you know conditions the day before you burn, the day of the burn, and the day after. Belt weather kits can be purchased to help you determine whether or not it is safe to burn.

Provincial Fire Regulations

Essential equipment for prescribed burning includes protective clothing for personnel, firewater pumping capability, hand-held wetting devices, rakes, shovels, rubber flappers, and a drip torch for safe ignition. Farm equipment such as chemical sprayers, mowers and cultivators can be used for fire control and construction of fire guards.
Photo: E. Driver, Canadian Wildlife Service

Each province has established regulations governing burning permits, fire season, fire control, personnel and equipment requirements, and liabilities. In order to ensure a safe burn, persons responsible must comply with these regulations.

Information on burning techniques, safety requirements, fire suppression in case of an escape, equipment, personnel, legal obligations, and notification requirements can be obtained from your local municipal or forestry fire control officer.

Frequency of Burning

Historical records reveal that burns did not occur very often under natural conditions in a given area. To maintain a healthy grassland, it is not likely that landowners would need to burn more often than once every 5-10 years, depending on which precipitation zone their land is located in. The drier the environment, the lower the frequency of burning required.

If exotic plants or woody invaders are to be controlled, one burn may not be enough. Two or more burns every two or three years are usually required to reduce the abundance of such plants. These are termed reclamation burns. Periodic additional burns needed to prevent invasion are known as maintenance burns.

In the Tallgrass Prairie dominated by warm-season grasses, a maintenance burn every 3-5 years in late May to late June, depending on when spring arrives, gives best results. In the Mixed and Fescue Prairie, earlier spring burns ensure that the dominant cool-season grasses are not damaged. One maintenance burn every 5-10 years would be sufficient.