Controlled Burns

Warning: Do not try this on your own! Only trained professionals should organize and carry out a controlled burn.

New to most of us on the prairies is the sight of a controlled burn taking place. If you see smoke on the prairie, you should be worried! However, the city of Saskatoon usually advertises when a controlled burn will take place, to ensure not too many calls will go to the fire department. If you have not heard of a controlled burn taking place, please do call 911 to report the fire. Better to be safe than sorry.

Prairie habitats have been shaped by both humans and nature. The practice of controlled burns is not new. Indigenous peoples managed the land for millennia, and one of their management practices was to burn small portions of the prairie in the spring, before all the snow had melted. This demonstrates how humans are important parts of ecosystems, if they consider other species and take only what they need. Burning selected areas on the prairies was done partly to increase safety from potentially uncontrolled wildfires. Grass fires can start quickly and spread rapidly, burning hotter and moving faster than forest fires, making them highly dangerous. But the small, controlled fires also rejuvenate the prairie, sparking new growth of grasses, medicinal plants, trees, and shrubs and thereby increase wildlife habitat diversity. The ash from the burned leaf litter and fallen branches quickly moves into the mineral bank in the soil, to be taken up by new plant growth.

Crocuses post burn. Photo credit: M. Mickelson

Prescribed burning is a carefully planned event, controlled and managed now by restoration professionals. A controlled burn removes accumulated leaf litter and branches dropped from trees and shrubs. Removing this tinder dry material helps prevent or reduce uncontrolled wildfires. Controlled burns also help restore native prairie. Restoration specialists are considering the overall health of the prairies.

Wildfires are a threat to those living on the prairie; however, wildfires are also nature’s cleanser for both grasslands and forests, but because of human involvement, controlled burns are now used. Burns help control plant diseases, such as black knot fungus, and juniper rust. Juniper rust (also known as cedar rust, or apple-cedar rust) spreads from junipers to other species like saskatoon berry bushes. Juniper rust produces rust-coloured galls, about one centimeter in diameter, on juniper plants. When the spores blow in the wind to saskatoon berry plants, the rust colour shows up on the leaves in early spring as well as on berries which will develop rusty spots with little spikes that make the berries not palatable. Fires can also reduce insect infestations, or populations of ticks. Thus, fire helps reduce insect- and tick-borne disease transmission to animals (including humans) by reducing the number of organisms that spread the disease.

As you can see, in contemporary times, controlled burns are completed for similar reasons to those of the First Peoples. However, currently, controlled burns are also used to burn off and reduce invasive plant species. After a burn, native plants are favoured over introduced ones, since the native varieties have evolved strategies for surviving burns. Native grasses have much deeper root systems than introduced species, with the bulk of the plant remaining underground. This gives native grasses an advantage for fast regeneration. Native plants take up the minerals provided by the ash and thrive in the sunlight that is suddenly much more available than before the burn. Prescribed burning thus gives native plant species the opportunity to flourish, while knocking back the introduced and invasive species.

Controlled burn at Wanuskewin Heritage Park. Photo credit: Sandra Walker

Prescribed burns can be used as part of a diverse land management strategy, with application depending on goals and the season in which the burn occurs. Spring burns help restrict the growth of invasive species, while fall burns tend to promote the growth of native wildflowers (in the next spring). Fall burns “scarify” native plant seeds; some seeds are more likely to grow after the stress of burning, which can crack the seed coat to germinate in the next spring when the ground becomes warm. The burned areas, with little plant cover, allow the snow to melt directly into the soil, rather than running off towards a lower area, or a slough. The blackened burned areas absorb more heat from sunlight, stimulating the growth of warm season native grasses. Because the burn will always be spotty, with most of the area burned, but some wetter areas which don’t burn, or, in the spring, some areas still with drifts of snow on them (again, not burning), the ambient air temperature does not get too high. And, as described above, this patchwork of regrowth allows for greater species diversity.

Check out an area where there has been a controlled burn. Watch for bird nests in the clumps of long grass, and check for grazing ground squirrels. Examine what plants emerge first in the burned area and check to see if the species variety is similar for a defined burned area, versus the same size of remaining clumps of long grasses. Look for signs of wildlife in the two different kinds of area. Do you see signs that sharp-tailed grouse have created a lek (a dancing ground) through their dancing, and are these leks in long grass or the short grass that emerges after the burn? In the wooded areas, watch for signs of fungus – black knot fungus in choke cherry trees, and juniper-rust in saskatoons. Has the burn cleaned out some diseased plants? Also, you can do a check for ticks in the burned area versus the long grass. Or any other comparison you wish to know about!

Do not light your own fires! Grass fires can quickly get out of control. Those who are trained in burning the prairie have the knowledge, skill, AND the equipment for controlling the fire.

– By Sandra Walker and Wade Falk