FORT MACLEOD, Alta. – Restoring grasslands after a fire requires years of attention.
There have been few major forest fires in southern Alberta in the last 70 years, so new fires are learning experiences for range managers.
“With anything that happens there is always opportunity to learn something from these fires,” said Michael Alexander, rangeland management specialist with Alberta Agriculture.
Several severe fires since the mid-1990s in the province’s southwest required detailed management plans to help the land recover.
“The rangeland strategies we have applied since differ because the fires were different,” he said at the Oldman watershed council meeting in Fort Macleod Jan. 22.
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Two of the most significant fires in southern Alberta happened in 2003. The Lost Creek fire started July 23 and burned 44,794 acres at the peak of the growing season in the southwest. The Crowsnest Pass was under evacuation alert for 30 days because of it.
This fire burned intensely in the coniferous forest, but the grasslands and deciduous forest were spared from damage for the most part. Riparian areas did not burn if they were surrounded by deciduous forests but if there were conifers, the fire burned to the stream edge.
There were no livestock deaths or serious injuries but there was considerable loss of infrastructure.
“We learned a lot about livestock management during a fire. Cattle in their natural environment seem to be able to move out. Their preferred regions didn’t seem to burn out,” he said.
Fires on dormant grasses that have cured are more serious. The December 1997 fire near Granum, Alta., is an example.
The Poll Haven fire in Alberta was similar to the 1997 event. It burned 4,216 acres at the Canada-United States border east of Waterton Lakes National Park in October 2003. Livestock had already been moved out in what turned out to be a one day, wind-driven fire that burned everything in its path. The 2003 fires had significant effects on the landscape and salvage logging occurred in the winter following the burn.
Range evaluation was done shortly afterward to start a recovery plan.
In the Lost Creek area, the first step was to replace fences, cabins, machinery and corrals. Since little of the range was damaged, deferred grazing was unnecessary, although some changes in rotation and timing were enforced so infrastructure could be repaired.
The Poll Haven area lost fences as well as the grasslands. Grazing was deferred for six weeks. Instead of allowing livestock into the area on July 1, they did not enter until Aug. 15 for two years after the fire.
Stocking rates were reduced by 40 percent the first year and 25 percent in the second year. They remain lower than normal to this day.
In 2006, range resource inventories were done. It took this long because logging was ongoing to salvage as many of the fire-damaged trees as possible.
Range managers learned recovery depends on when the fire occurred and what kind of weather follows. If a drought follows a fire, recovery could take 10 years.
Following these fires, some grass species came back quickly because the trees were gone and there was less competition.
Native varieties like marsh, reed and pine grasses as well as hairy wild rye were the first to emerge in the sites where there had once been forest. These are productive grasses but the grazing period is shortened because the grasses quickly lose their palatability as they mature.
“A lot of those grasses are great for a 20 day grazing period, but on an intensively grazed landscape, that is a challenge,” said Alexander.
