REGIONAL— An updated report on the impact of fire and timber harvest on moose habitat in northeastern Minnesota continues to confirm the importance of fire in maintaining the population of the …
REGIONAL— An updated report on the impact of fire and timber harvest on moose habitat in northeastern Minnesota continues to confirm the importance of fire in maintaining the population of the state’s largest member of the deer family.
While the moose population appears to have stabilized in the region, the 2019 aerial moose survey documents the extent to which just a handful of permanent sample plots, located on sites subject to either recent wildfire or prescribed burning, account for nearly a quarter of the moose sighted during the survey.
Indeed, researchers found 38 moose (the highest of any plot this year) on the permanent Cavity Lake plot, where a 2006 wildfire scorched nearly 32,000 acres of timber near the end of the Gunflint Trail.
The researchers, who include members of the Department of Natural Resources, the 1854 Treaty Authority, and the Fond du Lac band, flew a total of 52 sample plots last January, 43 of which were randomly-selected. The researchers also survey nine permanent habitat plots on an annual basis to better understand how different types of forest disturbance affect moose numbers.
Most of those permanent plots are contained within areas subject to recent wildfire, prescribed burning, or timber management designed to benefit moose. Fond du Lac biologist Mike Schrage has been compiling the results in order to better inform future forest management decisions.
On the five permanent plots subjected to fire, researchers found 102 moose, or an average of 20.38 moose per plot. That’s more than twice the average of 10.0 moose found on all occupied plots surveyed in 2019. And that difference jumps sharply if the five fire-impacted permanent plots are excluded from the overall total of 429 moose sighted in the survey. Among the randomly-selected moose plots, the average number of moose sighted was lower, at just 7.7 animals.
The aerial survey has also documented the extent to which moose reside within former burns. Most of the permanent sample plots affected by fire have portions located outside burn perimeters, but moose are rarely found in those areas. For example, of the 91 moose sighted over the past five years in Plot #41 (located along the north and east side of Trout Lake), roughly half of which was affected by a 2005 prescribed burn, all but three were found within the boundaries of the burn.
Some of the best moose numbers continue to be found in those three permanent plots that were subject to recent large wildfires, including Cavity Lake (38 moose sighted in 2019), Pagami Creek (19), and Ham Lake (19). And the impact of those fires goes beyond the boundaries of the permanent plots. At nearly 90,000 acres, the Pagami Creek fire encompassed several of the existing survey plots and moose numbers appear to have consistently increased in those plots as well. Much of the area around Pagami Creek had maintained a low-density moose population, but their numbers have increased to medium or high density based on recent results.
“That’s the frustrating part,” said Schrage, during an interview with the Timberjay. “Most of our best moose management habitat over the past 10-12 years all happened by accident.”
Schrage notes that while he isn’t advocating the use of large wildfires for moose management, he said it appears that more needs to be done to mimic the effects of fire, most likely through prescribed burning. “If we’re serious about recovering moose numbers, we need to find ways to replicate the effects of large wildfire,” he said.
Meanwhile, Schrage’s report provides some evidence that timber management can also have a positive impact on moose numbers, although the evidence isn’t as consistent or as dramatic as with the effects of fire. The Lima Green permanent plot, located in northern Cook County, has seen significant timber cutting since 2014. Since the start of timber management in the area, moose numbers gradually increased through 2017, although they appear to have declined somewhat in the past two years.
While the data continues to demonstrate that moose benefit from the regrowth in the aftermath of fire, Schrage cautions that it’s not the only type of habitat to sustain high moose numbers. He notes that a portion of the central Boundary Waters, roughly between Sawbill Lake and Knife Lake, continues to sustain high moose numbers despite no timber harvesting or recent fires. He said the forest in that area is mostly overmature, or decadent, in the terminology of foresters— yet moose do well possibly by taking advantage of the burst of shrub growth that occurs as old trees topple from the forest canopy, allowing sunlight to reach the forest floor.
“I can’t stand here and say that logging and fire are always the answer,” he said. “Some places are acting differently.”