Fire that ordinarily helps the boreal black spruce forests now threatens them too

12:37 p.m. PDT Oct. 31, 2021

Swan Lake Fire Alaska
Black spruce burning in the Swan Lake Fire near Mystery Creek southwest of Anchorage, AK in 2019. Alaska DNR photo.

This is an excerpt from an article at Canadian Broadcasting Corporation.

Warmer, drier conditions that lead to more frequent fires in Canada’s vast boreal forests are threatening the dominance of black spruce trees that for thousands of years thrived in a healthy relationship with forest fires.

Black spruce trees and the thick layer of peat they take root in are great fuel for the fires. So typically, every 100 years or so, a fire would sweep through and take out a stand of these iconic boreal trees.

That same fire would warm up the black spruces’ waxy cones, releasing its seeds that would allow the black spruce forest to regenerate.

But in recent years, climate change has undermined the healthy relationship between black spruce trees and forest fires. More frequent wildfires are pushing large areas of black spruce forests past their recovery point.

As a result they’re being replaced by other species, and sometimes the forest doesn’t regenerate at all.

“We do see evidence of shifts away from black spruce dominance in more than one third of the sites,” said Jennifer Baltzer, the Canada Research Chair in Forests and Global Change at Wilfrid Laurier University.

This shift away from black spruce dominated-forests could have far reaching implications for the wildlife that depend on them — like caribou — and for the massive amount of carbon these forests store underground.

Baltzer is the lead author of a new study that analyzed more than 1,500 former burn sites across the North American boreal forest, between 1989 and 2014.

“This is one study, in a growing body of evidence, that we’re pushing ecosystems toward these tipping points that we don’t really know what comes next,” Baltzer told Quirks & Quarks host Bob McDonald.

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Author: Bill Gabbert

After working full time in wildland fire for 33 years, he continues to learn, and strives to be a Student of Fire.

3 thoughts on “Fire that ordinarily helps the boreal black spruce forests now threatens them too”

  1. Hi Bill and Readers of this article,
    I read: “We do see evidence of shifts away from black spruce dominance in more than one third of the sites,” said Jennifer Baltzer, the Canada Research Chair in Forests and Global Change at Wilfrid Laurier University. This shift away from black spruce dominated-forests could have far reaching implications for the wildlife that depend on them — like caribou — and for the massive amount of carbon these forests store underground. Baltzer is the lead author of a new study that analyzed more than 1,500 former burn sites across the North American boreal forest, between 1989 and 2014.” But I also read: “Black spruce trees and the thick layer of peat they take root in are great fuel for the fires. So typically, every 100 years or so, a fire would sweep through and take out a stand of these iconic boreal trees.”
    I lived 30+ years in northern Minnesota, which state has eight million acres of basically level (flat) peat lands whose depth is more than eight feet thick. (I believe I remember the 8,000,000 correctly) But I absolutely know that any black spruce growing on this thick peat is maybe a 100 years old and has a diameter maybe great as four inches. This because there is a lack of the mineral nutrients necessary for the growth of all trees and many plants.
    The photo of this article is clearly not that of a peat bog. Enough said???

    Have a good day, Jerry

    1. 8 million acres in Minnesota is close, I googled it and got 6-7 million acres of peatlands. I worked as a forester for 14 years in northern Minnesota and I fought a forest fire along the Alaskan Highway in northern BC and southern Yukon, Canada. Peatlands in Minnesota have a wide variety of vegetation growing on them. From open brush lands or muskeg to “stagnant” spruce, cedar and tamarack stands to commercial stands of spruce and tamarack. The spruce stand you see burning in the photo is obviously a commercial stand of spruce with diameters of possibly 6-8 inches or more and may even be an upland stand of spruce not growing in a bog per se. The fire I fought had a mixture of spruce and pine in the upland with a 12 inch thick duff or peat layer and also spruce growing in poorly drained bogs with deep peat. Those bog trees were more stunted and some resembled the stagnant spruce bogs of northern Minnesota. Those stagnant stands were usually a result of too much water, poor drainage and not just lack of mineral nutrients. I didn’t read the whole CBC article but it is very believable that intense fires that destroy the whole crown and cones of the trees and burns deep into the peat could affect the natural reforestation of those stands, especially if they reburn in a subsequent fire. The reburns are affecting natural reforestation of conifers in Oregon also, where I worked as a forester and firefighter for 26 years after Minnesota.

      1. I’m going to respectfully disagree, that this stand outside of Anchorage is a commercial stand. I lived in the interior of Alaska for over 30 years, most of that as a wildland firefighter and traveled the highway to the Canadian border to Beaver Creek, thru the Yukon Territories, British Columbia either down thru Montana or through the Frazier River Valley to Washington, Oregon or N Idaho. This is what much of the landscape, and boreal forests look like. There was a 365,000 acres fire that burned thru central eastern Idaho called the Clear Creek Fire in 2000. It was so hot, in many, many of that acreage no trees have come back. In a few areas there is growth, but the Ponderosa Pine or Douglas fir is only 4-5’ tall. This is the same lack of growth from very hot fires as the fire that burned in Sula, MT also in 2000. The boreal forest in Alaska and the Canadian west is very different than N Minnesota.

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