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