Forests killed by pests, fire need protection: experts
Forests that are burned or killed by insects shouldn’t be cleaned of debris and instead need protection, a report from a conservation group says.
Hilary Cooke, a scientist with Wildlife Conservation Society Canada and co-author of the report, said the motivation for the report is the increasing interest in using biomass, or dead trees, to produce cheap energy in Yukon.
While their research focused on Yukon’s forests, it gathered lessons from similar woodlands across the country, she said.
Cooke cautioned that cleaning out such forests should be done carefully.
“There’s this perception that when a fire goes through a boreal forest we lose the trees or when the insects eat the trees that it’s a loss somehow, it’s a waste,” she said. “But in fact boreal forests are naturally evolved with this cycle of wildfire.”
The concept of “salvage” logging suggests taking trees that otherwise have no value, but even dead trees play an important role in the ecosystem and overharvesting can cause damage to habitats that are valuable for species, says the report.
Cooke said the report highlights that fire is a natural part of the life cycle and when it kills trees they become food for beetles, which are eaten by woodpeckers, which create tree cavities used by other species.
“So there’s this whole cycle that happens with this natural disturbance process.”
Yukon saw 67 wildfires covering an area of more than 856 square kilometres last year.
There were 115 wildfires in 2017 that consumed almost 4,000 square kilometres of forest and land.
No one from Yukon government returned a request for comment on the study.
The spruce bark beetle has been the most damaging forest pest in Yukon in recent decades, responsible for killing about 4,000 square kilometres of predominantly mature white spruce, the report says.
The complex relationship between natural disturbances like fire or insect outbreaks means that rather than seeing the areas as “dead zones” or places with “wasted wood,” those forests should be seen as an integral part of the boreal ecosystem that need to be treated with the same care as mature forests, the report says.
However, Cooke said climate change is altering fire regimes and ramping up insect outbreaks, which is something to contend with when thinking about regional forest management.
“We need to recognize that there are values in recently burned and beetle-killed forests just the same way there are in mature forests. And that we can’t just think of them as places to go in and clear throughout,” she said, adding that they should be managed in such a way that allows birds and plants to come back.
The first five years after a fire are the most important and forests should be left undisturbed to regenerate, she said.
“I am recommending 50 per cent of Yukon’s recently disturbed forests be protected so that those species that depend of them, those beetles and trees and woodpeckers and moose and hares so that they have the habitat,” Cooke said.