Preparing for ‘Firmageddon’, researchers monitor British Columbia forests for mass kills and droughts

Mike Cruickshank of the Canadian Forest Service waters western redcedars during a drought experiment at the Pacific Forest Center in Victoria. Here, researchers are testing the resistance of different trees to the effects of climate change, as well as the diseases and harsher conditions it will bring to Western Canada.Rafal Gerszak/The Globe and Mail

Pacific Northwest fir trees died in record numbers in 2022 after three years of severe drought and heat waves, according to US Forest Service researchers.

“We call it Firmageddon,” Danny DePinte, who leads the aerial survey program for Oregon and Washington state, said in an interview. “Or, Fir Zombie Land.”

In parts of Oregon, more than half of the fir trees are dead, clearly visible as the evergreen conifer turns brick red. These mortality events are not unheard of, but they are twice as severe as those that have been recorded since the agency began tracking forest health in 1947.

The scale of the loss is alarming, especially from the air.

“When I was flying over, it was the extent of it that pushed us back,” Mr. DePinte said. “You would see it go up one side of a mountain and then it just keeps going.”

Danny DePinte of the US Forest Service has seen the creeping influence of ‘Firmageddon’ in the Pacific Northwest.United States Forest Service

The dead trees it finds are mostly white fir and California red fir, but what kills them also threatens Canadian forests – especially in the interior of British Columbia, where record heat and drought were beaten in 2021 and 2022.

British Columbia’s subalpine region is already under attack: the western fir bark beetle is slowly killing fir trees at the rate of 1% per year, affecting two million hectares of forest each year since 2014.

This is on top of massive forest loss caused by the mountain pine beetle and unprecedented wildfires.

Now the province’s top forestry official fears recent droughts and heatwaves are accelerating mortality.

Subalpine fir, also known as balsam fir, is one of the most common tree species growing in the interior of British Columbia. Like its other true fir cousins, it has a low tolerance for extreme heat and drought.

Tree death in the Pacific Northwest is the inevitable result of hotter, drier conditions that native species cannot adapt to.United States Forest Service

In early December, the province created a stand-alone Ministry of Emergency Management and Climate Change Preparedness to better prepare communities and infrastructure for environmental disasters. But the forest mortality event that DePinte and his colleagues mapped is a warning of how quickly an entire ecosystem can be altered. And while Canadian forest scientists are working on adaptation strategies, there is no silver bullet.

“Our forests are definitely a bit of an indicator of how climate change is affecting not just BC, but the planet,” said BC Chief Forester Shane Berg. “There has been an increase in mortality in our subalpine firs due to the weather conditions we have experienced over the past two summers.”

The province’s solution is to invite forestry companies to harvest where the bark beetle has taken hold. “There’s only one way to actively and aggressively remove them, and that’s to save the trees,” Berg said. “We can attract beetles to a more concentrated area using pheromones, which will put populations in a more concentrated grouping for recovery harvests.”

Much of Canada’s 350 million hectares of forests are vulnerable to climate change, but some species will fare better than others. A Canadian Council of Forest Ministers 2020 Report identifies the tree species most at risk for the foreseeable future: In the boreal forest that stretches from the Yukon and northern British Columbia to Newfoundland and Labrador, the most vulnerable are spruce white and black, aspen and conifers. In the interior forests of southern British Columbia, pines and firs are succumbing to wildfires, insects, drought and extreme weather.

The report warns that climate change is moving faster than most tree species can adapt: ​​”Over the next few decades, the climate of Canadian forests will shift northward at a rate that will likely exceed the capacity of migration of individual tree species. While most tree species can naturally migrate up to a few hundred meters per year via seed dispersal, the climatic conditions under which each species thrives can move north several thousand meters per year.

While a mature forest cannot move quickly, forests felled or burned by wildfire can be replanted with species better adapted to climate change.

Sophie White, right, is a Geospatial Field Technician at the Pacific Forest Centre. She places western redcedar branches into blocks of alder that have been colonized by a fungus, as part of an experiment to measure the spread of a disease called butt rot.

Mr Cruikshank checks some of the 2,487 seedlings in the experiment for foot rot. The fungus, Phellinus weirii, has spread from alder to western redcedar and infested the soil.

Rafal Gerszak/The Globe and Mail

At the Canadian Forest Service’s Pacific Forestry Center, researchers are trying to find the hardiest of each species, in hopes of breeding hardier varieties that can be replanted for future forests.

Forest pathologist Mike Cruickshank studies the impact of stress on trees, and one of his test plots is a greenhouse where nearly 3,000 young trees are subjected to drought conditions to find the ones that have the right genetics to survive.

“We are looking at drought tolerance. We also look at insects and disease resistance. We’re just looking for the best, toughest people we can find,” Cruickshank said.

According to his research, the extreme weather conditions of the past two years will lead to more deaths. It usually takes two years for the damage to show up.

Trees can adapt to heat by drawing moisture from the ground to cool themselves. Or they can survive droughts by developing early in the spring and then going into a dormant cycle. But not both at the same time.

“One of the big problems is the heat and the drought. It’s not just the drought, and it’s not just the heat. It’s the two together. It’s really bad,” Mr. Cruickshank said. “And that’s what we see.”

The future of forests: More from The Globe and Mail

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