Tree migration could help B.C. forests better prepare for climate change, says UBC study

Old growth Douglas fir trees stand along the Salmon river Trail on the Mt. Hood National Forest outside Zigzag, Ore. (AP Photo/Rick Bowmer, File)

A new study has pinpointed strategies to help local forests adapt to climate change, as this month’s devastating blazes in Los Angeles raise further concerns about the potential wildfire risks in B.C.’s own backyard.

Produced by researchers and students at the University of British Columbia, the eight-year study found ways forest ecosystems can be better prepared for the climate threat, with a focus on mitigating the loss of the Douglas fir tree.

The Douglas fir, which grows throughout B.C., plays a crucial role in biodiversity conservation.

Renowned B.C. forest ecologist, UBC professor and co-author of the study Suzanne Simard, said the project looked at the process of relocating Douglas firs that are already adapted to dry, hot weather, farther north.

“It’s just people giving a helping hand to help plants move, which we’ve done for a long, long time, so that we can help these seedlings keep up with how rapidly it’s warming,” said Simard, co-author alongside UBC student Thomson Harris.

Opting for a two-pronged approach, researchers also explored how various routes of harvesting and regenerating forests would affect the migrated seedlings’ attempt to grow in the face of climate change.

Researchers tried various avenues, from clear-cutting to retaining larger densities of the tallest Douglas fir trees, said Simard.

“We tested all these different ways of leaving old trees behind, from leaving nothing all the way up to leaving everything, and these different retention levels in between,” she said, describing how the study found varying results across B.C.’s diverse climates.

Across all the regions, seedlings were the most vulnerable to climate extremes after forestry clearcutting, once all of the trees had been axed. Within the drier regions more susceptible to frost and drought, seedlings survived more when 30 to 60 per cent of the tallest trees in the canopy were left behind, she said.

“When you have harsh conditions, as the climate changes, leaving that canopy of trees is going to be more and more important to protect the seedlings from the arid and dry conditions.”

The findings are crucial, said Simard, as the populations of Douglas fir that are still yet to be adapted to the future climate conditions are looking at an incredibly uncertain future.

“It’s a really big deal. In the next 100 years, this species, a dominant tree in the Interior of British Columbia, is going to be maladapted pretty much throughout its range,” she said.

“They are going to be stressed out. They are going to be getting infections and insect infestations because they’ll be putting more energy into trying to survive under those conditions, that they won’t be able to fight [them] off.”

With the Douglas fir - a tree already adapted to surviving fire, with thick bark and deep root systems - Simard said keeping this species prolific is particularly important in the fight against the mounting threat of blazes in B.C, with it “highly likely” that fires similar to those that have wreaked havoc in L.A. could affect communities locally, she said.

“Almost all communities in British Columbia, other than the big ones like Vancouver and Victoria, are right in the forest, so we’re all at risk. These things are going to start happening more and more and more, and we’re going to lose more communities, probably this summer,” she said.

There is a balance between intervening with nature and letting it take its own course that has to be concerned with projects such as this one, but given the rapid pace of climate change, if humankind doesn’t step in now, “we’re going to be in a lot more trouble,” said Simard.

The forest regeneration and seedling migration project is one that requires funding, effort and planning that Simard hopes everyone can assist with. Whether that be through the act itself, or simply becoming more aware of the threats B.C.’s environment is facing.

“Everybody should be engaged in some way in the climate change mitigation right now, because we’re all being affected by this,” she said.

“Be aware, be engaged, and get to know what’s going on in the forests around you. Pretty much every community either has a plan, or they’re implementing a plan, on reducing risk around their community,” she added.

“There’s a lot of work that needs to be done. It has to be done carefully, and we need people to help out.”