Tracking the mountain pine beetle threat with a drone and a butterfly net

This story is part of the World on Fire series, a five-part podcast that takes us to the front lines of out-of-control wildfires in Canada, Australia and California. Recorded during the COVID-19 pandemic, each episode examines what it takes to find hope in the midst of fear and destruction. Wildfires cost us our health, our homes and our communities, yet people everywhere rebuild and not just survive — but thrive. 

Devin Goodsman is waiting for the day developers engineer radio collars small enough to track the movements of a five-millimetre-long mountain pine beetle.

In the meantime, he is relying on a more rudimentary contraption to capture beetles charting a flight path through the lodgepole pines of Western Canada. 

"We have a drone fitted with a butterfly net," Goodsman said in an interview with CBC podcast World on Fire. 

"The plan is to catch them using an unmanned aerial vehicle at various locations, including above the canopy." 

Goodsman, an entomologist with the Northern Forestry Centre in Edmonton, is working to better understand the movements of the beetles above the forest canopy — research he hopes will help inform wildfire management practices across Alberta.

Goodsman has been tracking the beetles' movements throughout Alberta. One of his test sites is just a few metres inside the eastern gates of Banff National Park, in a stand of infested trees. 

"I have a bunch of papered trees here, and the idea is that when the beetles emerge from that tree they'll be forced to chew through the paper," Goodsman said. "And white paper — if it's the right kind of white paper — it will fluoresce under black light. 

"The beetles that we've captured, we can look at them under a microscope with a black light shining on them and we'll see really fine dust from the paper." 

'Really good beetle homes'

The beetles have become a powerful menace in the fight against wildfires.

Infestations have infected more than 16 million hectares of B.C. forest. The beetles have crossed the Rockies into the western edges of Alberta, turning swaths of trees a sickly rusted red — trees that could become a tinderbox during spring wildfire season. 

The beetles survive by burrowing beneath the bark of pine trees and mining the phloem, the layer between the bark and wood. After the eggs hatch, the grub-like larvae spend the winter feeding under the bark before they mature in spring. Trees can die within weeks.

"The populations built and then they started spilling over into Alberta," Goodsman said. "And by that time they had already reached the densities that are required to attack very well defended trees. So it just kind of steam rolled through our forests.

"We don't do a lot of harvesting in our national parks, so trees tend to get to that old age where they're really good beetle homes." 

Goodsman's work focuses largely on the dispersion of the beetles. Each spring, swarms of the bugs take flight, searching for new trees to attack.

But these annual pilgrimages above the forest canopy are not well understood, making the insects movements — and future infestations — difficult to predict.

That lack of understanding means there is little clarity around how to best to quell infestations — and how much old infestations are contributing to new ones. 

Should infested forests be clear-cut, levelled with prescribed fire or left untouched?

"They fly from areas that are densely attacked to areas that are less densely attacked, and we don't really understand the mechanism for this," Goodsman said.

That makes the dispersion study even more important for forestry officials preparing for future outbreaks and trying to ultimately slow the beetles' crawl across Western Canada.  

Do you manage or burn stands that have a really high levels of mountain pine beetle, or do we give up on them?- Devin Goodsman

"This has really important ramifications for the patterns of the damage that we see across the landscape. And it's very difficult to make management decisions in this context. 

"Do you manage or burn stands that have a really high levels of mountain pine beetle, or do we give up on them? 

"My opinion is that these infested stands are important sources of pine beetles elsewhere, so there might be some benefit to be gained from managing them." 

Much like the infamously hard-to-kill cockroach, the mountain pine beetle produces a sort of antifreeze in its blood, allowing it to withstand the cold.

Although his work is still in the preliminary stages, it's clear that some populations are able to avoid freezing to death during the most brutal cold snaps.

"Many of the beetles that we're removing from these trees are wiggling and are doing just fine," Goodsman said. "Some places are these little refuges where they surprisingly might do quite well. They're hiding out." 

'A perfect storm'

Chris Stockdale, a fire research scientist with the Northern Forestry Centre at Natural Resources Canada, said wildfires spread slightly faster in forests where the mountain pine beetle has laid an area to waste.

By killing trees, the pine beetle leaves behind a forest floor full of dead wood and pine needles, dry fuel ready to spark. Fires that start in the stands are likely to spread with increased intensity. 

The beetles' destruction paired with years of fire suppression efforts have left older, preserved stands of trees at elevated risk, Stockdale said.  

The B.C. Ministry of Forests said there were some areas of overlap between the wildfires and beetle-attacked forests. In 2017, it's estimated that two-thirds of the fires occurred in green stands and about one-third in dead stands. 

The ministry said more research is needed.

We suspect some of these places will not regrow forest at all.- Chris Stockdale

Stockdale is working on a comprehensive literature review of all research to date on the connection between wildfires and pine beetles. 

The largest gaps in the research relate to questions about the future, he said. 

Over time, it's unclear how landscapes touched by the pine beetle, fires and the changing climate will recover.

In some places, a forest may not take root again, Stockdale said. 

"It's really unclear at this stage, because we've never seen something at this scale, what the long term effects are going to be on this ecosystem.

"And we highly suspect that, in places where fire suppression has put forests where they didn't used to be, and now really intense fires have burned, we suspect some of these places will not regrow forest at all and they'll remain as grassland.

"It's kind of a perfect storm of climate, fire suppression and human activity. All these things come together and that's what sets things in new directions. It's a reminder that nothing is static."