DATE: November 17, 2018
SNIP: Last year, 12,812 hectares of B.C. forest was sprayed with the herbicide glyphosate. It’s an annual event — a mass extermination of broadleaf trees mandated by the province.
The eradication of trees like aspen and birch on regenerating forest stands is meant to make room for more commercially valuable conifer species like pine and Douglas fir.
But experts say it also removes one of the best natural defences we have against wildfire, at a time when our warming climate is helping make large, destructive fires more and more common.
When aspen and other broadleaves are allowed to flourish, they form “natural fuel breaks” if their leaves are out, according to Lori Daniels, a professor of forest ecology at the University of B.C. That’s why aspen stands are often referred to as “asbestos forests” in wildfire science circles.
The province’s Forest Planning and Practices Regulation states that when a block of forest is regrowing after a wildfire or logging, broadleaves can’t make up more than five per cent of trees, or two hectares — whichever total is smaller. The concern is that trees like aspen will out-compete conifer species, which are the lifeblood of the timber industry.
If there’s too much aspen, the block must be sprayed with glyphosate, a chemical known more familiarly as the active ingredient in Roundup. Over the last three years, 42,531 hectares of B.C. forest have been treated with the herbicide.
“At the end of the day, we have rules that make fire-resistant trees illegal in our forests. That’s just nuts,” James Steidle, a member of the anti-glyphosate group Stop the Spray B.C., said.
Aspen naturally thrives after a forest has been cleared by logging or wildfire. Their root systems can survive for thousands of years underground, and they’re capable of sprouting new clone trees as soon as there’s enough sunshine and moisture.
Glyphosate doesn’t just kill aspen trees — it can also destroy the root system.
“When you spray a forest, that’s going to last for the lifetime of the forest,” Steidle said.
According to Lori Daniels, a professor of forest ecology at the University of B.C., that’s a major loss in a province that struggling with how to prepare for wildfires after two record-setting seasons in a row.
Trees like aspen naturally have a higher water content and don’t usually contain the volatile chemical compounds that can make trees like pine so flammable. They also provide more shade, which creates a cooler, more humid environment in the understory, Daniels explained.