
When heat and drought stress trees, the consequences can be tragic
Global News
Experts say drought-stressed trees can suddenly drop heavy limbs, even on calm days, posing serious risks after tragic incidents on Vancouver Island.
Sometimes it happens without any more warning than the sound of cracking.
A tree physiologist said that several years of repeated drought in British Columbia mixed with heat stress increased the likelihood of branches breaking off, and this could even happen on a “perfectly calm day” without any breeze.
The consequences can be tragic — on July 31, a mother and her five-month-old son were killed by a falling tree on the beach at Cumberland Lake Park campground on Vancouver Island.
Then on Aug. 10, a woman was badly injured when part of a large tree fell on her at Pipers Lagoon in Nanaimo, also on the island.
Peter Constabel, a professor in the biology department at the University of Victoria, said he had seen photos of that tree, and he thought it looked like there was some rot inside it.
“It’s the drought that specifically causes this, and somehow it stresses the tree and drops the branch, or the branch falls. If you get cumulative droughts, of course, it’s gonna weaken the tree overall,” said Constabel, who specializes in the tree health.
British Columbia has suffered years of repeated drought, although conditions are currently rated normal on Vancouver Island, which received heavy rain last weekend.
Constabel said he had seen branches of maple trees and oak trees falling off on the University of Victoria campus, even on a windless day.













