New ‘sooty bark disease’ affecting trees on Vancouver Island

New ‘sooty bark disease’ affecting trees on Vancouver Island
An example of a tree affected by sooty bark disease is shown. (Natural Resources Canada)

A lonely maple tree got a big trim to help stop the spread of a disease on Vancouver Island this week.

On Thursday morning, the City of Victoria used a chainsaw to cut through a sycamore maple tree on Dallas Road.

The removal was part of an effort to curb a recently discovered disease, known as sooty bark disease, which was first discovered in southwestern B.C. in 2022.

Scientists with the province and Natural Resources Canada now suspect the disease is more widespread across British Columbia, including on Vancouver Island, and is more visible because of increasingly hot and dry summers, which weaken trees.

Sooty bark disease affects trees from the inside out, according to Canadian Forestry Service scientist Joey Tanney.

“The fungus, it grows within the wood of the tree and then it produces spores,” he said. “So it spreads through airborne spores.”

“It produces an immense amount of spores, and it looks like soot on the bark, so it looks like this black crust that’s emerging through the bark,” said Tanney.

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An example of a tree affected by sooty bark disease is shown. (Natural Resources Canada)

The disease can affect several types of maple trees, including sycamore, Norway and bigleaf maples. The spores tend to resemble “soot,” which gives the disease its namesake.

Tanney says that out of the 250 sycamore trees in Victoria, 30 of them most likely have the disease.

Scientists are asking southern Vancouver Island residents to be on the lookout for the tree disease.

Signs that a tree may be affected by sooty bark disease include, drooping, shortening or self-pruning branches, shoot mortality, sticky ooze coming from the trunk of the tree or pruning wounds – and bark cracking or detachment, with patches of discolouration underneath the bark.

If you think you may have found a tree with sooty bark disease, you can submit your findings to the iNaturalist website.

RELATED: A ‘new’ tree disease threatens British Columbia’s Douglas firs

With files from CHEK’s Tchadas Leo

Adam ChanAdam Chan

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