Trinity Bellwoods tragedy: How to spot signs of decay in the trees

Toronto parks staff are still investigating the health of atree in Trinity Bellwoods Park under which a man in his 30s died Friday after being hit by a falling tree branch.

• Toronto parks officials, police investigating after falling branch kills man

There's been no indication that there was anything wrong with the tree. Thatarea of the park has since been re-opened and witnesses said the treeappeared lush and leafy.

A green branch dispels the possibility of deadwood, an arborist said Saturday, as he took a reporter on a tour of High Park's trees. A barren branch, however, signalsthat part of the tree could beill or dying, Aaron Hill said.

Hill, the owner of Toronto Tree Removal, said homeowners should regularly check the roots, branches, and "main union" when assessing the health of their backyard.

The main union

One of the first signs of decay can often be spotted at what's known as the main union,the area where the tree's major limbs begin to branch off from the trunk, Hill said.

If there are plants nestled in the arms of the diverging branches, that can mean there's decay or ahollow forming in the tree, the arborist says.

"At some point in the future, one of the limbs could fall, especially under the stress of a wind storm," Hill says.

Basal rot

Root damage acts asanother culprit and often an invisible one.

Healthy roots hold up the tree, but if they've been injured by landscaping or nature they no longer form a strong support system, Hill said. Thedamaged base is known as basal rot.

"You may not see any signs of it whatsoever until the tree topples over," he said. "But the chances of basal rot can be increased by bad landscaping decisions."

• Man killed trying to protect wife from falling tree branch in Trinity Bellwoods Park

There are swaths of aging trees around the city, Hill said, pointing to the Norway maples that saw a mass planting here several decades ago.

"It's the beginning of a gradual period of decline, which is true for a lot of mature trees in Toronto," he said.

Hill wouldn't speak directly to the incident in Trinity Bellwoods Friday, which remains under investigation by both the city and the police.