THE TOLL ON OUR TREES
Wild weather fallout
Trees don’t live forever. But this year it’s looking like some won’t make it through the year. Registered consulting arborist and professional agrologist Anita Schill says it’s because our trees are stressed and have been using up all their energy reserves repairing damage from the crazy weather we’ve experienced.
“You see this? It’s just horrible. Just look at the damage,” she says as she shows me numerous bark wounds on her hail-damaged chickadee birch.
I’m meeting Schill in her Airdrie yard so I can see for myself how the hail last summer harmed her trees. If you’ve got insurance or cash, a roof can be replaced and a car can be repainted after hail strikes. But money won’t help a tree. A tree has to spend its own energy. Schill is showing me how even the tiniest branches are healing themselves, growing bark over branch wounds — some of the damaged twigs are finer than a pencil.
While the tree spends its energy repairing bark, it doesn’t have extra energy to fight off common pests, so Schill’s trees have been attacked by birch leaf miners this year, for the first time in years. Other birch trees in Calgary are rapidly turning brown and dropping leaves. This is beyond the normal damage you would expect to see as a result of leaf miners.
Schill reminds me of the heavy, limb-busting snow in September 2014, the pounding hailstorms in 2015, and the extended drought this spring, when soil was dry from February to May.
These weather events have taken their toll on all our trees, stressing them further. And the more stress a tree experiences, the more it uses up its stored energy. Diseases and pests move in, and tree growth slows down; leaves brown and drop prematurely, or the tree doesn’t leaf out as expected. This summer many trees are getting their death certificates.
Schill and I look at the brown birch leaves hanging on her tree and littering her lawn. Some large branches are already dead. They have no leaves at all.
“There’s no way the dead branches are going to come back,” she says. “So those branches that are dead? They’re dead.”
Like stressed people, stressed trees need loving care. A 10-centimetre (four-inch) layer of wood mulch spread over a wide area under the tree can limit trampling and reduce soil compaction under trees; and a gentle drip irrigation system waters the fine tree roots far from the main trunk and brings moisture back to the whole tree. Avoid landscape fabrics but consider laying cardboard down between soil and mulch to block weed or turf growth under the tree.