Hot, dry summer could lead to shortened window for seeing fall foliage in Ontario

TORONTO — The vibrant colours of Ontario’s fall foliage could have a shorter display than expected this year after a hot and dry summer.

Environment Canada senior climatologist David Phillips said the trees in eastern Canada could soon show the effects of a hotter and drier summer than normal, and they may not hold on to their leaves for very long as fall colours arrive.

“We’ve seen more days above 30 (degrees) this year in some places than the previous three summers. It’s been great beer-drinking weather, but not necessarily great for trees,” he said.

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While the trees may not currently show signs of stress, they’ve had a difficult few months, with some parts of Ontario and Quebec getting 50 per cent or less rain than normal. Phillips said the dry conditions combined with hot temperatures are a “double whammy” for the foliage, and the autumn colours this year might have a shorter, less vivid lifespan.

Evidence of the difficult summer could even show itself next year, when the foliage turns green again after the winter, Phillips said.

“We went through those five weeks during the dog days of summer when you normally reach your highest temperatures – we were seeing no rain at all. In many ways, that period when trees and crops are growing feverishly at the peak of their growing season, they were probably under greater stress,” he said.

“The trees are not happy with this kind of stress. They may be crying uncle this fall.”

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Phillips said that a few rainy days over the past week may have helped, including significant rainfall in many parts of Ontario on Tuesday. But the long-term lack of moisture, combined with the sustained intensity of the summer’s heat, have already taken a toll.

Phillips added that the Niagara region has been hit especially hard, seeing only about a third of the typical rainfall for the summer, even after taking precipitation from the past week into account.

Eastern Canada will likely see the leaves changing earlier this fall, Phillips said, and if storms with strong winds roll in, they could put a faster end to the season.

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“My sense for people viewing the colour-change season is don’t procrastinate. When (the leaves) do turn in mid-September, late September or early October, don’t think that they’ll be there the next week after that,” he said.

There will likely be good weather for watching the autumn leaves, with forecasters predicting warmer temperatures than normal in September and October. Phillips said it’s too early to tell how much rainfall there might be in the coming months.