It’s something the people of southern Ontario take for granted – as the summer fades, cooler air comes in and the leaves take on those warm, fiery hues we love to take pictures of.
Except that won’t happen this year. Fall looks … a bit dull.
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“October this year was about four degrees warmer than last year,” Sean Thomas told Global News one afternoon in Riverdale Park. The forestry and environmental change research professor says this year’s lackluster fall spectacle, particularly in Toronto, can be blamed in part on climate change.
“Climate change predictions are for warmer temperatures, of course, but also for more cloud cover,” Thomas said. “That combination: If the trees don’t get the cold temperatures and high light in the fall at the right time, they won’t be activated to form the red pigments.”
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According to Thomas, those red pigments are what bring out those fall colors, acting as antioxidants and sunscreen created by the tree to protect its leaves while extracting nutrients to redeploy for the next season. But an unusually warm drop meant the trees didn’t get that cold temperature signal to create those red pigments (also known as anthocyanin).
He said there are other factors at play leading to this year’s foliage failure. Toronto, which has a fairly pronounced urban heat island and scorching heat waves last summer, have caused foliage to burn, where extreme heat causes leaves to turn prematurely brown.
Some trees have also been devastated by mold and bug infestations last summer.
“If the trees have lost their leaves, then there are no leaves to turn,” Thomas said.
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Additionally, he notes that some of the brown seen this year is due to Toronto being home to many non-native trees, such as the Norway maple, which don’t actually produce fall colors.
“So when you look at the ravines and Toronto, a lot of what you see is not native species. It’s invasive Norwegian maple and they don’t spin. “
Thomas says that in an average year, in late September / early October, the leaves will start to change, reaching maximum color at the end of that month before falling.
But this year, many trees have clung to their summer green well into November, and some have completely lost their fall color change.
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Warmer temperatures are also being delayed when trees drop their leaves. The canopy of a tree in Pickering had mostly bare branches in early November last year, but this year it still showed some lush green in late November.
The duller fall colors are leaving some viewers less than excited, especially when considering that climate change could make it the new norm.
“I mean it sucks,” said a young Ajax couple. “Because you go from being a kid and you see it so bright and now you see the change …” the woman’s voice trailing off sadly as she points to the trees in Riverdale Park.
“It’s very sad,” said a man sitting on a bench in the park. “It is a very sad consequence of total irresponsibility … everything must be done to help nature because it is all we have.”
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