Why the fall foliage looks less vibrant this year in southern Ontario

The leaves' colour turn came late, and the hues were less saturated this year. Experts point partly to climate change and say more muted falls could be in store.

It’s something people in southern Ontario take for granted – as summer fades, cooler air rolls in and the leaves burst into those fiery, warm hues we love to snap pictures of.

Except that’s not happening this year. Fall is looking … a little dull.

“This year’s October was about four degrees warmer than it was last year,” Sean Thomas told Global News one afternoon at Riverdale Park. The research professor specializing in forestry and environmental change says you can blame this year’s lackluster autumn show, particularly in Toronto, partly on climate change.

“Climate change predictions are for warmer temperatures of course, but also for increased cloud cover,” said Thomas. “That combination — if trees don’t receive the cool temperatures and the high light in the fall at the right time, then they won’t be triggered to form the red pigments.”

According to Thomas, those red pigments are what make those fall colours pop — acting as antioxidants and sunscreen created by the tree to protect its leaves as it extracts nutrients to redeploy for next season. But an unusually warm fall meant the trees did not receive that cold temperature signal to create those red pigments (also known as anthocyanin).

He said there are other factors at play leading to this years’ foliage flop. Toronto having a pretty pronounced urban heat island and sizzling heat waves this past summer have led to foliage scorching — where the extreme heat turns leaves prematurely brown.

Some trees have also been ravaged by mildew and insect infestations this past summer.

“If the trees have lost their leaves, then there’s not the leaves there to turn,” said Thomas.