## TorontoS Trees are Changing Colour Earlier Than Usual – Hear’s Why
Toronto‘s trees are exhibiting fall colours approximately a week earlier than normal, a shift experts attribute to increasing environmental stress, especially drought conditions exacerbated by climate change.Observations from field teams and biologists indicate this early change isn’t always a vibrant display, with some trees shedding leaves directly rather than transitioning through typical autumn hues.
According to Ryan Maddalena, a horticulturalist with the City of Toronto, trees respond to heat stress and drought, but prolonged conditions can lead to visible signs of distress. “You might see curls or brown tips from that heat stress and that drought,” he explained. ”And if that’s prolonged through the season and they aren’t able to recover, you will see them start to drop their leaves a little bit earlier as a response to those drought conditions.”
Sue Hayes, Senior Manager of Terrestrial Inventories and Monitoring at the Toronto and Region Conservation Authority (TRCA), confirms similar observations.
The early colour change isn’t merely an aesthetic shift; experts warn that repeated stress can have notable consequences for both forests and wildlife. Wildlife may be forced to rely on less nutritious food sources if their preferred options become unavailable at crucial times of year. “If typical food sources are not available for animals at specific times of year, this means that they would be forced to eat less desirable and nutritious fallback foods,” stated biologist Bolt, adding that this could negatively impact animal health and population viability.
Compounding the issue of drought are increasing instances of pests and diseases thriving in warmer winters and prolonged hot days, such as outbreaks of emerald ash borer and spongy moth. ”All of those things can compound the stress on the trees,” Hayes noted.
maddalena emphasizes that climate change is intensifying these pressures by increasing the frequency of extreme weather events.”It is, in part, because climate change is worsening some of these extreme weather patterns. It’s making extreme weather more common, and consequently, the natural world has a hard time figuring out what to do with those weather patterns,” he said.Urban areas are particularly vulnerable,as heat is trapped by concrete and asphalt,further stressing street trees.
Experts suggest several steps individuals and communities can take to mitigate the problem. Planting native, drought-tolerant species and expanding naturalized spaces can create more resilient tree canopies. Maddalena recommends utilizing resources like the *Grow Me Instead* guide (
Ultimately, the early arrival of fall colours serves as a critical reminder of the challenges facing Ontario’s forests and the wildlife that depend on them as they adapt to mounting environmental stress.
