- The densely canopied portion of the ravine just south of the small steps leading up to Weybourne Crescent
- Photo: © Shaun Merritt
The natural area to the south, beyond the wood stairs, is densely-shaded by a thick canopy of Norway maples (Acer platanoides). At first glance, many people may consider this to be a healthy native forest, but the sad reality is that the vast majority of the trees and understorey plants that blanket this slope are non-native species. Instead of boasting a variety of small bushes and plants, the ground of this ravine is primarily covered with an invasive exotic plant species called garlic mustard (Alliaria petiolata). There is limited biodiversity, which means this forested area, and many others like it in Toronto, will be less likely to withstand pressures from climate change or pests.
Norway Maples have found their way into our ravine system due to their popularity in previous generations as street trees. They produce many seeds, which can travel great distances and often end up in our ravines, one of the few places where remnants of the original forest still exist. One seeded, Norway maples grow quickly, their large leaves starving the native plants beneath them of sunlight and water. As ravines such as this one lose their diversity of plant life, the birds, animals and insects that relied on them move on in search of new sources of food and shelter.
Riding our natural areas of damaging exotic invasive plants is an extremely difficult task that the City of Toronto, Urban Forestry staff are working on with the help of volunteers throughout the city. There are also many local community groups that work in partnership with City employees to control exotic invasive species and restore Toronto’s ravines to the stunning ribbons of green they are. But ultimately, one of the easiest, and most effiective, things we can do to protect our ravines is never plant exotic invasive species such as Norway maples in our yards.
- Next stop: From fossil to front yard
- Previous stop: Have park, will travel
- Return to map of: Lawrence Park
Funding for the program is generously provided by:
