
The trees covering this patio are Norway maples (Acer platinoides), which are commonly planted as street trees across North America. They are a welcome addition because they provide cool shade for those seated at the tables who would otherwise be sipping quickly warming beers. Nevertheless, Norway maples can be very damaging. They have a habit of getting into Toronto’s ravines and taking over the lasts remnants of the area’s native forest, crowding out undergrowth plants and other tree species.
Despite being an invasive species, these trees aren’t immune to the stress of urban conditions. These particular Norway maples are small and not growing well. If they were in a location with more open soil, they could be twice as tall. One reason that these trees are growing at all is because the laid stone of the patio allows some water to filter down into the soil to reach the trees’ tender roots.