The trees in question have triangular clusters of small white flowers that bloom around this time of year, in this area (Montreal/Eastern-Central Canada, probably in surrounding areas as well.) Their leaves are what most people picture an ordinary leaf shape to be. The flowers smell a bit like lilacs. Here is a picture.
These trees are so common that I’m sure the answer to this question is easy, but I wasn’t quite sure what to google to look for the answer, so I thought I’d ask here.
It could be a Linden. The shape of the leaves, the generally conical shape of the older tree, and the flowers all look right. Ours is in bloom here in Michigan right now, and does smell like lilacs.
Ours is a little leaf Linden, but there are other varieties as well. Do the flowers have a lighter green “leaf” (bract) associated with them?
The reason I am going with Syringa reticulata is because although blurry, one can make out the heart shaped leaves, also a hint of the opposite leaf pattern. Although the panicles are a bit spotty, arrays not full across the tree, take a look at these images of Syringa reticulata, see what you think…
I have a Syringa reticulata that I purchased bare root from mail order catalog 10yrs ago, has already reached a height of 12ft with equal spread - only mine has purple flowers on it.