Thank you for your response! A couple follow up questions…
Why might we want to steer away from a large shade tree on our small lot? Just the appearance in proportion to our narrow house? Or impact of the root system on our neighbours? Or other reason? There are many large maples in our part of the city…
Is the serviceberry vulnerable to pests…one site I found suggests it is. What about road salt?
Would a redbud be suitable in city conditions?
Of course you can plant a large tree, it will provide shade and cooling for many years. However, in your criteria list you’d mentioned not blocking light and views from your window. If you have a large tree with a wide canopy, your views would strictly be the tree, and light would inevitably be blocked. So, I suggested the smaller trees for your smaller yard.
As well, in the old city, impact on drainage is an issue for many. If your drains have been changed from the terracotta, and are now PVC, it’s less of a problem with roots seeking moisture.
As for proportion, it is true, a large, mature tree is sometimes odd on a small lot. Also, these trees will essentially dominate the soil, and little will eventually be able to grow on the front garden. Tree roots are in the first 15cm of soil, and they will take up all the moisture.
As well, you had a concern about falling branches on your property. As trees mature, their branching structure need professional care to reduce the potential for broken branches – the July and December 2013 storms were proof of that. If it’s a city tree, on city property, the city is responsible for the care. However, it is your responsibility to ask for the care from the city. At this point, emergency care is what’s happening now. If the tree is on your property, however, you are responsible for the cost of professional care and maintenance from a licensed arborist.
The serviceberry (Amelanchier sp.) is a native tree and can withstand our climate conditions. As the tree is in your yard and not on a boulevard, road salt is not really a concern. In my experience, they suffer from few pests or disease. For a small yard, the grey, smooth bark, flowers, berries and dynamic fall colour is a great focal point. These trees are easily underplanted by perennials and ornamental shrubs and grasses, to add texture and colour to the yard.
Eastern Redbud (Cercis canadensis) also is native to the southern most parts of Ontario. It is an understorey tree or shrub in native habitats, so can withstand some shade. The Brickworks have them planted among white pine (Pinus strobus) and in spring, the magenta, pea-shaped flowers contrast dramatically with the light green pine needles. From a distance, it’s like a haze of pink. The Toronto Botanical Gardens also have redbud, including some of the cultivars.
Truly a gorgeous tree in spring, and afterwards, the heart shaped leaves are attractive, and they turn yellow in the fall. They have a wide, almost oval canopy. Their fruit is a long seed pod. Like the serviceberry, this tree can be underplanted easily.
Even so, redbud are a brittle tree, and are best planted as a clump, rather than a standard trunk. They should also be planted where wind is minimal, as the forked branches tend to split. The leaves are eaten by some caterpillars, and around mid-summer, the redbud in my yard sports round chunks cut from the leaves by leaf-cutter bees. That is harmless to the plant, but may be considered unsightly to some.
For more information: http://canadiantreetours.org/species-pages/Eastern_redbud.html
Hope this helps with your decision.