1) Define the space of the street.
This particularly applies to streets that are too wide for the height of the buildings, streets with holes in the street wall, or suburban streets where buildings are too far apart to contain the space of the street. Mature trees provide canopy.
2) Define the pedestrian space.
3) Calm traffic and protect the pedestrian from cars.
4) Filter the sunlight..
5) Bring order to the street.
6) Visually soften the streetscape.
7) Introduce the beauty and life of nature.
I think this list sums up the roles of urban street trees pretty nicely. Is it brief? Definitely. Could we make a list of the roles of urban street trees that is twenty, thirty, forty items long? I imagine so (note to self…).
Reading Massengale’s list made me think about that list, and how long it might be. The longest list I think I’ve read yet is 22 items long and was written by Dan Burden, an Urban Designer at Glatting Jackson. Given all of the benefits, some of which represent very real financial, ecological, and/or psychological value, it seems clear that street trees should not be an added perk for people living on particular blocks who — and we’ve got a chicken/egg thing going on here — likely pay higher rent and mortgages as a result. The successful integration of street trees in to our cities and towns is the responsibility and moral imperative of developers, municipalities, and designers. With a very few exceptions, it seems to me that streets should have trees on them without exception.
Image of Augusta, GA from beardenb