by Neil Carleton
When I’m on foot, I look for trees that arch over sidewalks and pathways that I can stroll under. The closer the leaves are to my hat the better.
The urban environments we live and work in have a significant effect on us. We certainly feel better in the company of trees. The increased benefits of trees on human behavior and health are well known. A street tree is a welcome oasis in an urban setting of concrete, pavement, brick, and stone.
While walking downtown in Almonte last month, I was thinking about the renewal / upgrade of Mill Street, and Little Bridge Street, that will be under consideration in the next few years. There’s much to plan for before the project moves ahead. This includes traffic + transportation and parking + water distribution + wastewater and drainage collection + street lighting + streetscaping + geotechnical and environmental issues + access to utilities. Public / landowner consultation will be an important part of the process, and a design charette has been suggested as one way to facilitate community input.
Here’s hoping that street trees are a component of the design / planning process. This would be a great opportunity as well to develop best practices for the planting and maintenance of new trees, and the possible relocation / replanting / remediation of existing street trees.
Each of Almonte’s street trees has a survival story to tell. A walk along Mill Street is a good way to meet them.
Whether they’re planted on the main street of a small town or along a city thoroughfare, street trees are subject to common stresses, each affecting their health and growing success. This list, compiled for the survival strategy of street trees in Toronto, is just as applicable to Mill Street in Almonte. http://www.cleanairpartnership.org/files/StreetTrees%20Final.pdf
Soil Quality
- Soil in urban environments is frequently compacted due to weight and pressure from sidewalks, which can act as a barrier to healthy root development.
- Soils along sidewalks where trees are planted are often nutrient poor.
Soil Quantity
- Each tree requires 1.5 to 2 cubic feet of soil for every square foot of crown projection. This is seldom available for street trees.
Water
- Street trees seldom receive enough water.
- Soils in urban environments are often unable to drain properly.
- Contractors who plant street trees must water and maintain the trees for two years; however, in an urban environment, trees require a longer period of care.
Salt from Roadways and Sidewalks
- Street trees often come into contact with road salt which is toxic to trees.
Infrastructure Replacement
- Maintenance activities to repair or replace sewers, underground electrical or gas lines, sidewalks and streets can damage tree roots and canopy.
Extreme Heat
- Nearby pavement and other hard surfaces reflect heat, which causes trees to lose water, depleting already limited supplies.
Nowadays, where tree pits can’t be made large enough for proper tree growth, or there’s a need for paving, the paving units can be supported with a bearing product, such as a silva cell. This is a modular system that holds unlimited amounts of lightly compacted soil while supporting traffic loads beneath paving. The volume of healthy soil housed within silva cells allows for the growth of large street trees. Hooray!
Wondering what such a system looks like, I tracked down:
- photos of an August 2012 installation for the greening of the St. Clement schoolyard in Montreal http://www.deeproot.com/blog/blog-entries/the-greening-of-st-clement-schoolyardcase-study-montreal-quebec ;
- a 2:48 time lapse video of an installation at the Haas School of Business at UC-Berkeley in California which was filmed over several weeks during the winter of 2013 http://www.deeproot.com/blog/blog-entries/time-lapse-video-of-a-silva-cell-installation .
The posting of these links is not intended as an endorsement of the silva cell product for which I have no first hand experience, and no technical expertise. They’re meant to illustrate one creative way of approaching the planting of trees in an urban environment.
To urban planners / designers, the science of street tree placement is well known. That’s important because street trees are highly valued by people living, working, and shopping in urban places. Street trees provide many benefits to their urban communities. Here’s a link to a listing of 22 benefits with inspiring photo examples. http://www.michigan.gov/documents/dnr/22_benefits_208084_7.pdf
It’s easy during the winter months to see our downtown street trees with their summer leaves on. A tour by Google Street View makes it possible. This on-line technology displays streetscape panoramas of stitched images that were photographed from equipment mounted on a car roof.
For a tour of Mill Street in the summer, the first step is to head for Google Maps at https://maps.google.ca/. In the box at the top left, type in ‘Almonte Mississippi Mills’ to access a map. Over at the bottom right, click 3 times on the + symbol to zoom in. Right click and hold, then move the map around to see the downtown area. Click on the fork and knife symbol for the Mill Street Crepe Company, then, back up at the top left, click on the Street View image. Use the compass symbol over on the lower left to rotate the view. When you’re ready to head up Mill Street, move the cursor ahead and right click. Zoooom.
Do you have a notable or favourite tree? Readers are invited to submit their nominations for an honor roll of trees in our area that could be featured in future articles. You can contact me at 613-256-2018, <ve3nce@gmail.ca>, or Neil Carleton, 3 Argyle Street, P.O. Box 1644, Almonte, Ontario, K0A 1A0. I look forward to hearing from you.
My volunteer columns started in March 2010, as print features, to support the tree planting and tree awareness initiatives of the Mississippi Mills Beautification Committee. The contact for the Tree Committee (Beautification Committee subcommittee) is Ron Ayling, 613-804-4617. In Carleton Place, the contact for the Urban Forest / River Corridor Advisory Committee is Jim McCready, 613-257-5853.
Until the next column, you’ll find me looking for and hanging out with shady characters.
