Street Trees

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Neil Carleton 2 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.

October 12 2012 Fall Leaves
Beneath the beauty of fall leaves is a remarkable chemical transformation.  As the food factories of a tree change colour before the arrival of winter, nutrients are transported to the roots for reuse in the spring.

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.

Almonte Street Trees 2 November 26 2014 - Copy
The urban landscape in the heart of Almonte is a tough growing environment that’s far removed from a tree’s natural growing conditions.  Space is usually tight in downtown environments.  In towns and cities across the province, newly planted street trees have often been shoe-horned between private building frontages and curbs.  This view of lower Mill Street is looking east in front of Vamos, Almonte’s outdoors clothes shop.
Street Trees Lower Mill Street circa 1910
Almonte was incorporated as a village in 1870, and as a town in 1881 with a population of about 2700.  Downtown trees are a recent addition to the urban landscape of our community.  In this view of lower Mill Street, the young pedestrians on the right, following the band, are located along the stretch of sidewalk where trees would be planted during the time of their great or great great grandchildren.  Photo courtesy of the Michael Dunn Digital Archive.

 

Almonte Street Trees 1 November 26 2014 - Copy
This location on lower Mill Street, before the Heirloom Café, is a welcome shady spot for passersby on a hot summer day.  Finding sufficient nutrients and water is just one of many challenges for street trees.

 

Almonte Street Trees 3 November 26 2014 - Copy
A few sidewalk trees along Mill Street are caged for protection from potential physical damage.  While others have a pair of metal guard posts, this maple warranted a four corner arrangement.  It was planted in front of the Utramar gas station (now a vacant lot and brownfield site) when there was plenty of incoming and outgoing traffic.  The burgundy leaves of its summer canopy are a colorful contrast to the green foliage of the neighbourhood.  Maple trees with mature red leaves are alien species, including the Norway variety known as ‘Crimson King’ with leaves that are deep purple or almost black. They’re known for the intensity of their leaf colour, fast growth, and dense shade.
Almonte Street Trees 4 November 26 2014 - Copy
Next to the Bank of Montreal, along Brae Street, are two of our downtown’s larger street trees.

 

Street Trees New Bank Of Montreal
It’s been a long time since the slope at the current corner of Mill and Brae Streets was naturally forested.  The trees of the downtown area were cleared for lumber and fire wood, and for building lots.  Almonte was a thriving commercial centre when the Bank of Montreal moved from Bridge Street, the current Legion building, to its downtown location, built in 1906.  Photo courtesy of the Michael Dunn Digital Archive.
Almonte Street Trees 5 November 26 2014
Significant heaving has occurred around the base at one of the Brae Street trees next to the Bank of Montreal.  When street trees don’t have an adequate volume of soil for root growth, there can be pavement failure as well when the roots expand with age.
Almonte Street Trees 6 November 26 2014 - Copy
The street tree under the greatest stress in downtown Almonte is growing in Centennial Square, at the intersection of Mill Street with Little Bridge Street.  The symptoms of poor health include sparse foliage this year, along with a significant trunk wound.
Street Trees Post Office
What a different streetscape it was before trees were planted in downtown Almonte.  Photo courtesy of the Michael Dunn Digital Archive.

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.
Street Trees Topsoil
To support the growth of a healthy street tree, a minimum of 1.5 – 2 cubic feet of loam-based soil is needed for every expected square foot of canopy.  Photo: Wikimedia commons, the free media repository

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:

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

Street Trees Google Street View

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.