[CANUFNET] Trees and boulevards

Mon Oct 4 12:26:04 EDT 2021

Hi Ian,
We see a lot of different standards among communities with and without boulevard planting strips and the outcomes really vary. In new subdivision construction, the removal of topsoil affects long-term tree growth potential on both the private and public realm side. The road construction standards are focused on compacting soil to remove air voids and making it more difficult for water to flow through and the drainage standards are focused on taking the water away from the site quickly and efficiently. Unfortunately, our objectives for creating site conditions to grow trees are often at odds with the engineers' standards.

To add to the debate, I don't think there's a universally observable performance outcome for each approach - other than garbage soil in, garbage tree out. Either approach can succeed or fail so soil standards and enforcement are critical. The monolithic sidewalk may be simpler to implement at the construction stage but there are trade-offs. I think in the end it's a matter of the character you're going for.
[cid:image003.png at 01D7B901.D7FCE520]
Winnipeg blvd strip and monolithic in new developments
[A road with trees on the side  Description automatically generated with low confidence][A picture containing text, sky, outdoor, road  Description automatically generated]
Calgary boulevard strip and monolithic
[A street with cars on it  Description automatically generated with low confidence][A road with cars on it and trees on the side  Description automatically generated with medium confidence]

Trevor Thistle's observation of older neighbourhoods ring true for me. The soil wasn't removed in older parts of cities and even with a lot of compaction over time and loss of pervious cover, trees can thrive if the underlying soil structure is suitable (see the image spread below of plane trees from 1888 to 1945 to 2013). If your trees are growing well, do everything you can to prevent full road renewal!

[IGA_11_1_2013_17_3_20_419][A picture containing text, tree, outdoor, road  Description automatically generated][A street with trees and buildings  Description automatically generated with low confidence]

Amelia Needoba | Principal | PMP, ISA Cert. Arb (she/her)
3559 Commercial Street | Vancouver | V5N 4E8
Diamond Head Consulting<http://www.diamondheadconsulting.com/> P 604.733.4886<tel:604.733.4886> ext. 233 F 604.733.4879<tel:604.733.4879>

From: CANUFNET <canufnet-bounces at list.web.net<mailto:canufnet-bounces at list.web.net>> On Behalf Of Ian Wilson via CANUFNET
Sent: September 28, 2021 12:59 PM
To: 'canufnet at list.web.net' <canufnet at list.web.net<mailto:canufnet at list.web.net>>
Cc: Ian Wilson <IWilson at kelowna.ca<mailto:IWilson at kelowna.ca>>
Subject: [CANUFNET] Trees and boulevards

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All, we are having a bit of an internal debate about standards for local/residential roads and boulevards.  My observation is that trees that are planted in a boulevard behind a monolithic sidewalk (sidewalk up against the curb and planting area next to the property) generally do better. They have access to more soil volume in the front yard, they get more water and the boulevard is tidier since the homeowner treats it like part of their yard. Also fewer issues with roots lifting sidewalks. Some of our staff prefer the separated treed boulevard, for various reasons. Note, I'm not talking about busier roads where the trees in boulevards help to form a barrier from traffic.

We don't have a lot of good examples here that directly show a comparison. Does anybody have some photos that might show the performance of trees on one side of the road in a separated boulevard, vs. trees on the other side behind the sidewalk?

Below is an example that doesn't exactly show this, but it does show the value of soil volume, with the trees on the left side being able to access the lawn area behind the sidewalk, vs. the trees in "coffins" on the right. These are lindens planted at the same time.

[cid:image005.jpg at 01D7B6AD.4ECA30B0]

Ian Wilson
Infrastructure Operations Manager | City of Kelowna
250-469-8842 | iwilson at kelowna.ca<mailto:iwilson at kelowna.ca>
Submit a request for service on the go | kelowna.ca<https://can01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fkelowna.ca%2F&data=04%7C01%7Camelia%40diamondheadconsulting.com%7C1776b1418e8e425cb95408d9835cc915%7C36c9e1fa9ad14c25997b6ddc542a83f3%7C0%7C0%7C637685256802921352%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=8Jud%2B5r7c2atbaMmcCDwFpiqzFn8EAo0R4EOumzwawk%3D&reserved=0>
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