[CANUFNET] Trees and boulevards

Julian Dunster jd at dunster.ca
Wed Oct 6 14:37:18 EDT 2021


Storing topsoil in lifts is very unlikely to take place, and it is far 
from clear that it would work effectively even if it was done. The bulk 
handling of soils requires heavy machinery and soils are a complex 
structure. In the late 70's I looked at conservation efforts in the UK 
to carefully dig up entire habitats in large deep chunks of soil and 
carefully replace them in a new location, in an effort to conserve the 
grassland ecosystem under threat. It was extremely time consuming, very 
expensive, and my recollection was that ultimately, it had very variable 
success because the soil evolution is tied to the micro site conditions.

For street trees the main issues will be the volume available for root 
growth, soil quality, quantity and the amount of care taken when 
installing the soil and the tree, plus, the condition of adjacent soil 
profiles. All of this is well known and well proven by Jim Urban's work. 
Nothing new but the knowledge is seldom applied by designers, engineers, 
and their cohort so we get crappy designs and equally crappy results. If 
we can one day get the design professions to do better we could solve 
some of the street tree issues.

On Behalf of Dunster and Associates Environmental Consultants Ltd.


Dr. Julian A Dunster R.P.F., R.P.P.., M.C.I.P., ISA Certified Arborist,
ASCA Registered Consulting Arborist # 378,
ISA Tree Risk Assessment Qualified
Honourary Life Member ISA + PNWISA

North American distributor for Rinntech
www.dunster.ca
www.treelaw.info
www.rinntech.info

On Tue/10/5/2021 10:55 AM, pwassenaer1022--- via CANUFNET wrote:
>
> Not in my experience but perhaps others on this list could indicate if 
> they have seen it in their jurisdictions.
>
> Philip
>
> *Philip van Wassenaer, B.SC., MFC*
>
> Urban Forest Innovations Inc.
>
> 1331 Northaven Drive
>
> Mississauga ON L5G 4E8
>
> Tel:  (905) 274-1022
>
> Cell: (647) 221-3046
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> Fax: (905) 274-2170
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>
> *From:*CANUFNET <canufnet-bounces at list.web.net> *On Behalf Of *Naomi 
> Zurcher via CANUFNET
> *Sent:* October 5, 2021 2:31 AM
> *To:* Canadian Urban Forest Network <canufnet at list.web.net>
> *Cc:* Naomi Zurcher <treerap at sprintmail.com>
> *Subject:* Re: [CANUFNET] Trees and boulevards
>
> Philip - as I had indicated, I thought this should at least be 
> possible with Public Infrastructure projects.
>
> Is it being required for projects on public lands?
>
>
>
>     On Oct 4, 2021, at 10:37 AM, pwassenaer1022--- via CANUFNET
>     <canufnet at list.web.net> wrote:
>
>     Ha ha ha….entirely possible but who will impose that and enforce
>     it on the development community?
>
>     In my experience the development community has an inordinate
>     amount of sway over municipalities and things related to
>     development. Until that changes, these things will remain
>     “possible” but will not be implemented…
>
>     Philip
>
>     *From:*CANUFNET <canufnet-bounces at list.web.net>*On Behalf Of*Naomi
>     Zurcher via CANUFNET
>     *Sent:*October 4, 2021 10:08 AM
>     *To:*Canadian Urban Forest Network <canufnet at list.web.net>
>     *Cc:*Naomi Zurcher <treerap at sprintmail.com>
>     *Subject:*Re: [CANUFNET] Trees and boulevards
>
>     Why can’t municipalities require that any and all construction
>     must remove existing topsoil in lifts and thoughtfully store that
>     topsoil for re-installation on the same site. This should be
>     entirely possible at least on public infrastructure projects.
>
>
>
>
>         On Oct 1, 2021, at 1:34 PM, Oliver Reichl via CANUFNET
>         <canufnet at list.web.net> wrote:
>
>         “Nowadays developers remove all of the precious topsoil from
>         the land before building a new subdivision, then bring back
>         enough topsoil to support the new sod.“
>
>
>
>
>         That’s been standard practice in the GTA for decades. Can a
>         municipality regulate soil volumes?
>
>         On Fri, Oct 1, 2021 at 11:12 AM Trevor Thistle via CANUFNET
>         <canufnet at list.web.net> wrote:
>
>             Hi Ian,
>
>             Here in Edmonton I have been working almost
>             exclusively with tree conservation during Neighborhood
>             Renewal (NR) for 13 years. NR is the process of
>             reconstructing all sidewalks, curbs and streets in a
>             neighborhood, as well as adding missing infrastructure.
>
>             In our oldest neighborhoods I feel that trees growing in
>             boulevards with separate sidewalks (curb on one side,
>             sidewalk on the other side of the tree) have not really
>             been impacted by the perceived restricted growing area,
>             with the exception of roots literally engulfing curbs or
>             overlapping sidewalks. I believe that the reason for this
>             is that the construction standards that were in place
>             decades ago (between neighborhood establishment and the
>             time the sidewalk was last replaced) allowed for the
>             construction of sidewalks on top of organic soil. So, in
>             most cases, the trees had little challenge accessing soil
>             beyond the boulevard.
>
>             However, new construction standards include a gravel base
>             and mechanical compaction under sidewalks. Also,
>             greenfield construction is not what it used to be.
>             Nowadays developers remove all of the
>             precious topsoil from the land before building a new
>             subdivision, then bring back enough topsoil to support the
>             new sod. In these cases, regardless of the sidewalk design
>             (mono or seperate) the trees do not have enough soil
>             volume to support them. We do amend soil volumes with
>             trenches in separate boulevards, but these are trenches in
>             clay with still inadequate soil volumes. So my point is,
>             depending on construction practices and standards, the
>             configuration of the sidewalks in relation to the trees
>             may have less impact on soil growing space than we think.
>
>             but I would agree that trees in a more free to grow state,
>             with little or no barriers to quality soil will outperform
>             a tree in restricted growing space, and there will be
>             fewer infrastructure / tree conflicts. This means that we
>             will minimize tree related damages to infrastructure and
>             construction related damages to trees in order to maintain
>             that infrastructure.
>
>             *Trevor Thistle****Bsc. Forestry*
>
>             *Urban Forester | PR-4760AM | Tree Risk Assessment Qualified*
>
>             OPEN SPACE OPERATIONS
>
>             CITY OPERATIONS | PARKS AND ROADS SERVICES
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>
>             City of Edmonton
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>
>             12830 58 Street NW
>             <https://www.google.com/maps/search/City+of+Edmonton%C2%A0+12830+58+Street+NW?entry=gmail&source=g>
>
>             On Wed, Sep 29, 2021 at 9:21 AM Ian Wilson via CANUFNET
>             <canufnet at list.web.net> wrote:
>
>                 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.
>
>                 *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
>                 <http://kelowna.ca/>
>
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>                 traditional, ancestral, unceded territory of the
>                 syilx/Okanagan people//./
>
>
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>         --
>
>         Oliver K. Reichl, B.E.S.(Hons)
>         -----------
>         Sent from my mobile phone.
>
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