[CANUFNET] Healthy tree definition

Thu Jan 28 00:45:43 EST 2010

With regard to Travis' comments, it seems to me that this wording leaves it
completely open to whatever  subjective interpretation your inspectors may
have on any particular day, with no recourse whatsoever for the contractors
or nurseries that have their trees rejected.  You are basically saying that
a tree must conform to your standards, whatever they may be, right or wrong.

In point of fact, trees are not normally high headed, and must be pruned
that way in the nursery. Such pruning is clearly detrimental to the health
of the tree, and in most cases, stunts the growth, reduces taper and trunk
strength, and invites disease and poor compartmentalization, which can lead
to trunk cracks, sunscald and several other defects that I can think of.
This is all well researched and documented in Alex Shigo's book 'A New Tree
Biology" 1989 and in "Modern Arboriculture." 1990. Other researchers such as
Gilman have since written excellent books on the topic of pruning and
pruning trees for urban areas in the nursery, which have been universally
accepted by most of the rest of North America and the world. 

And what of trees that do not normally have a central leader in the Edmonton
area? Trees like Green Ash, Mayday, Schubert, Amur Cherry  and Ornamental
Crabapples very rarely possess a "single dominant, well developed leader." I
can only imagine that very few otherwise healthy trees of these varieties
survive your inspection process!

Even if any particular Urban Forestry department actually knew what a
"healthy tree" was and could specify this in a way that was "not open to
interpretation", there is no guarantee that picking a tree simply on the
basis of "good" form will guarantee future good health, especially in a
place where trees are notoriously difficult to grow, such as the Western
Prairies. Planting methods are the single biggest factor influencing the
success of a tree. And while you are  perfectly right not to accept a tree
with obvious signs of abuse such as scrapes and broken branches, we continue
to plant the healthiest of trees in the worst of places and blame the tree
when it dies. Trees need room to grow both above and below the ground to
sustain themselves, and usually have neither in most Urban Areas in the
world today.

Fixating on a tree's form, especially when the form is entirely unnatural to
the species or variety,  certainly should never be considered the only
attribute of potential  good health!

We obviously need to rethink the whole notion of "tree health" when Urban
Areas are still in the design process.  I believe it is possible to shape
cities to conform to nature, but nature cannot be retrofitted to fit our
cities, if our cities are to be sustainable.

Food for thought.

ForTreeslogocolour

Gerard Fournier

Board Certified Master Arborist #PR-0130BT

Tree Canada Community Advisor-Southern Alberta

President

For Trees Company Ltd.

1-877-390-TREE (Alberta toll-free)

 <http://www.fortrees.ca/> http://www.fortrees.ca

From: canufnet-bounces at list.web.net [mailto:canufnet-bounces at list.web.net]
On Behalf Of Travis Kennedy
Sent: January-27-10 4:17 PM
To: 'Canadian Urban Forest Network'
Subject: Re: [CANUFNET] Healthy tree definition

Our Design and Construction standards touch briefly on "healthy" but add a
number of other quality measurements to reinforce our intent:

Refer to section 02930 2.2 and 2.3  in Volume
<http://www.edmonton.ca/city_government/documents/PermitsLicences/D_and_C_la
ndscapsng.pdf>  5:  City of Edmonton Design and Construction Standards.

A design review comment that we like to make on submitted drawings from
developers usually contains some or all of the wording below (this
particular case is in reference to deciduous blvd. material):

"All trees to be high headed and exhibit a full and uniform crown, with a
single dominant, well developed leader. Trees with broken or damaged or
missing leaders will not be accepted. All plant material must conform to the
City of Edmonton Design and Construction Standards." 

This comment in combination with the standard helps prevent confusion about
what is and isn't acceptable during our CCC / FAC inspection process.

Regards, 

Travis Kennedy, BSc, AIT 
River Valley, Forestry and Environmental Services 
12304 - 107 Street 
Edmonton, Alberta 
T5J 2R7 
p 780 496 4954 

-----Original Message-----
From: canufnet-bounces at list.web.net [mailto:canufnet-bounces at list.web.net]
On Behalf Of Kowalyk, Bohdan (MNR)
Sent: Monday, January 25, 2010 7:05 PM
To: Canadian Urban Forest Network
Subject: Re: [CANUFNET] Healthy tree definition

There are various tree classification systems depending on intent.  For some
purposes, it may be appropriate to require confirmation by a qualified
person, subject to an authority's approval, that a healthy tree is not
likely to degrade in health and functional attributes for at least the next
15 years.

Bohdan

  _____  

From: canufnet-bounces at list.web.net [mailto:canufnet-bounces at list.web.net]
On Behalf Of SVescio at thunderbay.ca
Sent: Monday, January 25, 2010 1:02 PM
To: canufnet at list.web.net
Subject: [CANUFNET] (no subject)

Hello out there, 
Is there an accepted or standard definition for the term "healthy tree"?  We
would like to revise the wording for acceptable condition of trees at final
inspection and do not want the health of a tree open to general
interpretation.  Thanks. 

Shelley Vescio RPF 
City of Thunder Bay 
(807) 625-2473 
(807) 625-3258 (fax) 

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