[CANUFNET] FW: CANUFNET Digest, Vol 49, Issue 3 Re 1. Re: Urban Tree Species Selection (Fisher, Brian)

Thu Dec 4 17:03:11 EST 2008

Regarding the Native vs. exotic species thread:

In my area, native basically mean Ponderosa pine, Douglas-fir or
cottonwood.  Some of the exotics, however, do quite well and have been
used successfully for a long time, here and elsewhere.  Most of our
successful urban tree species are exotics that have been successfully
planted all over the world in the harshest, driest, worst soils and
inhospitable urban spaces.

Where there is enough space, then by all means let's use the native
species but unfortunately in our urban areas space is a real luxury,
native top soils are completely gone, and trees such as Ponderosa pine
just don't do very well in our downtown; they aren't the greatest
"shade" trees, not to mention planting under power lines or other
difficult spots.  For me it all comes back to the "right tree for the
right space", but there are definitely some advantages to the exotics in
difficult urban settings.

Ian Wilson, RPF, Certified Arborist
City of Kelowna

-----Original Message-----
From: canufnet-bounces at list.web.net
[mailto:canufnet-bounces at list.web.net] On Behalf Of Boysen, Barb (MNR)
Sent: Thursday, December 04, 2008 11:56 AM
To: canufnet at list.web.net
Subject: [CANUFNET] FW: CANUFNET Digest, Vol 49,Issue 3 Re 1. Re: Urban
Tree Species Selection (Fisher, Brian)

Hello,

I can't resist replying re the support of native species being called
dogmatic.  I hope such arguments, surely well meaning if annoying, won't
prevent people from looking at the bigger picture. One species'
significant trouble under climate change impacts shouldn't be a reason
to throw out the whole suite of other choices.

One of the reasons we promote native species is that they are proven
performers on the landscape - they are adapted to the local sites,
climates and communities of species. Also in an urban setting promoting
natives helps the urban island contribute to the gene flow between
adjacent natural areas, rather than act as a barrier, or worse
contribute exotic material.  That material rarely shows itself to be a
problem immediately, usually only after it is now difficult and
expensive to eradicate.  Problems can include poor growth, short life
span, reduced diversity, and increased insect and disease problems;
never mind the really harmful effects if they invade native communities
with the problems of hybridizing and reducing ecological functions.

Where the urban sites themselves are highly disturbed and one could
argue no longer 'native' (or even at all suitable for a tree), the
introduction of exotics is still an experiment - what is the origin of
the clones or populations you are introducing; how different is the
source from your site, will it be long lived, healthy?  

Why not experiment with natives on such sites.  Or restore the sites?

Henry Kock of the University of Guelph used to talk about biologically
appropriate material (BAM).  The idea is to assess what constitutes
biologically appropriate material for any particular situation.  For
example, projects designed to naturalize areas should use seed and/or
propagules of adapted sources of native plants.  An example of
inappropriate material would be the establishment of an exotic that
spreads (or hybridizes with native species) next to a natural area.
There may be cases when the use of an exotic is appropriate - when
native material to meet the planting objective is not yet available.  An
example might be the planting of exotic cultivars that tolerate the
stressful conditions of an urban environment.  

Here's some of his words:  
"BAM - By only growing species that are genetically fit ... i.e. 
-     adapted to the local environment, 
-     of sufficient genetic diversity to avoid the pitfalls of clones,
and 
-     appropriate to the objectives of the planting project
can we ensure the success of our planting efforts and therefore the
benefits that we expect from a healthy forest - rural or urban. Consider
the consequences for the original planting but also for the subsequent
generations- the very long term impact your selections will have. "

Use these principles no matter what species you are considering - but
please consider the natives first.

OR - is the problem really that native species aren't as readily
available yet, in the preferred stock types as the exotic clones and
grafts that tend to be so mass produced?

In that case we can all dare to be part of the solution rather than keep
supporting the problem.

Barb Boysen, Coordinator 
Forest Gene Conservation Association 
Suite 233, 266 Charlotte Street 
Peterborough, ON K9J 2V4 

Tel: (705) 755-3284 
Fax: (705) 755-3292 
Cell: (705) 875-7150 

barb.boysen at ontario.ca

www.fgca.net 

www.ontariosnaturalselections.org 

-----Original Message-----
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[mailto:canufnet-bounces at list.web.net] On Behalf Of
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Sent: December 4, 2008 12:00 PM
To: canufnet at list.web.net
Subject: CANUFNET Digest, Vol 49, Issue 3

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Today's Topics:

   1. Re: Urban Tree Species Selection (Fisher, Brian)
   2. City of Saskatoon Pest Management Supervisor Position
      (McLeod, Geoff (IS - Parks))

----------------------------------------------------------------------

Message: 1
Date: Wed, 3 Dec 2008 09:31:25 -0800
From: "Fisher, Brian" <Brian.Fisher at bchydro.com>
Subject: Re: [CANUFNET] Urban Tree Species Selection
To: <spcushing at yahoo.ca>,     "Canadian Urban Forest Network"
      <canufnet at list.web.net>
Message-ID:

<64B39DDD27287C4DB8A3448A44A8DF250548A097 at EDMBCHMBX2V2.bchydro.adroot.bc
hydro.bc.ca>

Content-Type: text/plain;     charset="us-ascii"

I have a copy of an old manual - (1993) 
Called  STREET TREE FACTSHEETS
Library of Congress Catalog Card Number 92.72203
ISBN 1-883956.00.5
Published by Penn State  - College of Agricultural Sciences with support
of USDA , Penn Dept.of Env. Res (Bureau of Forestry) Pennsylvania
Electric Energy Research Council and Pennsylvania Nurserymen's
Association.

It has very good information on more than 200 species & cultivars and
would merit some updating if someone wanted to pursue that.

I am also finding that at least in our area, there seems to be an
increasing pressure for Native trees from various ad hoc groups. While I
certainly want to avoid true invasives, I think that the approach is
often dogmatic and offers little that is truly helpful. In a Province
where more than half a billion (Yes that's a B) native pines (95% of the
pines in the province) have been killed by Mountain Pine Beetle, I think
we need to be looking at importing new species, not insisting on
natives. Regards,
Brian    

-----Original Message-----
From: canufnet-bounces at list.web.net
[mailto:canufnet-bounces at list.web.net] On Behalf Of Stephen Cushing
Sent: 2008, December 01 4:44 PM
To: Canadian Urban Forest Network
Subject: [CANUFNET] Urban Tree Species Selection

Hello everyone, 

I am doing research on urban tree species selection, based on
environmental stresses.   I am trying to find examples of municipalities
or organizations that have developed, use selection criteria, or follow
a defined process in selecting urban trees. Other than providing lists
of trees to choose from, most municipal websites and documents do not
outline how urban foresters are  selecting the trees they do. 

Any insight would be greatly appreciated. 

Cheers,
Stephen Cushing
MLA Candidate 2009.   