Behalf Of James Parton
Sent: Wednesday, January 23, 2008 1:02 AM
Subject: [ENTS] Re: Pittsburgh Cutting Trees
I don't think I have ever seen a Norway Maple around here in WNC. I
wonder if Will has. If their leaves are larger than our native
Maple than they really are big.
Judging by the name I figured it was an invasive tree, like
Altissima ( Paradise Tree or Tree of Heaven ).
== 4 of 12 ==
Date: Tues, Jan 22 2008 10:58 am
From: Carolyn Summers
Good question. Norway maples were Frederick Law Olmsted's biggest,
lasting mistake. He designed Central Park in NYC back in the 1800s
reasons no one fully understands, he decided to plant gazillion
maples instead of our own gorgeous sugar maples. (I like this story
it makes folks feel better to realize that even the best, most
experts really blow it occasionally.) This is no mere aesthetic
because 100 + years later, Norway maples have naturalized all over
metropolitan NY and are threatening New England and parts south.
So why is that a problem? Norway maples evolved in Norway, a land
greatly reduced sun compared to the NYC latitiude. Thus they evolved
leaf out extra early, with extra-large, thick leaves. They also
their leaves longer in the fall. They are also extremely prolific in
of seeds. They have no insect predators; our insects can't tolerate
leaf chemistry. The net result is that they are quite literally
outcompeting sugar maples, oaks and many other native trees and
whole forests. Nothing can grow underneath their dense dark shade.
ephemerals on the native forest ground layer can bloom and set seed
complete their entire life cycle in the time it takes most eastern
trees to fully leaf out. That can't happen under Norway maples. To
insult to injury, scientists supect that Norway maples are
that is, their roots exude toxic chemicals into the soil to further
The Nature Conservancy has mounted an effort to arrest the spread,
nurseries in NY still sell them! It drives me crazy. If you see one,
it before it spreads.
I have a series of photographs that I use in my presentations that
various stages of leaves opening in the spring and also fully leafed
Norway maples invading leafless forests in spring and fall. The
really tell the story.
63 Ferndale Drive
Hastings-on-Hudson, NY 10706
> From: James Parton <firstname.lastname@example.org>
> Reply-To: <email@example.com>
> Date: Tue, 22 Jan 2008 10:14:50 -0800 (PST)
> To: ENTSTrees <firstname.lastname@example.org>
> Subject: [ENTS] Re: Pittsburgh Cutting Trees
> Why Norway Maples?
> On Jan 11, 5:12 pm, Carolyn Summers <csumm...@springmail.com>
>> Weıve had this problem, or a similar one, with Con Edison
being urged on by
>> the Public Service Commission. Trees next to utility wires
are taken down
>> in advance of storms as a way of preventing power outages
that go on for
>> days after storms. We actually had a tornado in Westchester
2 years ago and
>> I think thatıs when concerns mounted. Iım always happy to
see Norway maples
>> cut down, but when they go after the old oaks...... My
advice to Pittsburgh
>> is to try to stop it, but settle for a publicly funded
>> who will represent homeowners and monitor the cityıs
>> what we did and the outcome was not too bad.
== 6 of 12 ==
Date: Tues, Jan 22 2008 11:39 am
From: "William Morse"
I was in Narvik and Tromso, Norway a few years back, ~400 miles
of the arctic circle, and the only deciduous tree I recognized on
city streets was Acer platanoides. An amazingly hardy species in its
own right. Travis
== 7 of 12 ==
Date: Tues, Jan 22 2008 11:58 am
From: "Lee E. Frelich"
Norway maple is hardy when it comes to dealing with short cool
in Norway), but not cold winters (as in Minnesota). In southern MN,
maple is a stunted tree with many frost cracks on its trunk, which
nevertheless still manages to invade native forests. I don't believe
survive in northern MN, with -40 winter temperatures, at least for
southern MN, Even as a crooked, cracked, stunted tower of tattered
still shades out seedlings of other tree species, and its leaf
favors invasion of European earthworms (some species of which are
detritivores that consume dead leaf litter) that cause further
== 10 of 12 ==
Date: Tues, Jan 22 2008 12:43 pm
From: "William Morse"
I was there in January and February and the temps were 40 to 60
zero and the maples were all 20-40 feet tall. A bit smaller than
in the states, but I can't say that they were stunted. I don't
remember seeing any frost cracks either..... maybe a local
Norway maples have a wide distribution and depending on the
evolutionary history of the stock, less cold hardy species may have
been the progeny of the trees mentioned in MN. I would guess that it
is genetic variation from warmer-evolved parent material that makes
them less suited to MN winters. It would be nice if less
adaptive/maladaptive traits could be introduced into weedy
and create a population bottleneck for invasives. Travis
== 11 of 12 ==
Date: Tues, Jan 22 2008 1:23 pm
From: "Lee E. Frelich"
You are right--our Norway maple in MN must have originated from
further south. It sure doesn't tolerate our winters in MN very well.
The short heights in Norway are probably more a function of short
than winter minimum temperature.
TOPIC: Pittsburgh Cutting Trees
== 1 of 6 ==
Date: Wed, Jan 23 2008 5:48 am
From: "Will Blozan"
Unfortunately, Norway maples are all too common here in WNC
big cities like Asheville and Hendersonville. Fortunately, a wilt
ruthlessly ravaging them and gradually eliminating them from the
They can be invasive but not as much down here as I have seen around
The NC state record is on Montford Avenue in AVL and is actually
impressive. One of my clients had one with a crown spread in one
of 92' but it think verticillium wilt has gotten to it now.
I won't miss them.