Subject: Re: re. Should I cut my elms
From: wtmorgan@pilot.msu.edu (Bill Morgan)
Organization: Michigan State University
Date: Wed, 08 Apr 1998 21:58:40 -0400
Message-ID: <MOD$980408.5905@rec.gardens.ecosystems>
References: <MOD$980408.29240@rec.gardens.ecosystems>


In article <MOD$980408.29240@rec.gardens.ecosystems>, "Bill Robinson"
wrote:

> What I should have said was that the elm bark beetles are
> attracted to the old, neglected, and damaged trees which they
> use as breeding sites and they are attracted to younger and
> healthy trees as sites for feeding. The feeding sites on the young
> & healthy trees can become infected. Young and healthy elms do
> have better resistance to the pathogen but it is sometimes
> inadequate. Trees stressed by drought, etc. don't have much of a future.
>
>
> The organism that causes Dutch elm disease is caused by the
> fungus, Ceratocystis ulmi which becomes a threat to the tree once
> it gets into the water conducting tissue of the tree. The pathogen
> produces a gum that restricts the passage of water and nutrients.
>
> See the Michigan State University Extension publication on Dutch
> elm disease @ >http://www.msue.msu.edu/jackson/hort/dutchelm.htm
>

BTW, the fungus can also be spread by root-to-root contact. Nasty stuff. I
saw what it did to elm-ash-cottonwood riparian woodlands in the High
Plains: it was passing through that area while I lived there. Also, many of
the towns were heavily planted to American Elm, and those were lost as
well. Since many of the towns out there are young (1880's), some of the
trees were nearly as old as the towns themselves. Sometimes, whole streets
would be planted almost entirely to elms, and the results were devastating.
This also provides a good example of the dangers of monoculture....

Regards,
Bill

--
Bill Morgan
wtmorgan@pilot.msu.edu
Center for Room Temperature Confusion