HELP: Fungus on Elm

davekate davekate at
Mon Mar 20 12:39:23 EST 2000

The "tears" are sap. The crud growing in the sap is mainly bacteria and
probably some fungi too. The bleeding will eventually stop, probably without
any harm to the tree as far as I know. I have read research summaries on the
bleeding of maples from spring pruning. The upshot was that it did not
significantly  harm the tree. (Not to say that large cuts will not grow
wood rotting fungi)

Topping, on the other hand does significantly harm trees. Ironically many
people prune like that to reduce the chance of branches dropping on their
houses. However the suckering branches  resulting from the topping will be
weakly attached and in time will be more likely to split off and fall. The
natural form of the tree and thus the esthetic quality of the tree is
ruined. IMHO stubbed branches and the upspringing of all the suckers is
ugly.The longevity and health of the tree is reduced because the big open
wounds will allow disease organisms to enter, since it cannot "grow closed"
quickly enough. I like to suggest that if someone wants to top a tree, do it
at 6" from the ground. If you had a "professional" do it for you and they
did not warn you of the consequences of topping ... well, I guess I
shouldn't get started on that one.

A better way of pruning  to reduce height is to do "thinning" cuts (i.e.
Shorten up branches by removing one of the branches at a crotch), thereby
retaining the natural structure of the tree, instead of Topping (or  stub
cutting or "hedging" cuts) which radically changes the branching structure
and form of the tree.

Desiree Martinez <drmartin at> wrote in message
news:8b0ipp$9h$1 at
> I ahve atree that we just had trimmed, Basically toped. My mom says it's a
> Japenese Elm.On one of the limbs that was cut, it started to "cry", not
> sap but water dripped from it. Now after three weeks, a white foam or
> fungus is started to grow on the limb. What could be wrong? Any clue?
> --
> Desiree Martinez  drmartin at Univ. of Penn,1995 ,_,
>                  Harvard University, 2002                    (o,o)
>     "It's a Hahvahd thang and you just wouldn't understand"  {`"`}
>                -"-"-

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