i am interested in the forums opinion about the following scenario:
you have a cavity in a tree which is periodically waterlogged then
dries out is collecting leaf litter etc and has decayed wood tissue
extending down into the trunk for 12inches/30cm.

my question is this: do you leave the cavity alone and try to
assist the tree's health through mulching watering etc and hope
that the tree will prevent further decay through effective
compartmentalisation?

or do you try to stop further decay by preventing water and
debris entering the cavity and perhaps innoculating the site with
trichoderma funghi which will parasitise the wood decay funghi?

your opinions and any supporting references would be
appreciated
mark lutherborrow

Reply to post by mark lutherborrow, on February 11, 2000 at 07:17:30:

Mark,

Leave it alone. Filling it will not help and draining it will hirt (shigo).

More importantly is the nature of that wet wound. Fortunately fungi is an
external metaboliser. It therfore in general does not do a good job of decaying
in water. Moist areas decay well wet areas do not. Additionally there are often low levels
of oxygen in water which is often wanted in high levels by fungi.

Mark

Reply to post by Mark hartley, on February 11, 2000 at 07:17:30:

mark,

"leave it alone", you say.
is this the best we,as arborists, can do ?
i find this very hard to accept.
if you have a mature tree that you want to preserve can you just leave it alone?
shigos theory of compartmentalisation is evident through examination of wounds on trees.
but this process of compartmentalisation is not 100% effective, otherwise why do cavities extend/ deepen with time?
if indeed these fungi are aerobic then should we fill all cavities with water to prevent further decay??
seriously though is the "hands off" approach good enough?

mark lutherborrow

Reply to post by mark lutherborrow, on February 11, 2000 at 21:57:51:

Mark,

Do you have any better ideas than "Leave them alone"? I have suppested to clients that setting up a plumbing system to keep the cavity filled with water would be the best "cure". It would not be hard to install. No different than an ice maker for the freezer. So far, no takers...

Check out these articles on stopping wood rot on boats. I think that there might be some value in using this technique on trees.

http://www.greenbuilder.com/sourcebook/WoodTreatment.html


http://www.rotdoctor.com/


There would be trade offs in using some of the treatments since some of the chemicals might be toxic to some tree tissue. In my thinking, if these processes work on lumber why not on trees?

Tom

Reply to post by mark lutherborrow, on February 11, 2000 at 21:57:51:

Mark, what is wrong wtih simply saying "We can't do better than Nature?" We don't have the ultimate answer to everything (yet), and the response of the tree is still better than our rather feeble attempts to treat wood decay in living trees.

The compartmentalization in trees is not perfect in the interior directions. "Wall 4" does a good job, as intended. Internal spread is limited, but not stopped. The result is the race of decay against new wood growth; will the tree weaken faster than it strengthens?

The materials used to treat decay in boats are known to be toxic to living cells. There is a big difference between working on a living tree and on a piece of cut lumber. We are making progress, but the best answer is still to leave the tree to its own defenses.

Reply to post by mark lutherborrow, on February 11, 2000 at 21:57:51:

Mark,

There is a big difference between pathogenic fungal activity and
saprophitic decay of dead tissue. There is an obvious benefit in
arresting pathogens. The tree however has a wonderful system of
dealing with cavities. compartmentalization is part of this but more
importantly is the overengineering that exists within a tree (mattheck,
Wessoley etc). We need to stop thinking of trees as nongenerating organisms.
Provided decay does not advance at a rate great enough to reach structural
failure it does not matter that the cavity is there.

There is a good conference comming up this year in Sydney on fungi for Arborists.
I will keep you posted.

Mark

Reply to post by Mark Hartley, on February 12, 2000 at 01:41:20:

mark ,
i appreciate your feedback and you have made some valid points.
i would be keen to attend the fungi workshop you mention so please let me know when its organised
thanks
mark lutherborrow

Reply to post by mark lutherborrow, on February 11, 2000 at 07:17:30:

Cavities have an innate value as habitat. Loss of natural cavities, partly thru over-zealous human management, contributed to decline of the eastern bluebird. I saw a presentation once by an arborist who makes money producing cavities for wildlife habitat.

Reply to post by Ed Milhous, on February 11, 2000 at 07:17:30:

Do you know what methods he used to create the cavities for wildlife, what kinds of trees, or what wildlife species in particular? We have a riparian area under restoration. In the past there have been wood duck boxes put up. It would be good to know what others have done, with the how and why of it. Other than removal of exotics and replanting of natives, a leave it alone approach seems to apply. But if some pruning was needed for public safety, it would be good to know if wildlife habitat was able to be enhanced or protected, rather than eliminated in the process.

Reply to post by Mark Goodwin, on February 19, 2000 at 09:33:12:

Cavity recipe:
Good for a spar, or you can use a log and hoist it back up into an existing tree, pole, rock outcrop... whatever is available. Obviously, good judgement is necessary here.
1. Make two cuts along the trunk axis, about 8-10 inches apart, angled toward and meeting at the trunk's center.
2. Plunge chain saw into trunk at top and bottom to free the wedge of wood; leave solid wood above and below. Make it small enough that you can handle the wedge when it comes loose.
3. Cut tip (from center of tree) off the wedge. How much of the tip you cut off determines size of cavity; but you can hollow out the tree's center where the wedge was removed with a saw.
4. Cut a slot into the wedge to serve as an entry point. Best to do this about 1/3 to 1/2 half way down the length of the wedge, leaving solid wood above and below. Some critters want to go in and up; some go in and down. Size of slot will determine who can use the hollow w/o alterations, but they will alter it to suit there needs.
5. Reattach wedge by nailing or screwing it back in or strapping it in w/wire or old rope.

I've heard some say the orientation of the entrance determines who will consider living in your cavity. Perhaps, but most any cavity I see is inhabited by someone!
I would think this would be a good thing to do w/exotics you mentioned: frill & kill them, or girdle them, and make a cavity in them.