Loose bark - can it be okay? Tell me!

[M.D. Vaden]

Last week, I was called for an estimate for tree removals.

There had been one arborist out before me.

The neighborhood is well forested, and damp and moist in fall and winter in Beaverton, Oregon. A lot of shade during many rainy cloudy days.

One tree, a big Douglas fir in the front, I doubt, really had root rot like the other arborist told the homeowner. The tree had some lichen on the bark. But the top was very healthy, great needle size, no evidence of rot, or fungus anywhere. There was a hole that was drilled (not a core sample) a few inches into the tree from the other tree guy. I don't think that a tiny hole 5" in and 3/16" diameter could really show much.

Anyhow, my main question is due to trees in the back yard. Same type of trees. About 12" DBH - the ones squeezed in on the interior of a thick grove, only foliage way up.

The other tree man showed the homeowner that bark came loose. So I tried pulling myself. Some of the 3/4" bark on these 40 to 50 year old trees did pull loose without major effort. Although its not like it falling off.

The other tree guy said this meant the trees had disease.

Now the bark did not peel loose to the cambium. In a few spots there was some channelling from critters, but very little.

So, this got me to wondering - do healthy trees have bark that can be worked loose if they are in a moist damp shaded forest environment for a major portion of the year?

It occurred to me, that I have never read anything about that before in any book or magazine. But it seems reasonable that bark would decompose a little after many years in a moist environment.

I'm not really looking for input about whether or not this tree guy was correct or not - although, shoot away if you like, we know how the forum goes.

But my main interest is concerning the condition of bark on healthy trees in damp atmospheres after a period of time.

Let me know what you learned from experience, or may have read or learned.

Thanks,

Mario Vaden
Arborist / Landscape Designer
Beaverton, Oregon



So it crossed my mind that maybe its acc

 

[Tom Dunlap]

I've seen the corky layers of bark pull off trees. Unless the bark comes off down to the cambium I haven't seen a problem.

You should contact a forest scientist in your area. Doug firs may have some normal bark shedding.

Tom

 

[NeTree]

Ditto to Tom.

If root rot is suspected, you may want to do some more testing in those areas.

I would also investigate the borer infestation more, and determine if treatment may be needed there, as well.

Sounds like you're trying to do the right thing.

 

[treeman82]

Sycamores will regularly shed their bark. It sounds to me like the other arborist used a resistograph on the tree. I could be wrong though, because I have no experience with them.

 

[John Paul Sanborn]

many people will use a fine drill bit to examine a tree for hidden decay. using a sharp bit and paying attention to the resistance, one can get an idea where the punk starts. Watching the frass come out you can see where the discolored wood begins alos.

A foam ear plug on the bit can act as a simple depth guage.

 

[Stumper]

Tom got right to the crux of things. If you peeled bark down to the cambium something is amiss. if you peeled a bark scale-no biggy. That is why many species have "scaley bark" as part of the discription.

 

[M.D. Vaden]

Regarding drilling for frass:

A forestry education center in Portland had a sample on display - a Douglas Fir. It had about 80 rings in the center 8" of diameter, and about 25 rings on the outer 16".

Something kept the tree growing slow for the first decades, whether shade or some other factor.

That inner wood was much darker - very discolored - from the outer wood. But all the wood was strong, sound wood.

Apparently, the same situation could happen at any part of the trunk.

Via drilling a 1/8" to 3/16" hole, how would someone be able to tell punk frass from a darker or discolored healthy wood? All the drill chips would be very tiny by the time they were extracted.

I don't think I would be able to detect for sure.

On the other hand, I've seen devices for extracting a core of about 1/4" to 1/2". With an entire intact core that size, I think I'd stand a chance of a right decision.

 

[John Paul Sanborn]

Practicing on common species regularly. With the punk you can tell with resistance of the drill. This is the same theory behind the reisitograph, but much cruder.

With the frass, it's once again a mater of experiance.

Incremental borer is another method, but with the larger hole, much more invasive.

The only time I've done drilling is to assess a tree prior to removal. Determining how solid the trunk is and how much holding wood I'll have to tip the spar. can I use this angle of fall, or will I have to go another direction and shorter stick.

 

[M.D. Vaden]

A question of curiosity for the Sanbornmiester - if a tree has no outward signs of any disease or deterioration, not on the trunk, the roots, the needle size, no stress cones, no bugs - it it reasonable to do a probe?

 

[John Paul Sanborn]

The only time I have done it is when there are visual indicators and/or hollow thump.

IMO any invasive testing is to evaluate those visual/audible defects.

Some trees we will just assume some decay after a certain DBH. , but if there is no outward sign of a defect that compromises cyindrical strength, then invasive testing is not realy needed.

If you have a tree that is not presenting any of these defects and is not intended for removal, then the only (ethical) reason I could see for doing any invasive testing is if there is a need for the owner to have a varifiable risk assesment. Then I would strongly recomend using a resistograph, becasue the tapes will be a hard document that can go into a file.

There are some new toold in development that use computer aided (RF?) tomography to assess wood conditions. Small tacks are tapped in around the circomferance. When this becomes available (At a price under the 14k quoted at a conferance) it will be very usefull.

 

[ORclimber]

I've worked on lots of Doug-firs with flaky bark, stick a hook in and a big chunk breaks off. I'm no forest pathologist, but I have dissected many fir trees and haven't seen any correlation between flaky bark on Doug-firs and disease. The only time I've seen Doug-fir bark flake off all the way to the cambium, the tree is obviously dead(brown needles) or there is some kind of mechanical injury(hit by car). The only obvious ways I know to tell if a Fir tree has root rot are conks or dying top. At OSU we were taught that in fir trees bark beetles are usually a secondary infection after the trees had been weakend by something else, root rot, drought stress, whatever.