Dr. Claus Mattheck is currently touring the US, presenting a 2-day workshop at 4 locations. While it's probably a bit late to think about attending, those of us who attended can discuss what we learned.

Who has attended the workshop, and what did you think? Did you learn from it or is it all just hooey? There are probably many questions that didn't get answered. Post them here, and we'll discuss them. Maybe we can even entice Dr. Mattheck to drop by here sometime.

Reply to post by Russ Carlson, on June 11, 1999 at 19:22:02:

This was the third time I have heard Mattheck speak and I think I have finally got it.... (I happen to have an engineer for a wife and that helps).

One thing that I am still not clear on is the importance of "whole-tree" subsidance on an otherwise in-tact tree. Other than monitor which in some contracts is not an option, how should it impact your opinion of the trees structural health?

Wayne

Reply to post by Wayne Cahilly, on June 11, 1999 at 19:22:02:

Not sure I can answer, Wayne. I haven't studied subsidence (a form of fiber buckling, I think) enough to know how quickly it occurs and what ramifications it has to tree care. Add in the difference between gymnos and angios, and it seems a little confusing to me yet. This is one aspect I need to work on.

Reply to post by Russ Carlson, on June 14, 1999 at 13:35:57:

I liked Mattheck's Body Language and even Design in Nature a lot but, as an educator, I thought the so-called "workshop" was a waste of time and money. He is presenting old stuff at this point, it was amazing boring for me to go through the book that came with the seminar page-by-page, and his touchy-feely interpretations of individual tree slides is really questionable.
Here is a point I tried to get him to answer, and that has a lot of impact on those of us evaluating the hazard of internal stem decay. If you look carefully at his t/R graphs, it quickly becomes apparent that the formula is highly species-specific, no matter what he asserts. The graph for oaks, for instance, shows a very low percentage of failure for large trees, even when t/R 1/6" instead, which is much easier in the field, where you always measure DBH?
The workshop was mostly old smoke and dirty mirrors for me.

Reply to post by Russ Carlson, on June 14, 1999 at 13:35:57:

Thelast part of my comments was supposed to read, "even when t/R is less that 0.30. And why doesn't he use t/D is greater than 1/6 instead...."

Reply to post by Jerry, on June 17, 1999 at 22:41:49:

He doesn't use t/D because he is not using the diameter or the radius of the stem. R in t/R is the radius from the center of the decay to the outer wall of solid wood. If the decay is not centered in the stem, there will be a big difference.

The problem with this is knowing where the center of decay is. You need quite a few test holes at the same level to be able to accurately sketch the decay and find R.

The other problem is with measuring t. Where do you take it? What about open cavities (t = 0)? The wood at the edge of a cavity often is tapered, so where do you measure?

Still a lot of unanswered questions, but at least we are making some progress toward understanding all this.