American Forests MGWG

General discussions of measurement techniques and the results of testing of techniques and equipment.

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dbhguru
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Re: American Forests MGWG

Post by dbhguru » Wed Sep 11, 2013 8:16 pm

NTS,

It is time to bring everyone up to date on AF MGWG progress. I am pleased to report that Don's Tree-Aj is alive and doing well. Don has expanded the format and put forth the idea of hypelinking terms to more detailed explanation. The measurer drills down to obtain detail on measuring methods and instruments. There will likely be multiple drill downs. This approach will keep the structure together. Sheri Shannon has asked that Don and I cover the advanced measuring methods in the context of Tree-Aj. Sheri will cover similar triangles, and the remaining members will deal with intermediate methods. Read that conventional tangent method plus equipment used for that method.

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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Don
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Re: American Forests MGWG

Post by Don » Thu Sep 12, 2013 2:59 am

Ed-
It's definitely not to my credit that I haven't been to the NTS contribution you've made to the Wikipedia coverage of tree height measurement until recently. I spent this evening trying to put in words what it is we (MGWG) need, and part of that involved reviewing your take on tree height measurement.
I'd scanned it when it first appeared, but I didn't have near as much involvement then as I do now. That said, there's a lot to be liked in your presentation. It's clear that you've tried to present it to a lay audience.
It's subtle things I think, and not easy to put in words...for example, it was a sine-sine figure I saw that showed the measured slope distances going to the tip and the base, in a solid line, but the remaining dimensions (vertical line going down from tip, up from base, horizontal lines going from laser to trunk) were dotted/dashed. That clicked with me, almost like an epiphany...we didn't care about distance to trunk, or what it did between the two horizontal planes. And at least 'symbolically', there wasn't even a line going straight between tip and bottom...it was not measured either, it was calculated.
These probably sound elemental, but as a geometry/trig student, I never really got it.
I used to feel badly, and have worked to grasp the elementals and now have a much better handle on it. My point? There's a lot of folks out there that don't, and they're the ones we want to reach.
If it's alright with you, I'd like to steer one or two of our group (MGWG) to your handling of the Tangent Method, and the Sine-Sine Method. Your account of the transition from Tangent to Sine-Sine was excellent, puts us in a good light.
Thanks!
-Don
Last edited by Don on Thu Sep 12, 2013 10:54 am, edited 1 time in total.
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Science Center
Grand Canyon National Park

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edfrank
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Re: American Forests MGWG

Post by edfrank » Thu Sep 12, 2013 10:19 am

Don and Bob,

You can use whatever I have posted on the BBS, NTS website, in articles, wikipedia, or in any of my comments or photos if it would help make your case.

Ed
"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky

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dbhguru
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Re: American Forests MGWG

Post by dbhguru » Sat Oct 26, 2013 6:48 pm

NTS

On Friday, the AFMGWG met for our monthly meeting. We're moving rapidly forward with our measuring guidelines. Sheri gave a thumbs up on what Don and I have produced. We have now covered height measuring techniques pretty thoroughly. It is just a matter of working toward ever clearer diagrams and explanations that AF believes will work for the certifiers. This is not equivalent to Don and I explaining the measuring techniques to our satisfaction. It is a matter of explaining the techniques to their satisfaction. It requires a lot of experimentation. AF will handle the final graphics, which is fine by me.

Now it is on to explaining methods for measuring crown spread and revisiting the 1/4th weighting factor. Should the factor be changed? If so, to what? We're in our infancy on dealing with crown spread. Ideas are most welcome. Of course, I'm pushing the spoke method, but truthfully, I haven't thought about how to take crown measurements most efficiently when the tree presents special measuring challenges. For example, if part of the crown is inaccessible in terms of walking to a point beneath it, then what methods do we have for dealing with the part that is inaccessible?

If the measurer has a laser, clinometer, and compass, then the horizontal distance between the trunk and the end of a limb can be computed using the law of cosines. This would be another spoke in the spoke method.

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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