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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American Forests MGWG

Post by dbhguru » Fri Aug 30, 2013 4:02 pm

Hi All,

Well, we just had our monthly meeting of the American Forests Measuring Guidelines Work Group. It went very well. We are going to develop measuring guidelines for all techniques in the form of one-page diagrams. This is where Don and I could use help. My diagrams tend to emphasize the mathematics too much. We need truly comprehensible diagrams. We can also have diagrams that illustrate common errors associated with each technique. We will have a primer on trigonometry. Ideas are welcome on all fronts. American Forests is cooking with gas.

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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pattyjenkins1
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Re: American Forests MGWG

Post by pattyjenkins1 » Sat Aug 31, 2013 2:29 pm

Bob and Don,
I can't help with this, but congratulations!
patty
Patty Jenkins
Executive Director
Tree Climbers International, Inc.
Get High / Climb Trees

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dbhguru
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Re: American Forests MGWG

Post by dbhguru » Sat Aug 31, 2013 8:47 pm

Patty,

Thanks. Don and will explain how our fellow and lady Ents can assist. We're further along toward making significant changes to the way the National Register is run than has been the case for years - maybe ever. NTS can play a major role in the measuring guide, Tree-aj, a cadre of super measurers, rules for multiple versus single-trunk trees, a database of tree maximums (we have a great one taking shape thanks to Matt), and ultimately, a certification program. Don and I will explain how others can participate by helping us in future posts. Happy Labor Day every one.

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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edfrank
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Re: American Forests MGWG

Post by edfrank » Sun Sep 01, 2013 9:01 am

Bob,

I am not sure if you are hinting, playing some game, or dismissing.... I have included diagrams of the stick method and the NTS sine method for measuring height, diagrams for various situations for measuring girth, and diagrams for measuring crown spread using the longest/shortest method and the spoke method in my Wikipedia articles. The only diagrams missing are ones showing the clinometer distance method, and diagrams demonstrating the pith method. If this is the style wanted, I can do one for the clinometer distance method. The pith trace method I think would be better served by using photos with the pith marked rather than a diagram.

Edward Forrest Frank
"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 » Sun Sep 01, 2013 8:49 pm

Ed,

No, I'm not playing games - certainly not with you or NTS. Nor am I dismissing or hinting. I am exploring different approaches to the issues that the Group is debating. It requires finesse.

In the past, I diagrammed all the relevant methods of height measuring ten ways to Sunday. Nothing was left to chance. I presented them in tree-measuring workshops, briefings, and in BBS posts. So, as for diagrams, been there, done that.

You migrated our methods to Wikipedia plus added a couple of your own. And you did a fine job. We all are grateful. So now, you too have been there, done that. The same thing can be said for Will in his ENTS measuring guide, and of Bob Van Pelt and his tree-measuring guide and of Michael Taylor. BTW, BVP has some of the best diagrams of all.

My point is that there is no shortage of tree-measuring diagrams dating back into the mid-1990s. But forest mensurationists have not flocked to our sine-based methods, so, the job of persuasion must go on, because AF, as an organization, is understandably influenced by what forestry academics promote as valid methods.

In terms of Don's and my participation in the AF initiative, we have made it plain that we want to involve the rest of you. That said, it is a question of what kinds of diagrams do we need that will satisfy the MGWG? I'm unsure, but I have a sense that AF needs a little measuring mascot with a cute name. Something warm and fuzzy that is shown with an instrument looking at a tree.

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

Joe

Re: American Forests MGWG

Post by Joe » Mon Sep 02, 2013 6:45 am

dbhguru wrote:But forest mensurationists have not flocked to our sine-based methods, so, the job of persuasion must go on, because AF, as an organization, is understandably influenced by what forestry academics promote as valid methods.
I think you should give up on forest mensurationists- they don't have a clue and never will, that is, regarding precision tree measuring- because they don't care. What they care about is measurments for basic forestry purposes. If they have managed to claim to be the experts- it's clear they are not. Pretend they don't exist.

Precision tree measurment (PTM) is a field unto itself- it should declare itself that way, in my opinion. PTM is more of a subset of engineering than forestry.

Forestry is NOT a science, it is a practice. Engineering is also a practice but a far more precise one- where measurements are critical.

Numbers in forestry are always imprecise.

Joe

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Will Blozan
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Re: American Forests MGWG

Post by Will Blozan » Mon Sep 02, 2013 7:43 am

Joe,

Well said. The term for PTM is "dendromophometry".

Will

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dbhguru
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Re: American Forests MGWG

Post by dbhguru » Mon Sep 02, 2013 8:19 am

Joe,

I like your characterization of what we do as precise tree measurement (PTM), and as a separate field, if only informal at this time. I frequently make the point that measuring well-behaved trees for commercial purposes and developing a discipline to standardize the measurements is a different animal from measuring the behemoths that make it into champion tree lists. Some of the champs have crown spreads of 120 to 160 feet, possess a short lower trunk, and exhibit multiple, competing tops that are literally spread over an area as large as 1,000 square feet. What a different animal from the simple tree diagrams that show a well-behaved form with its highest point positioned vertically over its base. Witness the Pinchot Sycamore in Simsbury CT. and many of the trees that Larry Tucei Jr. measurers, to say nothing of the west coast deciduous giants. Those forms are about as far removed from a plantation Norway spruce as it gets. And measuring them sensibly requires that we think outside of the proverbial box, which of course, is what we've been doing.

I do respect the different objectives of tree measuring when viewed from a forestry perspective. Since my background is not forestry, I hesitate to go very far into characterizations, but I do see that within academic circles, there are now a few mensurationists who are seriously examining our methods. We have a foot in the door. Of course, others are not budging with respect to the older methods. That is being human.

I'm more philosophical and pragmatic about changing minds than I used to be. I believe that over the next few years we can bring aboard a good representation of forest mensurationists, and that will speed up the acceptance of our more advanced measurement methods. More to the immediate situation, I have to accept that American Forests, as an organization, will continue to be influenced by input from traditional sources, i.e. field foresters and academic forest mensurationists. So, every step forward in this environment may be accompanied by half a step back, but we are gaining ground.

I'll close by presenting the results of a recent photo-measuring exercise. Note that the photo-measurement came within 0.8 inches of the circumference measurement using a tape. Jake is about as round as we're going to see.

The photo method requires a tape (or rangefinder), a digital camera, a foot ruler, and the free software ImageJ, which was suggested by fooman (Matt) in Australia. Darn good recommendation, Matt. Many thanks.

To take multiple measurements from one photo, ideally, the measurer chooses a location, positions a foot ruler 90 degrees to the line of sight near the center of the photo, records the straight line distance to the center of the ruler, and then shoots to points on tree trunks that can be at varying distances, and records each distance. All targets should be within the center half (Don Bertolette's suggestion is one third) of the image. This method is low tech, low cost, but amazingly accurate.It competes with the use of a reticle and the expensive LTI Criterion RD1000 Dendrometer, at a pricey $1,500.

Don and I are hoping to get the photo method accepted by AF as part of the evolving guidelines to measure trunk thickness and compute girth for trees where the measurer cannot reach the point of measurement with a tape. It happens.

Bob
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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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edfrank
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Re: American Forests MGWG

Post by edfrank » Mon Sep 02, 2013 12:27 pm

Bob,

Excellent results with your photo measurement. About diagrams. You and Michael developed the sine method and diagrams. You and Will and BVP have all developed excellent diagrams to illustrate tree measurement. When you worry about the change in elevation due to the rotation of the survey instrument as you point it up and down, you need the detailed mathematics. You need that degree of accuracy to do the demdromorphometry stuff we as a group, ad you as individuals are trying to accomplish. In my Reeally Really basic guide to laser tree height measurement and in the Wikipedia articles, I used more cartoonish diagrams that contained the minimal information to convey the process. I thought they would be less intimidating to those people who are math-reluctant. All of the equations and derivations do not need to be incorporated onto the diagram itself, but a simplified "do this and do that to get this" type of an explanation can be included in the text itself to elaborate and illuminate the base equation included as part of the diagram.

If you look around on the web, you have illustrations, BVP, has illustrations, AF, me, everybody has their own diagrams on how to measure trees. They may or may not share the same nomenclature, there are differences in the illustrations themselves. There are even differences in the processes. It is confusing to someone starting out with tree measurement. Many sites have diagrams drawn by the site owners because they were unsure about the propriety of using someone else's diagrams. That is part of the reason why I wrote the Wikipedia stuff- to pull everything together and to provide public domain diagrams that others could use.

I really believe, and it is not just my ego talking, that the best option for American Forests would be to use the diagrams I have included in the Wikipedia articles as the diagrams they use on their website to illustrate tree height measurement, girth measurement, and crown measurement. I can create drawing in a similar style for whatever else is needed. In this way when someone looked at Wikipedia and looked at American Forests they would see the same diagrams and see the same basic explanations. It would provide some consistency. I think these Wiki diagrams will begin to appear elsewhere on other sites. The diagrams are simple but mathematically correct. They are easy to understand and not intimidating. It would be good policy on the part of AF to help weed out the confusion existing on the web by using the same diagrams. There is no downside to doing this. We can all work to make the explanations as basic as possible, but the place to start is using my diagrams. Your diagrams, Will's and Michaels are needed for our more precise demdromorphometry and can be referenced by AF, but they should not be the ones first presented to the general public with the plethora of equations and math.

Edward Forrest Frank

.
"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 » Mon Sep 02, 2013 1:14 pm

Ed,

I have no objection, at all, to pointing the Group toward your easy-to-follow Wikipedia illustrations to test the receptivity of the others to adopting those diagrams. Consider it done. I'll let you know how it turns out.

At the present, I'm also responding to a communication from one of the other members about what should minimally be acceptable (height measurement wise) for a tree to be accepted into the National Register. For instance, would we accept a measurement if: (1) it passed a screening test using a course filter for maximum heights based on data from the Forest Service and NTS, (2) it passed a photo inspection test (the claim of a 300-foot dogwood should surely fail), and (3) the measurer used crown cross-triangulation or lined up so that the vertical plane containing the top and base was perpendicular to the line of sight in applying tangent calculations? I think that two of the Group members would like to see such a tree pass the height test. They have some good arguments.

In response, I'm experimenting with the idea of provisional status. I think Don is on board with the idea. Let's say a tree is measured by a tangent method of either of the above two types. We could give it provisional championship status until sine-sine were done. An asterisk would denote its provisional status. By contrast, I'm not backing off excluding the conventional tangent method as acceptable for a tree at the national level. As we agree in NTS, there are far, far too many abuses of the method. We would gain nothing were we to allow the conventional tangent method to be used for height. The argument has been made that the conventional tangent method is the one built into 3-point method hypsometers. I acknowledge this, but explain that the 3-point method virtually guarantees errors. Any thoughts?

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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