Multi-stem Trees - Measuring Circumference

[Will Blozan]

Great discussion.

More than one stem at any height means more than one effort to create wood for the organism.

The height may be the key as Darian suggests.

`Will

[Don]

Although the examples I've seen appear to be pretty clear to me and I'm not sure why there is so much debate about this, I think there are some potential complications if one is using the root collar for determination, as that area can be somewhat muddled. At 4.5 feet above the ground there is less room for interpretation and things are even clearer. Breast height is where circumference is measured, so that should be where the number of trunks should be determined. Otherwise we might as well measure circumference at the root collar.

Darian/Will-
Are we not approaching a circular argument? When you say "Breast height is where circumference is measured...", Breast height is measured FROM the perceived location of the root collar (the proverbial positioning of the original seed that set it all in motion).
The point is, physiologically, a seed sends up a single meristem. Whether or not it chooses to subsequently branch in response to its new environment is another issue. Those that retain a single stem form get measured 4.5' up from that 'seed'; and if the seed branches before 4.5' in height, the multiple stems get measured at 4.5', then get 'normalized' to achieve parity with single-stem contenders. This is fair to both single and multiple stems, and serves as a intermediate step in using 'volume' as a measure of bigness.
This 'normalization' method is sound, and we'll soon be sending out a package for all National Cadre Members that will include, among other items, the Normalization Formula and it's derivation, and an Excel spreadsheet that automates the calculations.
-Don

I meant to introduce the "after" image of the Quad Sugar Maple which was felled a few years after the "before" image...the attached image is of it's cross-section, very near ground level. For scale, note the 8" x 11" sheet of paper in the middle of the cross-section. I've copied it below at the highest resolution I can, you should be able to zoom in far enough to discern multiple 'meristems'/piths, at (or very near) ground level...I can't see them coalescing into a single stem maple within inches further down...methinks this was a cluster of four to five maple seedlings planted together to insure at least one came up...it doesn't take much imagination to see the 'before' image looking evermore AS IF IT WERE a single stem tree that has inosculated its own base, had it lived another hundred or two years.

Does it matter? That is the question we have before us, to arrive at a consensus...may the discussion broaden and continue...: > } [Including the role of measuring girth at breast height!] As Bob would say, we're about to cook with gas!

Quad Sugar Maple Cross-section

[dbhguru]

Ents,

We continue working on methods for computing a functional circumference to compensate for abnormal or atypical forms of tree trunks. Our primary purpose is to support the champion tree programs, state and national.

One approach that Don Bertolette and I have been pursuing for literally months is to investigate methods for computing circumference at 4.5 feet based on the form of the trunk above that level projected down to 4.5 feet. This approach can only logically be applied to compliant trunks that show a predictable taper. The attachment offers computational algorithms. It is by no means a panacea - just another tool in the toolkit.

Both Don and Jared Lockwood are testing the methodology provided in the Excel workbook. They will project the circumference at 4.5 feet using trees that are "well behaved." If the Excel models hold up, then applying at least one of them to trees with distorted shapes at 4.5 feet would seem to be justified. After cataract surgery in both eyes this month, I'll join the testing. Anyone out there in NTS land who would like to join in either with criticisms or helping us test these models, we would be most appreciative. For those of you who have endured my spreadsheet solutions, you'll note that there is usually an introduction followed by a spreadsheet calculator. I usually include the development of any formulas somewhere in the process. In this case, I've eliminated the mathematical derivations and just presented the final formulas. If anyone wants the derivations, let me know.

As some final observations, in the past NTS was the vehicle for developing and applying better tree measurement methods for circumference, height, crown spread, and to a lesser degree, trunk volume. Through our efforts, we have worked our way into a position of importance with American Forests (Measuring Guidelines Working Group and Cadre) and now with the VA Tech Dendrology Dept. Most of our more technical efforts will be expressed through the latter two organizations, but the crucible from which idea spring will likely continue to be NTS.

Bob

[JHarkness]

ENTS,

I hate to reopen an old discussion, but I figured I'd give my opinion on the matter of multi-stem trees.

Trees are extremely complex organisms in terms of the relationships they have with eachother, I'll give you a few examples of some of my trees that have played tricks on me. I have a triple trunk hemlock (actually a double with a trunk-like structure protruding out of it's main trunk, the pith lines meet at almost four feet above the ground), many years ago, one trunk of this tree was injured and bent to the ground, perhaps from a snow storm, instead of turning upright again, it shed it's foliage and grew towards the ground to become a "root" of the other trunk and that is just what it did. It's hardly noticeable now and almost looks like it really is just a root. There are two pines at Ice Glen in Massachusetts that did something similar, one lost it's top, and grew towards the other tree and merged with it, the injured tree has no foliage of it's own, but is alive. How would trees like this be measured once they're fused entirely, and how could someone even tell if they have fused perfectly?

Thanks to excessive deer browse, I only have one mature yellow birch and it's a "double", it's pith lines don't meet, but what on earth is the chance that the only two yellow birches to grow here in the past century grew within inches of eachother? I would guess that this tree is in fact a coppice caused by deer browsing when it was young. That may not be the case, I had one young yellow birch get crushed beneath a fallen tree, three of it's branches turned upright and became trunks, in a few decades, it will likely look like multiple trees.

That brings me to my opinion on coppices, obviously no one wants a multi-trunked tree with small diameter trunks becoming a champion tree (like the NY state champion red oak), but what happens when that tree is given many centuries? Some of those trunks will die, some will fuse, eventually it could all become one single trunk, would it still not be worth being considered a champion tree? What happens if several trees seed in close to eachother, fuse together and grow as 'one', single-trunked, tree? Say five sugar maples seeded in within two inches of each other, in ten years, they're all one form, in three hundreds years, they're a massive single trunk tree, would it be wrong to consider that tree a champion, and how would you know that it originated from multiple seeds anyway? An old growth sugar maple from one seed would probably look exactly the same as several fused perfectly together, and if they seeded in so close and fused together so young, they probably wouldn't get any larger than a tree from a single seed.

I think that the most important thing when measuring multi-stem trees is simply common sense, one obviously doesn't want to measure a triple-trunked spreading coppice that, while it's one tree, shouldn't be the state champion, but one with perfectly fused trunks, or multiple perfectly fused trees, I feel could, and in some cases probably should, get a chance to be included. Unfortunately, many people won't consider that much, take the foresters that the DEC sends out to confirm possible state champions, many of them probably would have no clue about any of this, and most probably wouldn't care to know, they've nominated countless doubles, multi-stemmed trees and coppices, as well as drastically under or over exaggerated the size of the some of these trees.

Perhaps on national and state champion registers there needs to be a place to include doubles and other multi-trunk forms. As Bob said, no one would rather have that ratty-old weevil damaged pine with a 21' girth becoming a champion when the perfect single trunk 150-footer with a 13' girth doesn't get any recognition. But that 21' girth tree is still special, it has still achieved a remarkable dimension. As aesthetically unpleasing as it is, it deserves some recognition. I think that these big tree registers should have singles and multi-trunk trees listed, with multi-trunk trees being clearly marked, or perhaps entirely separated from single-stem forms, perhaps a notes section could be included describing the tree and why it's included?

I've rambled on long enough, hopefully this can be of some use, or at least of interest, for someone here.

Joshua

[Bart Bouricius]

Joshua, some good points, but I don't think that unusual outliers should dictate the rules about what is and is not a single trunk tree. Regarding "common sense" as a method of determining things, Voltaire said that "common sense is not so common". Einstein characterized common sense as "the collection of prejudices acquired by the age of 18". I think both are correct, and I have often found that one persons "common sense" is another's "idiocy". Thus the need for hard rules. Interesting examples though.

[Bart Bouricius]

Actually re-reading your post, not really much disagreement with you, except about the usefulness of common sense.

[JHarkness]

Bart,

I agree, common sense is something that's really not so common anymore. I'm not saying to put "use common sense when measuring a tree" into any kind of tree measuring guide, I'm just saying that not every tree can be determined by the pith test and one may have to go 'out on a limb', so to speak, and guess whether a tree is multi-trunked or single. I'm not saying that that's good practice for the general public, but for those who have experience measuring trees, it could be good practice. I also feel that in certain situations, doubles should be measured together, but just not added to any kind of register unless truly exception in something other than the combined measurements. I know we'd all hate to ignore a national champion if it's pith test shows two trees, but is actually a single tree, but we'd also hate to have a deformed multi-trunk tree take the place of national champion if there's a much nicer single trunk tree that has a few less points. This is where I feel "common sense" needs to come into play, used by those who have experience measuring trees like this rather than used by anyone. I feel that one must have an understanding of how a tree has grown as well, either from historical photos, or by deducing one, or more, likely growth scenarios in regards to past injuries (correlating to dates of major storms or logging activities in the area perhaps?) that may have resulted in a strange growth form.

I'll leave you with a bit of a puzzle I'm trying to decipher, I came across a giant london plane tree recently, at first glance it's an obvious double. But the college which planted it claims to have "planted a london plane tree seedling in 1906", by the pith test, it is two trees that had to have been planted more than four feet apart from eachother, but there's no mention of another tree. Why would two trees be planted like that, knowing that they'd either choke eachother out or become a double, especially when the college has no other doubles? My assumption is that it is a single tree that forked a few feet above the ground in a "U" shape, but as those two vertical limbs got heavier and heavier, it built up more wood between them and below them for strength, that would result in a "\/" shape, seemingly with pith lines that don't meet. Fortunately, I found a historical photo of the tree, it's very poor quality and the tree is not the subject, but it does look like a single that forked about the ground. Also, there's no evidence of a wound where two trees have fused together, it's a perfectly clean, smooth dividing line. It certainly looks like a double now though, regardless of whether it is or is not, I'm not convinced of either yet.

Joshua

[wiloost]

Hi all,

I'm from The Netherlands and have been with you earlier. In 2010 I visited California, Arizona, Utah aso, In 2016 I visited Florida, Louisiana aso. I found a real uprise and surprise of a Live Oak in Suwannee River park. This spring I was again in 7 states in the USA. I have registered a lot of trees on www.monumentaltrees.com. I consider myself to be an educated amatuer. I have had some discussions in the Netherlands with mainly Jeroen Philippona. I have had discussions about Live Oaks with him, especially about the Live Oak in New Orleans; The Seven Sisters. I am an amateur and mainly interested in the photography and records about girth. But I follow your discussions. I have a sugestion. I was in Sacramento in the California State Capitol Museum Park and have registered a lot of trees on the database of monumentaltrees. What intrigues me now is how you would go on with the discussion about measurement of multi-stemmed trees in awareness of the Cinnamon Camphora's in that park. For your help you can see my pics and measurements on monumentaltrees.

Kind regards

Wim Brinkerink

[dbhguru]

Wim, Joshua, Don, et. al.,

This topic is guaranteed to periodically resurface because, as we all recognize, trees don't necessarily behave to fit simple growth models. The big tree programs have sought to address the issue of multi-stems to a degree, but none I've seen address the tough cases.

It was Don's and my eventual acceptance that we couldn't always know the origin of a multi-trunk form. We were influenced by the comments and cautions of all of you. That led us to propose the functional circumference method. It can be applied to trunks at 4.5 feet that have clearly separated and those that haven't. In essence, it seeks to determine the cross-sectional area of wood at 4.5 feet above ground, and back the result into an equivalent circumference of a single trunk of that combined cross-sectional area. This approach assumes that at 4.5 feet above ground level, we're dealing with multiple trunks, which may or may not be separated from one another by space.

On the surface, this sounds like a compromise solution, but we're still left with challenges. Note the three forms below.

In the first two cases, we can easily apply the functional circumference method, but three leaves us with decisions to make. The low lying limb on the left trunk is in the way at our standard 4.5 feet. We could choose to go just above or below it - or both, and average the two. Don and I intended to perfect functional circumference for American Forests, but AF has serious funding challenges for the national champion tree program and is currently following a survival strategy. Call our functional circumference approach a work in progress.

Bob

[Don]

Hi all,

I'm from The Netherlands and have been with you earlier. In 2010 I visited California, Arizona, Utah aso, In 2016 I visited Florida, Louisiana aso. I found a real uprise and surprise of a Live Oak in Suwannee River park. This spring I was again in 7 states in the USA. I have registered a lot of trees on http://www.monumentaltrees.com. I consider myself to be an educated amatuer. I have had some discussions in the Netherlands with mainly Jeroen Philippona. I have had discussions about Live Oaks with him, especially about the Live Oak in New Orleans; The Seven Sisters. I am an amateur and mainly interested in the photography and records about girth. But I follow your discussions. I have a sugestion. I was in Sacramento in the California State Capitol Museum Park and have registered a lot of trees on the database of monumentaltrees. What intrigues me now is how you would go on with the discussion about measurement of multi-stemmed trees in awareness of the Cinnamon Camphora's in that park. For your help you can see my pics and measurements on monumentaltrees.

Kind regards

Wim Brinkerink

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Wim Brinkerink---Your post makes many excellent points, and I'll address the question you ask about the Cinnamon camphoras in the Sacramento Capitol Park. Identifying them by their measured girth numbers (6.83 and 6.21, as appearing in the Monumental Trees webpage you've recommended), your selections serve well to demonstrate the breadth of forms that we have to provide simple rules for. From my perspective, I make no judgement as to superiority of single- versus multi-stemmed trees. I do think they deserve parity in their measurement though. By parity, I mean to say, judged equally and fairly, which can be done through the use of a Functional Circumference formula that we recommend. By fairness I mean to say that parity is achieved through a mathematical formula that views these trees in terms of circumference(s) and basal area(s).
Based solely on the images, I would tentatively judge both of the Sacramento Cinnamon camphoras to be multiple-stemmed, and to be correctly measured, should include all stem's girths encountered at 4.5' in height, which should then be entered into the Functional Circumference formula, that they may achieve parity with single-stemmed contenders, and for that matter, that they may achieve parity with other multiple-stemmed contenders, no matter how many primary stems. Until a solution superior to Pith line Delineation arises, the perception of a tree's central axis should guide the determination as to single- or multiple-stemmed decisions. Please visit American Forests online Measuring Guidelines at: https://www.americanforests.org/wp-cont ... nes_LR.pdf, in the Circumference section (pages 8 - 23) and for additional supporting information, the Appendices found in pages 74-86 may further clarify these issues.
Don Bertolette