Longest Limbs

Longest Limbs

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TOPIC: Long Limbs
http://groups.google.com/group/entstrees/t/71dd170fdf856156?hl=en
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== 1 of 7 ==
Date: Tues, Dec 16 2008 4:05 pm
From: "Edward Frank"

ENTS,

On the 4th Bob Van Pelt posted a list of some of the longest unsupported branches he has documented in west coast trees. This is something we could measure for our impressive trees in the east. He is focused on unsupported branches, but I think we could include branches that are lying on the ground or artificially propped could be measured and included so long as these facts were noted. Scott Wade commented that he has only measured one long limb, a pecan with a 78 foot limb, but there are sycamores he has measured with 80 foot limbs, although one was propped with a crutch. Carl Harting and I measured a white oak limb on Lencer drive just north of Cook Forest at 68 feet. I would measure limbs as the maximum distance from the center of the trunk in one direction, or from where it branches from the main trunk if the tree is seriously tilted.

Thought anyone?

Ed Frank

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TOPIC: new 27' sycamore found
http://groups.google.com/group/entstrees/t/72f66ea58161d8ff?hl=en

== 1 of 1 ==
Date: Thurs, Dec 4 2008 7:41 am
From: BVP

....My current list of long branches on the West Coast (self-supporting,
non-cabled branches!) includes:

94' Juglans hindsii x nigra
81' Quercus lobata
78' Quercus chrysolepis
77' Platanus racemosa
72' Juglans hindsii x regia

The East Coast record (maybe)
92' The Gifford Pinchott Sycamore in Connecticut.

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== 2 of 7 ==
Date: Tues, Dec 16 2008 4:10 pm
From: James Parton

Ed,

Sounds like a great idea! The first ones I think of are those huge
limbs on the Angel Oak. I also remember Will commenting on a long limb
on an oak at Biltmore during the Black Mountain Gathering.

JP

== 3 of 7 ==
Date: Tues, Dec 16 2008 4:54 pm
From: dbhguru@comcast.net

Ed,

I like the idea of measuring the longest limb of trees with conspicuously long limbs. The challenge is not trivial for limbs that are partially obscured. More on this topic to come.

Bob

== 4 of 7 ==
Date: Tues, Dec 16 2008 5:52 pm
From: "Edward Frank"

Bob,

I can't decide if the starting point should be where the limb emerges from the trunk or from the center of the tree. I go one way then the other.

Ed

== 5 of 7 ==
Date: Tues, Dec 16 2008 6:24 pm
From: "George Fieo"

Ed,

Would the list be for each species or all combined or both.

George.

== 6 of 7 ==
Date: Tues, Dec 16 2008 6:17 pm
From: "Edward Frank"

George,

A combined list. As I see it, the longest limb would only be measured for those trees with exceptionally long limbs. Most species would not be represented at all, and only those with the longest limbs would be measured for those species that were represented. It would not be something measured for every tree, so the number of examples on the list would be relatively small.

Ed Frank

== 7 of 7 ==
Date: Tues, Dec 16 2008 6:58 pm
From: doug bidlack

Ed,

do you know what BVP does? That seems like a good place to start...at the very least a good discussion. I'm glad you brought this up because I was just recently thinking about it. I'm hoping to measure some Michigan AF champion trees when I visit my parents for Christmas. I was planning on measuring the longest limb on each tree. I was thinking to do this for each tree species, not just the ones with the longest limbs and I was also planning to have separate measures for longest unsupported limb and longest supported limb.

== 2 of 3 ==
Date: Tues, Dec 16 2008 7:14 pm
From: "Edward Frank"

Doug,

I don't know what BVP does. He did mention the idea when we were down in the Smokies this spring, but not any details. For now if I had a candidate, I would measure both until it was decided. The white oak I mentioned was 71 feet from the center of the trunk and 68 feet from the surface of the trunk.

George ask about lists for individual species or a combined list for longest limb. I don't think the longest limb is really all that definitive of a measurement for use in describing a tree species, but more along the lines of something that is simply interesting. I really think the best way to characterize the crown size is by doing an average crown spread measurement. I think the spoke method is the best way to do it. I try to encourage people to measure crown spread for any large tree, but then at the same time I find myself lax in doing it in my own measuring trips. I will try to do better, and hope others will do the same.

Edward Frank

== 3 of 3 ==
Date: Tues, Dec 16 2008 7:57 pm
From: "George Fieo"

Ed,

I collect shed antlers and use a measuring system to score them. There are
several measurements required, length of main beam, tine length, and
circumference of beam. It's very similar to measuring trees. To get the
tine length you would measure from the top of the main beam to the tip of
the tine so if the tine represents the limb you would measure from were it
emerges from the trunk. Just a thought.

George.

== 2 of 12 ==
Date: Wed, Dec 17 2008 4:56 am
From: dbhguru@comcast.net

Ed,

I think BVP measures from the trunk. At least, that is what I think he did for the long limb of the Pinchot sycamore. What does Will think? Will?

Bob

== 3 of 12 ==
Date: Wed, Dec 17 2008 6:58 am
From:

Bob,

You'd have to measure to the trunk - it's the only aspect of the length that you can actually MEASURE. How could you measure to the center? You can't guess or calculate where it is. On many trees, the center of the pith is very far from the geometric center of the bole.

PJ

== 4 of 12 ==
Date: Wed, Dec 17 2008 7:24 am
From: "Edward Frank"

Paul,

Yes you would need to calculate the center of the tree. We approximate this when we measure the base on a slope of when you measure the crown spread. It makes sense to measure from the surface of the trunk, but my problem with that is when a a tree forks and a branch takes off horizontally from the fork. Where do you start the measurement? At the point where it forks? At the point where the branch takes off form the fork? How many branchings back do you consider it to be the start of the limb? What about the idea of reiterations and how do they relate to limb length? How do you deal with trees that are leaning? A long lean in one direction could add twenty feet to the length in the direction of lean. So it is not as straight forward as you might think. Extrapolating to the center of the tree at its base would provide a relatively consistent reference point for all measurements and would be repeatable for everyone. The problem with leaning trees is that it would offset from the center of the trunk at the base.... The starting point of the limb could be considered at the surface of the trunk at say breast height, but that seems to be as arbitrary of a point as any other.

The last option,surface of the trunk at breast height, is the way I a leaning at the moment, with the "branching point" for leaning trees as the base point. Odd situations would need to be dealt with individually. So I am soliciting options form people who has thought out these situations. The way BVP is doing it may be the best way, I don't know at this point.

Ed

== 5 of 12 ==
Date: Wed, Dec 17 2008 7:41 am
From:

If a branch forks, it's still part of the branch. Where the branch starts at a fork in a trunk is possibly subjective, but so is breast height and the opinion of "where the acorn sprouted." Errors of a few inches one way or the other on a branch length of many feet typically end up being insignificant.

You have to decide what are you actually trying to measure. Is it the extent of horizontal tree growth relative to where the acorn sprouted, or is it the length of the piece of wood that is the branch which itself can be removed at that length by cutting, or is it the equivalent horizontal component of the length of such a branch? For a field measurement without climbing the tree, it would be easiest to measure the last one by choosing spots on the ground underneath, with a clinometer at 90 degrees and then measuring the distance between the marks, much as we do with the tree spread measurement.

By the way, the longest white pine branch that I recall seeing was on the order of 40-50 feet. It broke a few years ago during a storm event before I could return to measure it. A few other trees in that area have similar spreading form but haven't reached that magnitude yet.

PJ

== 6 of 12 ==
Date: Wed, Dec 17 2008 7:51 am
From: Miles Lowry

It seems to me that UNsupported limbs would be more helpful in
evaluating what the architecture of a tree could be rather than it
cosmetics (how's that for art-speak/)

miles lowry

== 7 of 12 ==
Date: Wed, Dec 17 2008 8:13 am
From: "Edward Frank"

Paul,

For me it is more of a "fun" measurement than anything else. I have no preference for how it is measured so long as it can be consistently done. If someone else finds the measure to be useful, and that utility requires some particular measuring protocol, that is fine with me, just tell me what it is. What do you suggest?

Bob indicated he had some ideas, so I am curious to see what he has to say.

Ed

Errors of a few inches one way or the other on a branch length of many feet typically end up being insignificant.

You have to decide what are you actually trying to measure.

== 8 of 12 ==
Date: Wed, Dec 17 2008 9:34 am
From: mdvaden

Your comment definitely introduces the reality check of comparing need
and want, or the possible and impossible.

Measuring to the center could be very unrealistic too, for trees that
naturally grafted codominent stems, or have very long limbs but
multiple leaders.

Even though the branch collar can prutrude to many lengths, I think
that the branch collar might be a sensible option from which to start.

XXXXXXXXXXXXXXXXX

Quote ...

"You'd have to measure to the trunk - it's the only aspect of the
length that you can actually MEASURE. How could you measure to the
center? You can't guess or calculate where it is. On many trees, the
center of the pith is very far from the geometric center of the bole.
>
> PJ
>

== 9 of 12 ==
Date: Wed, Dec 17 2008 11:45 am
From: "Edward Frank"

Mario,

In this case I might tend to agree that the branch collar is the place to measure. However I must strongly disagree that projecting to the center of the tree is unreasonable. Not only must you be able to to measure something, but there must be a common reference point so that when different people measure that aspect, they have an objective starting point. To get repeatable measurements taken by different individuals the subjective interpretation of where to begin must be minimized. The center of any reasonable regular object, such as a tree trunk can be reasonably approximated by different people and the variations between the approximations will be generally be small compared to whatever is being measured. The same is not true if everyone independently decides where to begin their measurements. If the tree trunk is approximately round then the distance from the trunk surface to the center is simply the girth/2pi.

If you are measuring the canopy spread of a tree you must include the width of the trunk in your measurements. The canopy does not stop and form an empty donut around the trunk. At the top of the tree the leaves extend over the area occupied by the base of the tree. So if the trunk dimensions are included in the canopy spread of the tree, then why should it not also be included in the measurement of individual branch length.

Branch length in this context I think should be measured in terms of horizontal offset from the innermost point to the outermost tip, rather than following the contorted path the branch takes to reach this outermost point. Using the branch collar as the starting point also eliminates the problems of leaning tree trunks.

Certainly where the "acorn sprouted" concept is more difficult to apply on larger western trees than it is with smaller eastern ones, but it is still valid. We have had this discussion before in ENTS and I argued for basic girth measurements to be made at breast height on the high side of the tree when it was on a slope. Ideally girth should be measured above basal flair, but there are practical considerations as well. Things that are hard to measure end up not being measured at all.

For the ENTS protocol the concept of the center of the tree is applied to a single trunk. For coppices or trees with co dominant stems, if the trunks have a separate pith at ground level they are considered to be separate trees for most measurement purposes. Thus the problem of where the center of the tree mass is simplified to the center of the particular trunk you are measuring. There are also criteria for characterizing multitrunk trees as a whole.

So the idea of extrapolating the center of a tree does not need a reality check, it is not unrealistic, nor is it impossible. The simplest measurement to make is not always the best, is not always the most repeatable, and not always the most useful for comparison purposes.

Ed Frank

== 10 of 12 ==
Date: Wed, Dec 17 2008 12:43 pm
From: dbhguru@comcast.net

Ed,

I've attempted to apply different concepts of limb length over the years. I'm fine with the extrapolated center point method. I'm also fine with locating the point beneath the limb flare as the starting point. That point can be fairly consistently identified on the vast majority of eastern trees, although a few pictures are needed to get the idea across.
One concept that I've experimented with a few times for limb length where an arching form adds considerable length is the parabolic length method. It is messy to compute, but more closely approximates the real length of the limb. An alternative is the slope distance of the limb via the Pathagorean Theorem. It is computationally much easier.
I will put together an attachment that illustrates the horizontal offset method, the Pathagorean method, and the parabolic arc method for a hypothetical limb. When they see it, I think most people will run from the latter with the exception of the scientists, engineers, and mathematicians. The parabolic arc method isn't practical for most field work. However, if we have a great tree with a long curving limb that would be greatly shortchanged were we to go with the horizontal offset, the parabolic arc method offers us an alternative.
It will take a little time to produce the attachment. I'm working with my wife's MAC and find myself hitting the wrong key about every other keystroke. It could drive a feller to drink.

Bob

== 12 of 12 ==
Date: Wed, Dec 17 2008 1:56 pm
From: Larry

Ed, ENTS, I think measuring the limbs of some of the larger trees is
way cool! I'll send in a couple of Live Oak measurements, and some
photos. I would measure from the point where the limb meets the
trunk. Larry

== 3 of 6 ==
Date: Wed, Dec 17 2008 5:50 pm
From: "Edward Frank"

ENTS,

Here is the initial Long Limb List awaiting your submissions.

http://www.nativetreesociety.org/fieldtrips/connecticut/pinchot_granby/pinchot_granby.htm
http://www.pabigtrees.com/trees/species/carya_hickory.htm
http://www.nativetreesociety.org/fieldtrips/penna_cook_forest/cook_9_6_05/cook_forest_9_6_05.htm

Edward Frank

Pecan Limb, 78' Length

== 4 of 6 ==
Date: Wed, Dec 17 2008 7:15 pm
From: "Will Blozan"

Bob,

It seems that the extant (straight line) of the limb would negate any
computation of "path length". All combined woody structures- be it a curve
or straight section- would yield the result of "x" limb extending "x"
distance in space.

Will F. Blozan
President, Eastern Native Tree Society
President, Appalachian Arborists, Inc.

== 5 of 6 ==
Date: Wed, Dec 17 2008 8:05 pm
From: "Edward Frank"

Perhaps both physical limb length as well as horizontal offset could be considered?

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