Tree Girth and Basal Measurements Edward Frank
  Nov 21, 2007

== 2 of 3 ==
Date: Wed, Nov 28 2007 11:24 pm

You've taken on a significant challenge, and made great headway!

Regarding measure of single-trunked trees, my thoughts follow:
It's a task that tradition has made simple, but has surprising complexity. Trying to keep to the simple solution, your concern for measuring those trees that aren't trees normally, but go beyond the shrub status that the plant displays in its 'young-growth' habit has brought you to suggest a 1.5 measuring height...I think, in the belief of establishing a standard like 'dbh' has become.

It occurs to me that perhaps one of the reasons (outside of, 'well, breast height is a convenient height to measure) that 'dbh' has become the standard was how effective it was as a height for measuring so many trees, above their butt swell.

TOPIC: Categorizing Tree Growth Habits

== 1 of 10 ==
Date: Thurs, Nov 29 2007 6:11 am
From: "Gary A. Beluzo"


Just a few random thoughts that I had:

I know WHY we measure CBH at 4.5 feet above the point on the ground
where the "acorn dropped"; it is a pragmatic method with economically-
based agenda so that folks cutting trees can determine lumber volume,
etc. But what does it tell us ecologically or biologically other than
the tree is "x feet around" at 4.5 feet?
Is it reasonable to measure ALL trees at 4.5 feet and make CBH the
standard ecologically? What about SEVERAL girth measurements done at
standard heights with standard methods?

ALso, what about a Girth taken at some % of the total height of the
tree? What would that tell us and would it be useful? I'll be playing
with some of these measurements over the next few months./

I am suggesting that since one of our primary objectives is to look at
trees ecologically, that we really should go back to square one and
think about what measurements make the most sense from an ENTS
perspective. We have better measuring tools now so that we can take a
number of measurements related to morphometry remote. So whyely, why
stick to the breast of some "forester meister" centuries back in
Germany (wipe that smirk off your face, Will and Bob!)? I think as a
scientific arm of ENTS we need to really think about what measurements
are important ECOLOGICALLY if we are going to redefine traditional
tree measurements (economically based, called mensuration) with tree
measurements that allow us to think about the tree in an ecological
way (I sugggested "dendromorphometry" 10 years ago to indicate our
methods would be based on ecological not economic considerations).
For example, in dendromorphometry it makes no sense to talk about
trees in terms of "sawlogs" or distances in "chains". These terms
have their place in forestry but not necessarily in forest ecology.
In any new discipline the "disciples" need to develop conceptual
frameworks, methods, and most importantly a clear and precise
vocabulary. I suggest we all think about what we ultimately want to
be able to do with the measurements we take and consider NEW METHODS
that we ought to be developing and promoting. Rucker Index is just
one example.

Obviously CBH, DBH, sawlogs, chains, and other forestry terms are very
useful to foresters but as a fledgling organization trying to promote
the ECOLOGICAL understanding and value of trees we need to rethink
some of these ideas and eventually codify them into what I have
suggested as "ECOLOGICS". Not only will we be moving toward a more
ecologically based understanding, modeling, and appreciation of trees
but also we can change the public image of people working in the forest.


== 4 of 10 ==
Date: Thurs, Nov 29 2007 7:28 am


I think that the premise that most DBH based volume measurement systems has
an economic consideration at its core is valid. When trees are measured for
timber purposes the form class (rate of taper) is based on the change in
diameter between 4.5 feet and 16.5 feet. On very good sites the form class can
be as high as 90 where the diameter of the tree at 16 feet is 90% of the
volume at 4.5 feet and I think that 4.5 feet was selected as a measurement point
because it is typically a point above the stump flare in most tree species.

As a relative comparison, in western Massachusetts it was common to use a
form class of 65 or 67 on hemlock trees with an "ice cream cone taper". Old
poplar in WV will often be tallied at FC 84 or 86

For comparison purposes a 20" DBH tree with 3 16 foot logs....about 50 feet
of wood has a volume of 256 board feet in International Log Rule FC 67 and 492
board feet in FC can make the cubic foot comparisons but they are
equally dramatic.

However, as many ENTS measurements have shown, older trees do not normally
taper as quickly as young trees and second growth trees.. this is probably as
much a factor of time as anything else.

But, I think that measuring trees at ground level incorporates far too many
potential errors. I have seen too many hardwood trees that had severed
stumps over 60" in diameter with an actual DBH of less than 30" to think that any
measurement scheme just based on stump or close to the ground diameter is
full of potential errors.

A system that you are working on that uses lasers and takes into account the
taper and diameter at various heights up the stem has significant merit. are in danger of coming up with measurement protocol that are much
more accurate than currently acceptable industry standards and to quote
Joe...I think real accuracy would bother the Holy Mother Church of stump worship.

Russ Richardson

== 7 of 10 ==
Date: Thurs, Nov 29 2007 12:07 pm

Don, ENTS,

I typed the last message in the middle of the night as I could not sleep. There was one point I wanted to make, but I guess I rambled around it. A classification system is simply a first step in organizing your information about a subject. It is not immutable and set in stone. As the knowledge of a subject changes the bounderies of you are studying, the categroies should adapt as well, to reflect new knowedge gained through the study process. These are my first pass categories.


I will think about what you have said concerning girth measurements. I think girth is an important measure. It may not be am ideal representation of size in every case, but it is a simple one to measure (generally) and is methologically unambiguous in almost every case. I don't see a better height at which to standardize the measurements. The position makes it easy to measure, so the measurement will be taken more often - that is a major consideration. It is above the basal flair of many trees, but not all, so that adds some irregularity to the data set.. Some trees flair noticeably outward at heights up to 30 or more feet - thinking bald cypress. Other trees reach heights only in the 20 to 40 foot range - witch hazel, dogwood, etc. So while 30 feet might be good for bald cypress, it would not be good for smaller trees. But there should be some single standard to facilitate comparisons between different trees.

Reducing the girth to a single measurement is problematic. However 4.5 feet is a reasonable compromise in my opinion, if a single measurement is what you want to do. It has the additional merit of having been a standard in use for decades or longer, and by maintaining this measurement point, even if we would opt for multiple measurements, it will allow us to make comparisons with a large body of existing data. Thanks for your input and ideas, they are worth considering.

Ed Frank

=== 9 of 10 ==
Date: Thurs, Nov 29 2007 1:56 pm
From: dbhguru

Ed, Gary, et al:

There is a point here that needs to be made, or maybe reinforced. I've made the point before, but am unsure what the rest of you think. While measuring girth at 4.5 feet above mid-base may be a good compromise, if all one is taking is one girth measurement, there is absolutely no reason why ENTS should feel restrained to limit our quantitative descriptions of the objects of our affection to a single girth measurement. Nor should we avoid taking a girth measurement at 4.5 feet for standardization and comparison purposes. We just need to think more broadly and avoid sliding back into a self-imposed limiting of ourselves for no good reason. Other organizations indiciduals should be following us, not the other way around.

Picking up on Gary's theme, the point is that we need to think about what other girth measurements we want to take and toward what purposes. After we've done a through job of anlyzing the possibilities, we need to develop a standard ENTS protocal to record measurements of important trees for posterity. On the girth question, from my viewpoint, we add considerable information about the tree by measuring the girth just above the root flare, wherever that is. Root flare and the subsequent taper is part of the tree. Folks, trees don't somehow become suddenly universally, across the board, comparable at 4.5 feet. That notion is manifestly absurd and always has been. It tends to gain credibility when trees of the same species and shape class are compared. Plantation trees fit the mold very well, but the live oak giants that Larry measures and dwarf trees don't. Very short trees such as the dwarf pitch pines growing on Mount Everett's summit need to be measured very close to the grou
nd. One foot is plenty high, if not too high. Eight inches would be about right on many of the trees. Perhaps a measurement at 0.75 and 1.5 feet to capture more of the taper.

I think it is time to develop a spreadsheet type layout of the kinds of measurements we want to take and toward what programs, objectives, or purposes. This would take us into entirely new and exciting directions. It would likely result in some new formulas and processes, but that is what ENTS and dendromorphometry is all about. In short, folks, we need to take the stuff we're doing seriously and not see it as peripheral to some simpler purpose such as supporting champion tree programs. We can, and should, do that, but there are far nobler objectives to pursue and ENTS is THE organization in the East to pursue them. Some will lead to formal scientific studies headed by folks like Drs. Lee Frelich, Don Bragg, Tom Diggins, and Professor Gary Beluzo. Others will be part of site or species documentations.

I plan to create a summary of all the formulas that I've been deluging the list with s of late . The summary will be in a spreadsheet layout. Hopefully, some of my fellow ENTS will then help me take this mathematical pursuit of tree architecture to new and glorious heights, identfying and prioritizing potential applications. I don't mind doing much of the theoretical development, but I would hate to see dendromorphometry languish or fall within the province of no more than 3 or 4 of us, with the remainder of the ENTS measurers limiting themselves to full tree height, girth at 4.5 feet, and some stab at average crown spread. Talk about a waste of talent.


== 10 of 10 ==
Date: Thurs, Nov 29 2007 2:33 pm

Hey, we've all got clinometers with us, so how about taking DBH and then bole angle at BH from a subjective but representative point at BH so that the taper can be inferred from the data table?
Paul J.

TOPIC: Categorizing Tree Growth Habits

== 1 of 11 ==
Date: Thurs, Nov 29 2007 4:50 pm
From: doug bidlack


I think that Ed has brought up a great topic and I've really enjoyed reading the responses. I basically
agree with what Ed has written regarding tree forms, but I mostly wanted to comment on tree measurement.

I've also had some problems with girth at 4.5'.  Here's an example: I go to a nice, open grown state
champion white oak and it is just a wonderfully symmetrical tree with no strange growths or very low
branching. Perfect. So I measure dbh at 4.5'. But then I come upon another state champion white oak with
a massive burl that greatly exaggerates the girth at 4.5' Then there is another with a giant limb
growing at 5' so that the girth at 4.5' is also way high. I don't really have a big problem with 4.5' as
the standard height for measuring girth for all the reasons that Ed mentioned, but you definitely cannot
measure the tree with the giant burl at 4.5' and say that that is an adequate comparison to the tree with
no burl. Same goes with the low branched tree...if you measure it at its smallest girth below the branch
(lets say it is 3') then you can't really compare this to the high branched tree measured at 4.5'. I have
been visiting many of the state champion white oaks, bur oaks and swamp white oaks. I eventually plan to
measure them all at the end of the same year. I was planning to take several girth measurements so that I
could estimate what the burl tree should measure at 4.5' if it didn't have the burl...or I could estimate
the cbh at 4.5' of the low branched tree. Then I could make better comparisons. Of course if one tree
is forest grown with little taper for quite a ways up I can't really compare this to an open grown tree
anyway. This will have to await some magical formulas from Bob so that I (or someone else) might be able to
come up with a good estimate of volume for each of these tree species regardless of their shape. This
will probably require a heck of a lot of measurements.

I think that for the time being, and probably well into the future, 4.5' should remain the standard. We
should be able to take measurements at other heights and then estimate what the girth would be at 4.5' on
an 'idealized' tree. With enough measurements, we might then be able to toss the 4.5' feet standard for
at least some trees, but this will take a long time.  I try to measure every tree that I've planted every
year. With some of the smaller trees I've begun measuring girth at a couple or more heights, but I
won't drop the 4.5' height for at least a decade or more. If I did, there would be no basis for
comparison with past measurements. That would be foolish in my opinion.


== 2 of 11 ==
Date: Thurs, Nov 29 2007 4:54 pm
From: dbhguru


We would have to take into account lean, if there is some, as well as taper. It could get tricky.


== 3 of 11 ==
Date: Thurs, Nov 29 2007 5:13 pm
From: "Will Blozan"


The method Jess and I use is the same as Colby's stick method- we just use a
clinometer instead. We identify "high side" ground first. This is the point
where the uppermost part of the trunk flair contacts the ground (below
litter layer). This elevation is transferred to the opposing side
(downslope) with a clinometer held with eye level the same as high side
ground. This spot is marked by an assistant and/or a thumbtack. Ideally it
should be transferred to a spot above "low side" ground. The distance from
low side ground (same as high side only on the low side) to the tack is
split in half. This is midslope, and all subsequent measurements are taken
in reference to this spot (likewise marked with a tack). The tack can be
left in "permanently" so the tree can be measured in the same spot the next

Note that the points of high side and low side ground are usually not
directly above each other in a vertical plane. This is not a problem since
dividing the distance in half will still be valid. However, when measuring
UP from the midslope the tape must be vertical- not on a slope. This can be
a pain on large trees so once midslope is identified the point can be
transferred via clinometer to a convenient side or the vertical difference
simply subtracted from 4.5 feet relative to high side ground. For example,
if the grade difference between high and low side is 32", then to measure at
DBH just subtract 16" (32"/2) from 54" (BH) above high side ground and find
that spot on the uphill side. Also note that we do not trace roots out- just
the lowest spot adjacent to the trunk.

I hope the diagram below makes it thru undistorted.


== 4 of 11 ==
Date: Thurs, Nov 29 2007 5:25 pm

My experience matches up well with Dougs...never in the years since I started working in the woods in the 60s did I encounter the perfectly symmetrical tree. They're like fingerprints, they're all different, and they're all similar. Similar enough that over a large population, one could eventually arrive at standards that stood up well to the population's diversity. I believe that to be one of the reasons why dbh is taken at 4.5 feet...that height across the whole population does well. Are there exceptions? Of course, it's not a perfect world and lord aren't we glad...Bob wouldn't have had such a character laden, humorous nickname, had perfectly conical trees been perfected through genetic modification...
There's a lot of resistance in the baseball world to recognizing Barry Bonds records with an asterisk, because sullies the records, and there are negative connotations...but could we not establish/accept a standard and then asterisk it, for further elaboration of measurement accuracy/inaccuracy/anomaly?

== 5 of 11 ==
Date: Thurs, Nov 29 2007 5:30 pm
From: dbhguru


If there is a burl at 4.5 feet, but clear trunk above and below, you could use an interpolated girth or diameter. For the benefit of all, I present the interpolation process below.


d1 = diameter at a point below the obstruction
d2 = diameter at a point above the obstruction
h0 = height (vertical distance) from d1 to d2
h1 = height (vertical distance) from d1 to obstruction
h2 = height (vertical distance) from obstruction to d2
d = interpolated diameter at obstruction


d = d1 - [(d1 - d2)/h0]*h1

This formula assumes that d1 > d2. If d2>d1 then

d = d2 - [(d2-d1)/h0]*h2


== 8 of 11 ==
Date: Thurs, Nov 29 2007 5:38 pm
From: dbhguru


Yes, we can develop multiple standards and asterisk the exceptions. That's the way to do it, so long as important measurements that don't fit the standard are not ignored in some mistaken belief that we can only record at the standard points. We now need to decide what we want to standardize. Ideas?


== 10 of 11 ==
Date: Thurs, Nov 29 2007 6:19 pm


There can be, and perhaps there should be, different methodologies for documenting an individual tree versus documenting a population of trees. I like the 4.5 feet standard as a fair approximation for looking at different populations of trees.


== 11 of 11 ==
Date: Thurs, Nov 29 2007 6:55 pm
From: "Gary A. Beluzo"

Doug, et al

This may be one reason why Bobby Leverett is so fixated on VOLUME. Volume may be the only reasonable way to compare whole trees quantitatively. Then the bulges and anomalous architecture doesn't matter...quantitatively. However, when we humans appreciate a tree visually there are certain dimensions that immediately speak "large" or "big" or "symmetry" to us and that is why I think ENTS needs to develop both quantitative and qualitative methods. What might the qualitative standards be? Well for starters how about a standardized way of presenting tree architecture with digital imagery?


TOPIC: Categorizing Tree Growth Habits

== 1 of 6 ==
Date: Fri, Nov 30 2007 5:29 am
From: "Gary A. Beluzo"

Good Morning Ed and other fellow Ents,

So, if you had no knowledge of the 4.5 feet standard, where and how would you compare the architecture of trees? Would you really start with a measurement at breast (whose breast anyway?) height? I only ask this because of ENTS is going to be the premiere group to whom others look to for methods of tree and forest ecology, I want to make sure we aren't making measurements a certain way because "that's the way it has always been done for forestry (agenda= economics). I am asking that we take a bold, independent, objective look at the methods that we have inherited.

This whole discussion is analogous to discussing religion with my neighbors. They try to proselytize me and when I try to have an open, non-judgemental, exploratory discussion with them they suddenly get VERY defensive; the religious dogma to which they have aligned their lives is immutable and non-evolving. I am not suggesting that that is happening here only that we should not stymie open, reasoned discourse about any of the methods we employ or concepts we accede to.

I guess I am bringing up this whole topic because when I read the "forestry" books I realize that many of the methods were developed specifically for assessing and improving the economic value of the forest. I think as a society we are moving beyond that limited perspective and perhaps it is time for a non-forestry group (myself and whomever else is coming from a purely ecological perspective (remember "silvics" and "ecologics") to take a fresh look at non-forestry assessment of forests and trees.

I am NOT suggesting that we need to throw out all of the traditional (remember they are specifically forestry oriented though) methods without consideration just to make up our own. This would be capricious and arrogant on our part. No, we need to have an open dialog from many perspectives including forestry and non-forestry paradigms.

Incidentally, I am using the limited capitalization for emphasis not to holler...if you can suggest a better way to emphasize words without the benefit of vocal inflection, please do. Perhaps we could use italics or bold?

Most humbly submitted,


Gary A. Beluzo
Professor of Environmental Science/GIS
Division of Science, Engineering, and Mathematics
Holyoke Community College
Holyoke, MA 01040

== 3 of 6 ==
Date: Fri, Nov 30 2007 6:59 am


Like I said before, I need to think about your ideas some more. You ask what height would I measure the girth if I did not know about the 4.5 feet standard. The problem is I do know abut it and am reluctant to throw out the data that has been collected at that height.

I don't think a single height would be definitive for measuring girth, but would opt for girths at several heights. I am sure that one of them would be close to 4.5 feet. These girth measurement heights are for the most part arbitrary, and so selecting a convenient measuring height would be reasonable among a series of arbitrary heights. I am still in the process of thinking about this, so I may change my opinion with more thought. Keep pushing for your ideas.


== 4 of 6 ==
Date: Fri, Nov 30 2007 7:31 am
From: Larry

ENTS, I think in my future Live Oak measurements, I will stay with
the 4.5' CBH standard, but I will also start measuring at ground
level. Live Oaks Trunks are often way larger above 4.5', on the
average most single trucked trees don't fork until 10-15'. So staying
with the standard in this case seems to me logical. However with the
Split trunks it is a different ball game. I really enjoy doing this
and we keep sending um' in. Larry

== 5 of 6 ==
Date: Fri, Nov 30 2007 7:53 am
From: Elisa Campbell

Hi all,
Gary asked about non-shouting methods for emphasis; how about asterisks
around the *word* or *words*? I believe it has worked for me and it is
(I hope) easily translatable for those getting digests ...

== 6 of 6 ==
Date: Fri, Nov 30 2007 7:57 am
From: "Gary A. Beluzo"


Sounds good, thank you.


TOPIC: Categorizing Tree Growth Habits

== 1 of 8 ==
Date: Fri, Nov 30 2007 8:57 am
From: doug bidlack


I completely agree. I really think that the American
Forests big tree system of points is just a quick and
dirty method of estimating volume. Maybe I'm wrong
about this. Anyway, we all know that it doesn't work
all that well. I'm very interested in what Bob and
others are doing in terms of modeling trees, but if it
takes a whole day to come up with a good estimate of
the volume of a single tree, will anyone use it? If I
wanted to know the total volume of sugar maples in the
Porcupine Mountains SP within one year, how would I do
this? We need different methods of measuring tree
volumes for different purposes.


== 2 of 8 ==
Date: Fri, Nov 30 2007 11:00 am

It's pretty clear that there are two different considerations, very accurate and precise measurement of exceptional (in every way) trees, or reasonably (economically reasonable, or as Gary might pen, eco-reasonable-nomics) accurately and precisely measured stands of trees.
It's also clear that to measure exceptional trees with just a D-tape and clinometer is not reasonable.
But from my perspective, it would be folly not to take a dbh/cbh while modeling a tree with hundreds of other measurements, an exercise in hubris, at I'll stand back, while I get flamed...;>}

== 3 of 8 ==
Date: Fri, Nov 30 2007 12:30 pm
From: dbhguru


You are right on target. We're working on highly detailed methods of modeling and also quick and dirty ones. There will be lots of species specific stuff, but it will be able to be applied quickly.


== 4 of 8 ==
Date: Fri, Nov 30 2007 12:35 pm
From: dbhguru


No risk of you getting flamed. If you all recall, I put forth a formula that works for young to mature white pine that uses 3 easy to take measurements: girth at just above the root collar, girth at 4.5 feet and full height. I'm working on both the detailed and the quick and dirty.


== 5 of 8 ==
Date: Fri, Nov 30 2007 2:04 pm
From: doug bidlack


Cool. I'm glad you're working on both. The reason I
brought up the 'porkies' is that I'm actually thinking
about taking off a month next year to measure trees up
there. I haven't run this idea by Ellen (my wife)
yet. As for my boss, he is actually for me taking off
a month...of unpaid leave that is. We are not hurting
financially and we don't have any kids, but Ellen
might not see it that way. I was thinking about using
the quickest possible method to get rough estimates on
tree size for each species first and then go back and
more accurately and precisely measure the contenders



== 6 of 8 ==
Date: Fri, Nov 30 2007 3:14 pm

Just a quick response to be followed up later...I know we've discussed this before, but maybe this is the time to formalize why cbh has to ENTS' ears, a more authentic ring then dbh? After all, no significant accuracy is lost using appropriate decimal representation of Pi...

Noting many photos taken of individuals taking the circumference, not all take the time to obtain accurate cbh's...whether a tree's "centerline" or pith line is a straight line or a curved line, the circumference should, IMNHO, be taken perpendicular to the line or 'chord', to be accurate...I liked the diagram Will put together to discribe how he determined where the h in cbh is taken...there should be somebody taking care that the D-tape is as accurately placed around the trees girth.
Gotta run, more later.

From: dbhguruTo: entstrees@googlegroups.comSubject: [ENTS] Re: Categorizing Tree Growth HabitsDate: Fri, 30 Nov 2007 01:30:14 +0000

If there is a burl at 4.5 feet, but clear trunk above and below, you could use an interpolated girth or diameter. For the benefit of all, I present the interpolation process below.


d1 = diameter at a point below the obstruction
d2 = diameter at a point above the obstruction
h0 = height (vertical distance) from d1 to d2
h1 = height (vertical distance) from d1 to obstruction
h2 = height (vertical distance) from obstruction to d2
d = interpolated diameter at obstruction


d = d1 - [(d1 - d2)/h0]*h1

This formula assumes that d1 > d2. If d2>d1 then

d = d2 - [(d2-d1)/h0]*h2


== 8 of 8 ==
Date: Fri, Nov 30 2007 3:46 pm


I want to address this question. Diameter is not used because a d-tape doesn't measure diameter. It measures the girth of the tree and divides it by pi. Unless the tree is perfectly round, then the d-tape gives a diameter does not represent the maximum diameter along the major axis of the tree, the minimum diameter along a minor axis of the tree, nor does it provide even the average diameter of typical tree. You get a value that all you can say for it is "this is the approximate diameter of the tree give or take 10 to 20% (or more)." By measuring the girth of a tree, you have a simple physical value - this is how big around the tree is. The tree is that big around, no matter its cross-section shape. By introducing the factor of pi into the diameter tape readings, you are making an interpretation, an assumption that the tree is round. That is simply not true. We do convert girths or diameters measured with a reticle to radii, and other values, with that hidden assumption
of roundness, but there is no good reason to incorporate that error into the simple tabulation of tree measurements. Girth is a physical measurement of a tree, while diameter is an approximate interpretation of that measurement.

Ed Frank

TOPIC: Categorizing Tree Growth Habits

== 1 of 16 ==
Date: Fri, Nov 30 2007 4:13 pm

I share your opinions!
"However, as many ENTS measurements have shown, older trees do not normally taper as quickly as young trees and second growth trees.. this is probably as much a factor of time as anything else"

I got to thinking about's true as long as you are considering the last addition of cambium. What do I mean? Say we're talking about a 275 year old sugar maple...that 275th layer of cambium DOES exhibit less taper than second-growth or younger trees. But does that same 275 year old sugar maple's 112th layer of cambium necessarily have less taper?

Or another way to ask this question...could it be that successive layerings of cambium, by the time you're talking several hundreds, 'average' the taper? If one were to take a fallen 275 year old maple, make successive 2 inch cookies out of the trunk, measure the distances accurately between rings, plot those distances on a graph, would that tree 112th growth ring graph out as having more or less taper than the exterior 275th one?

== 2 of 16 ==
Date: Fri, Nov 30 2007 4:24 pm


Hmmm...I think I could make a pretty good argument for the D-Tape "most" accurately measuring the "average diameter" for a more or less standard shape tree. But I see your point, circumference is circumference is circumference (or girth...:>)

But the very second that you do any mathematical operation to obtain area or volume with circumference, the conversion to diameter is implicit, is it not?


== 3 of 16 ==
Date: Fri, Nov 30 2007 4:36 pm

A few random thoughts follow...
While going back to square one, and looking at trees ecologically (which without getting too defensive,
I have done for years, even as a forester...;>), one of the first realizations is that they are part of the community, part of the ecosystem, and 'what part' needs to be one of the basic items to defined.
Presence, absence, and such descriptors certainly have their place, along with 3 dimensional considerations such as canopy and crown cover.
But size matters, if only to allude to the amount of space/sunlight/nutrition/etc. a plant takes up, out of the whole community. How we measure size can vary, but arithmetic formulas allow us to make judgments about the entire plant, that would otherwise be impractical to 100% sample/model all the plants. Most arithmetic formulas used for determining area involve circumference (and to add 'dimension' to that area, diameter). Diameter is not just an economics-driven measurement...


== 4 of 16 ==
Date: Fri, Nov 30 2007 4:42 pm

Just a quick random thought!
You're taking a lot of measurements, and a lot of care to obtain accurate volume determinations.
Of course that goes without saying...but by accepting dbh/cbh and the under 12 foot tree variation on that, for determining volume, are you not eliminating the very largest per lineal inch of height volume, which falls below these measurements (4.5 or 1.5 feet height)?

== 5 of 16 ==
Date: Fri, Nov 30 2007 4:44 pm
From: dbhguru


My research to date strongly supports the following model for young and mature (but not old growth) white and red pines and eastern hemlocks. Compute the average of the cross-sectional areas at root collar and at 4.5 feet. Take the full height of the tree. Calculate the trunk volume as that of a cone with the tree's full height and its base equal to average identified above. This can be reduced to taking the two girths and shooting the height with just a clinometer and putting the 3 measurements into an Excel spreadsheet. I could create the spreadsheet for you. The above formula applies fairly well to straight-trunked, narrow-crowned hardwoods. Old growth specimens are real mavericks and don't fit the mold. More research to do there.


== 6 of 16 ==
Date: Fri, Nov 30 2007 5:20 pm


Actually for any shape that is not perfectly round the area of the tree cross-section as outlined by the d-tape will be less than the area indicated by dividing the measured girth by 2 pi to obtain a radius and using the formula area = pi r^2 So a d-tape ALWAYS overestimates the effective or average diameter of the tree.

Yes you are correct that any time you do a conversion to cross-section area or volume the conversion is implicit. Bob and Will and the others doing volume measurements are wrestling with the problem of out of round trees - but again with the reticle they are measuring the actual diameter perpendicular to the line of vision rather than girth. In many trees the difference is not as great as 10% like I used in the example, but smaller. While in others that difference is close to the truth. Think of a ~9 ft diameter tree, one axis is 8 feet, the other axis is 10 feet. that is about 10% difference from the median value and 20% between the two extremes. This degree of being out of round is not uncommon. I don't know how to fix it.

== 9 of 16 ==
Date: Fri, Nov 30 2007 6:30 pm
From: dbhguru


The conversion to diameter is implicit unless you go for elliptical or some exotic form.


== 11 of 16 ==
Date: Fri, Nov 30 2007 6:37 pm
From: dbhguru


The initial fix that Will and I attempted to implement was that of an elliptical cross-section. Of course, the shape possibilities are endless, but at least having the elliptical option open put us one rung higher on the ladder.


== 13 of 16 ==
Date: Fri, Nov 30 2007 7:22 pm

there's a big tree on a steep hillside.
you're standing just uphill of it, with your feet on the lush moss covering it's roots, toes waggling up against what could be the root collar.
you've measured its circumference from your toes, up, every 6 inches, all the way to its tippytop, and modeled its volume with the satisfaction that you're within a tight range of error, due to the excess care you've taken, every step of the way.

did you measure what portion of the tree that lies below your toes? this would be visually a diagonal slice of the, hmmm, frustrum (?)

== 16 of 16 ==
Date: Fri, Nov 30 2007 7:40 pm

So given a set of trees whose cross-section is symmetrically paraboloid, a set of tree calipers would be more accurate measure of cross-sectional area than either the diameter or the girth (as measured by a D-tape)?

TOPIC: Categorizing Tree Growth Habits

== 1 of 12 ==
Date: Fri, Nov 30 2007 7:47 pm


Yes a series of diameters measured by calipers would do a better job than a tape for determining cross-sectional area.


== 2 of 12 ==
Date: Fri, Nov 30 2007 7:48 pm

But do either circumference nor girth provide you with a measure of 'ellipticality', any more accurately than does diameter?

== 3 of 12 ==
Date: Fri, Nov 30 2007 7:52 pm


I am not sure what exactly symmetrically paraboloid means... When they did the volume measurements on the Middleton Oak, and the giant trees Bob Van Pelt measure in the west. They do a detailed map of the footprint of the tree at the ground. This is similar to the calier concept. (If you were doing this you also would be measuring the volume of the wood on the lower side of a steep slope)


== 5 of 12 ==
Date: Fri, Nov 30 2007 7:59 pm

Last thought for the evening...I'm comfortable with use of circumference/girth versus diameter...just wasn't able to verbalize why ENTS chose to record circumference.
If the measure of a trees estimated diameter is needed, it can be calculated from circumference/girth.

== 6 of 12 ==
Date: Fri, Nov 30 2007 8:06 pm
From: dbhguru


No. We measure that diagonal slice separately as a part of some kind of frustum.


== 7 of 12 ==
Date: Fri, Nov 30 2007 8:10 pm
From: dbhguru


Do you mean symmetrically elliptical? If so, the answer would be that the calipers would do a better job.


== 8 of 12 ==
Date: Fri, Nov 30 2007 8:19 pm
From: dbhguru


We have to take two thickness measures 90 degrees a part. The cross-sectional area is:

A = pi*a*b if a and b are semi-major axes (half the thicknesss).


== 9 of 12 ==
Date: Fri, Nov 30 2007 8:25 pm
From: dbhguru


Circumference was chosen because it is used in the American Forests champion tree formula and because lots of people have a regular tape as opposed to a D-Tape. Conversion to diameter when needed was just a simple division by pi.


== 10 of 12 ==
Date: Fri, Nov 30 2007 9:09 pm
From: doug bidlack


That sounds great, but I must admit that I'm not
exactly sure about how to make the measurement at the
root collar.


== 11 of 12 ==
Date: Fri, Nov 30 2007 9:41 pm


I have been thinking about your question - essentially what would be the best process to measure trees in terms of ecologic importance. With regard to girth, I can't think of a good answer. Girth is a useful measure because it is unambiguous and does allow comparisons of size between trees. Cross-sectional area of trees in a given geographical area- say an acre provides information about stand density and distribution. Girth is a rough proxy along with height for volume - you know a fat tall tree has a large volume just by looking at it. So it serves as a kind of filter to decide what trees should be further documented. In a given area girth serves as proxy for age - in the same environment in the same area fatter trees are usually older than skinny trees. To me if you are going to reduce this parameter down to a single measurement - one that people will take - 4.5 feet seems as good of a point as any. Multiple measurements would be better, but...

What are you thinking about in terms of ecologic measurements? Even if your ideas are not fully developed we can discuss some specifics if I know, or other ENTS can have a glimpse of what you are thinking.

Ed Frank

== 12 of 12 ==
Date: Fri, Nov 30 2007 11:28 pm
From: dbhguru


The point is not precise, but can usually be seen as a point of inflection where curvature changes. It is not at the same height as one moves from tree to tree. Since this is an approximation of volume, you could standardize at around 1.75 feet to simplify matters on trees without a clear root collar.


TOPIC: Categorizing Tree Growth Habits
== 2 of 10 ==
Date: Sat, Dec 1 2007 5:42 am


I think that two things take place as the trees get older.

I do not think I have ever seen growth rings in the upper stem of a tree as
wide as the ones closest to the stump.

That being said, the growth of the upper stems tends to be incredibly
consistent and I really think that over a hundred years, or more depending upon
species, things average out to the point where the taper becomes minimal.

Once you get into really old versions of some of the longer lived species,
the last 50 years diameter growth can sometimes be completely identical at
stump height and 100 feet from the ground. I'm not certain but it seems that the
longer such growth characteristics persist the less significant twenty or
thirty years of rapid, juvenile growth can become.


== 3 of 10 ==
Date: Sat, Dec 1 2007 6:33 am
From: dbhguru


I have long recognized that the idealization of tree form to include circularity of trunk and the presumed paraboloid form for 16-ft log lengths has been for convenience and efficiency in the forestry world. But, the amount of error introduced by the need for efficiency varies significantly from very little to moderate and on occasion substantial. Though it is just my personal feeling, I think those at the professorial level believe that the errors, whatever their source, average out when large numbers of trees are involved. I have my doubts. I also believe that ordinary users of standard models and conventions forget, or are unaware of what trade-offs are being made. Lee Frelich once gave me an example of an outwardly appearing proper scientific study done by ecologists, I think, that used diameter as a predictor of tree height. Man, that is about as lame as it gets. I think the slipshod thinking of the authors made Lee a little ill.

Forestry and forest ecology alike take liberties and shortcuts when dealing with tree form. I would bet that in the majority of cases at the journey-man level the perpetrators are unaware of the sources and magnitudes of their errors. ENTS is going to begin addressing this unawareness. A study undertaken by Lee, Don Bragg, Will, and myself will quantify the error in measuring tree height that accrues from using only a clinomter and tape measure. The results will be partly species specific. I can tell you already that the magnitude of the error is correlated to closeness to the tree( short vs long baselines), tree age, growing conditions (open-growned vs forest shape), and species. For example, the error is minimal for many species of conifers that are young to mature. The unruly old growth forms result in more significant error. Some hardwood species result in significant error for open-grown forms. This study when complete will be the most thorough assessment of error as a product of the method of measurement.


== 4 of 10 ==
Date: Sat, Dec 1 2007 7:29 am
From: "Gary A. Beluzo"

Bob, Don and Ed,

I agree entirely with CBH. In limnology I calculate the Shoreline
Index which is comparing the perimeter of the lake ("dbh" would
definitely work with most lakes) to a lake with the same area but a
perfect circle. The equation yields an index which describes the
degree of shoreline development or development AWAY from a circle.
This has important implications for nutrient input, lake metabolism,
etc. So, I am wondering if this index would be a useful index to
ENTS, I think it might. (Bobby is going to love this, there are lots
of potential uses in volume and other modeling).

This would be the procedure:

Determine x-sectional area (A) of the tree at some height using Will's
framework method
Determine actual girth at that height (e.g. Girth at Breast Height)
with tape measure
Plug numbers in the following equation:

DD(4.5)i= GBH/2PiA


DD(4.5)i = Index of Dendricity (new term for ENTS) at height 4.5 feet
(but could be used at any height on the tree, maybe use at intervals?
GBH= Girth at Breast Height
Pi= Value for Pi
A= The actual x-sectional area of the tree at some height (in this
case 4.5 feet)

Essentially what the equation does is to compare the actual girth to a
calculated girth (circumference) of a perfect circle with equal area.
If the tree's x-section is a perfect circle then the DD(4.5)i would be 1
As the tree's x-section moves toward more and more dendricity the
index climbs.

Whatcha think Bobby?


== 5 of 10 ==
Date: Sat, Dec 1 2007 7:36 am
From: "Gary A. Beluzo"


I respect and value both your ecological and silvicultural
experience. And yes size does matter for many calculations and
considerations. If diameter is not "economically" driven then why was
it originally chosen since the actual empirical measurement is girth?
I suspect because it may be used to estimate the volume of potential
lumber, etc.
I am not suggesting that we leave all forestry measurements behind.
What I am suggesting is that ENTS as an ecological group consider what
measurements are useful for ecology and which are simply used because
loggers were the original folks making measurements in the forest and
no one has taken the time to examine these for the ecological utility.

Please understand that I am *not* putting down the forestry profession
for which I have great respect. But, we should all be open to
critical discussion of what we do and what we want to do.



== 6 of 10 ==
Date: Sat, Dec 1 2007 7:37 am
From: "Gary A. Beluzo"


I agree and that is why Bobby was proposing that we more carefully
consider the measurements below 4.5 feet.


== 7 of 10 ==
Date: Sat, Dec 1 2007 7:39 am
From: "Gary A. Beluzo"


Please consider my Index of Dendricity in an earlier email. This may
the beginning of a way out.


== 8 of 10 ==
Date: Sat, Dec 1 2007 7:40 am
From: "Gary A. Beluzo"

Ed and Don,

I think for practical purposes and especially for very large trees.
Will's frame method is probably the best way to go.


== 9 of 10 ==
Date: Sat, Dec 1 2007 8:14 am
From: "Will Blozan"


Here some examples of the frame mapping results of the Yonaguska hemlock.
The equivalent circumference is listed. Note the section at 73.25 feet above
the ground- over 65 inches across!


== 10 of 10 ==
Date: Sat, Dec 1 2007 9:42 am
From: "Gary A. Beluzo"

I'll play around with these in my Excel spreadsheet and GIS modeling
program. You are on to something here!


TOPIC: Categorizing Tree Growth Habits

== 1 of 15 ==
Date: Sat, Dec 1 2007 10:56 am


I think that there is no other way that will ever be developed that will
more accurately quantify size than volume measurements in cubic feet or cubic
meters. Height measurements aside the cubic foot volume is an amount we can
all personally touch and imagine and....cubuc foot volume does not have a major
function in forester.

that being said...form old time forestry lore I remember that although a
cord of wood cut and stacked up is 4'x4'x8' or 128 cubic feet. A cord in volume
is about 83 cubic feet of solid wood. A cord of wood is also determined to
be approximately 500 board feet... so...maiking a short story a little
longer...every time I read about a 1000 cubic foot tree I think about how much
error there can be when you take the air out of is almost 35%....but
imagining a 1000 cubic foot tree always tells me its a whopper.


== 2 of 15 ==
Date: Sat, Dec 1 2007 2:21 pm
From: dbhguru


Indeed 1000-ft cubers are huge trees. When they are conifers, 1000-cubers are special trees. When they are white pines, they are truly exceptional.

There are perhaps 3 giant sycamores in Western Massachusetts that exceed 2,000 cubes. The Sunderland Sycamore is probably around 2,500 cubes.


== 3 of 15 ==
Date: Sat, Dec 1 2007 7:40 pm

What, you don't wanna carry calipers capable of measuring 80-120" CBH trees into the woods?  I'm not familiar with Will's frame method...any descriptions already out there?
- BDon

== 4 of 15 ==
Date: Sat, Dec 1 2007 7:45 pm

The more measurements the merrier, especially when modeling...the question I've tried to ask unsuccessfully several times is "how is the 'stump part' measured, when on a side hill"? Per Will's diagram of a tree on the hill, it would be easy to assume that no measure is being made of the portion below the ground level on the upper side of the tree, yet that may be significant, within the context of desired accuracy...

== 5 of 15 ==
Date: Sat, Dec 1 2007 7:57 pm

Re diameter/economically driven, it may be even simpler than that...what measure of the tree do you see in two dimension (say in a photo of a tree)? It's the diameter you see...intrinsically you would estimate its diameter, and only after a rough calculation would you be able to estimate circumference, or girth from a distance.

As a timber marker (yes, I understand the economic aspect...;>), I got very good at estimating a tree's diameter (especially in the range of tree sizes I would normally encounter), and it would said of those like me, that they "had a good eye"...placing a tree in a 2 inch diameter class was easy...getting it less than 1" off, required more inspection and more experience, but we markers strove for that.

Re 'open mind', I'm all for it...I do have to say that it was hard not to feel set upon, or that "the old ways" were being thrown out, just for the sake of establishing a new clean jargon. From my perspective over the years and across different disciplines, I think there is way too much of that...but that just goes to show where I fit on the OF (old fart) continuum,,,:>}

== 6 of 15 ==
Date: Sat, Dec 1 2007 8:12 pm

I like your concept of 'dendricity', and it has widespread implications.
From a practical standpoint, the D-tape will provide you with a measure of the circumference (presuming a circular cross-section), and a D-tape will measure a tree with a shape is other than circle (and call it girth), but unless you perceive that the tree is out of round, you won't "know" the "how much out-of-round?".
Sorry to have such a hard time getting my mind around these fairly simple concepts...I had a hard time with 'basal area' too...;>)

== 7 of 15 ==
Date: Sat, Dec 1 2007 8:17 pm
From: James Parton

Don, Bob, Will,

In a simpler way I have wondered about this while doing CBH
measurements. When a tree is on a hillside & you are standing
downslope of it, like on a trail, where is it best to measure it?
From the downslope, or must you climb up behind the tree & measure it
there? It sounds like a lame question but when 4.5ft on one side of
the tree is further from the ground than the other side is, it makes
you wonder.

James Parton.

== 8 of 15 ==
Date: Sat, Dec 1 2007 8:26 pm
From: dbhguru


The only part of the tree we measure is the part that is visible. We can't measure what we can't see.


== 9 of 15 ==
Date: Sat, Dec 1 2007 8:28 pm

Three quick comment here...even more prone to poor prediction is the relationship between diameter and age...but that doesn't necessarily impart any particular evil to the measuring of 'diameter'.

Re 'liberties and shortcuts', that's absolutely economics in action...everything about measuring a forest (not a dozen large old-growth candidates) is labor (read dollars, effort) intensive and eats at what little margin there is (Joe and Mike certainly can identify here). ENTS members don't charge dollars for their labor of love, and take (from an economic perspective) inordinate amounts of time in their measurements.

Re height measurement study with clinometer and rag tape, foresters may measure total height for inventory purposes, but when getting ready for a timber sale, they are measuring from stump height to merchantible top (say 6" diameter, or whatever the contract says).

The part of me that spent decades 'being a forester' feels like you're throwing apples and oranges at me...;>} that is to say, there are major difference in objectives for the two disparate efforts...


== 11 of 15 ==
Date: Sat, Dec 1 2007 8:43 pm

I can't believe what a hard time I'm having getting my idea across. I'm referring to the portion (above ground) that you CAN see, when standing sidehill to a tree on a slope (make it steep to exaggerate).
In Will's diagram on 1.5 and 4.5 measuring points (from the proverbial acorn site), on the uphill side of the tree (where one might stand to measure the 4.5 H), do you model the tree portion that lies below your feet?-BDon

== 12 of 15 ==
Date: Sat, Dec 1 2007 8:45 pm

That is even more apparent when measuring very large trees on steep slopes...many times you CAN'T measure from the bottom, can't even raise it up to a level taping without long sticks, etc.!

== 13 of 15 ==
Date: Sat, Dec 1 2007 10:05 pm
From: dbhguru

Don and Gary,

I'd like to weigh in here if you all will permit me. Don, part of the challenge of seeing the whole through the profile of the tree is that that the profile changes as one circles the tree. So, to do it right, we really do need multiple measurements taken from different vantage points - very labor intensive to say the least. Old fashioned calipers have their place, but practically speaking, they can only be used near the base of the tree unless one is a climber. However, enter new technology. Bole thickness is what we measure now with the Macroscope 25 and 45. When we use a Macroscope, we measure from a distance the thickness of the bole up as far as we can see. We dispense entirely with girth measurements. All of my detailed modelings use either the Criterion RD1000 Dendrometer-Relascope or one of the two Macroscopes mentioned above. I own one of each.

Now to a critical point that I don't often address. By: (1) taking a girth, treating it as the circumference of a circle, and calculating the equivalent diameter, or (2) by measuring bole thickness and treating it as the diameter of a circle, either way, we arrive at A = pi*D^2/4 as the means of calculating cross-sectional area. Modeling on this basis, we almost always overstate the actual trunk volume. This occurs because a fundamental property of the circle is that it maximizes cross-sectional area for any specific perimeter. Whether the overstatement averages more than a percent or two is the big question.

I have thought about tracing stump perimeters with tracing paper and figuring out the enclosed areas and comparing them with circles based on perimeter measurements from the tracings. I'd like to get a feel for how much on the average we overstate volumes and what the measure of dispersion would be. I'm thinking that taking digital images of the tops od stumps and running the images through sophisticated software programs would be the high tech solution to computing cross-sectional area. It is a project on the long. long docket.

Now to a potentially contentious point. Don, I don't think that Gary wants to throw the old ways out just for the sake of being different. It is just that standard forestry procedures and calculations don't address the problems we're interested in solving. They address different problems and that's okay.But in perusing the pages of my text on forest mensuration, I have found nothing that would suffice to allow us to satisfactorily calculate the volume of a trunk of one of the big trees we've modeled and certainly not the combination of trunk and limbs. Years ago we saw the problem we faced and were forced to pioneer a new method. Will Blozan responded by climbing Yonaguska. We've been on a modeling tear ever since.

If we were forced to innovate on volume modeling, we were forced to innovate even earlier in order to measure full tree height more accurately. Being within 10 or 15 feet of the actual tree height was not good enough for us. How did we know we were making such errors? Well, after making some very embarrassing errors in the early 1990s by using a clinometer and baseline, I was forced to realize that I had to go to the drawing board and figure out what was going wrong. Transit measurements by Jack Sobon and myself had left no doubt that the clinometer and baseline method could lead to significant error made by amateur and expert alike. The result of atoning for my measuring sins was the birth of sine-based mathematics. Yes, that is how it all began. I had to dispense with orthodoxy and think like the mathematician that I am.

In terms of existing language surrounding our tree research, for the most part, forestry is log-focused and of course, for good reason. But, as you know, seeing trees as timber isn't where ENTS focuses its efforts. We are full tree focused for pure research purposes. Now, I'm not saying that part of forestry doesn't look beyond log lengths, but for the most part forestry does reduce trees to commercial log lengths. Tree plantations illustrate the degree to which trees have been coaxed into a timber-associated conformity. However, if existing forestry methods work for us, we should have no hesitation in using them. I would hope that we would never get snobbish and reject thoroughly tested methods just because they were developed around a commercial purpose.

On the jargon end, our Internet banter not withstanding, our introductions to date have been wholly to name new processes and methods, e.g. Rucker Site Indexing that has no forestry counterpart that I know of. Do we need to take naming further? Well, let's see what Gary has in mind. I'm for entertaining new concepts so long as we agree to drop them if they don't prove efficacious. This having been said, I would be disingenuous if I didn't acknowledge that there is something lurking in the shadows. If Gary wants to go further in renaming, I think it would be partly because he objects to the saturation of the field by economically-driven thinking. The thinking has been so pervasive that it has reduced trees as organisms to a small fraction of what they really are and the many complex roles that they play in ecosystem maintenance. I don't want to put words in his mouth, but I think Gary sees current forestry language as having solidified around the over-arching concept of trees
as timber. But with canopy research now going on, new language is being introduced. The winds of change or blowing. Life in the canopy and the complexity of old growth specimens is taking us in a new direction that sees trees far more holistically. I'd be curious to see all the new terms that BVP and Steve Sillett use now. That makes me all the more curious to see what Gary has in mind for us.


== 15 of 15 ==
Date: Sat, Dec 1 2007 10:10 pm
From: dbhguru


Yes, we model that part as a wedge. We've discussed the process in the past, though sparingly. You were off list for long periods and most likely missed much of those discussions. But, yes, we do model those downhill parts as best we can.


TOPIC: Categorizing Tree Growth Habits

== 1 of 1 ==
Date: Sun, Dec 2 2007 7:19 pm

I penned a response that I've since deleted, as I reread your post...question - When you model with the Macroscope, are you taking diameters at ninety degrees? Perhaps after you perceive what may be the broadest or narrowest measures (takes good judgment)? At each segment of the tree?

TOPIC: Categorizing Tree Growth Habits

== 1 of 5 ==
Date: Mon, Dec 3 2007 6:04 am
From: "Will Blozan"

How? Jess and I frame-mapped a few hemlock bases but don't use it regularly
for several reasons. I'll post a bit on it later.


== 2 of 5 ==
Date: Mon, Dec 3 2007 7:06 am
From: "Will Blozan"


In the Tsuga Search Project Jess Riddle and I made a decision as to how to
deal with the bases of the trees. I will call this portion the "basal
wedge"; a level, more or less circular cross-section on the "top" with a
neloid flare short in length on the upper slope portion and much longer as
it descends the slope.

In the field Jess and I would make a subjective decision as to what the
lowest measurable point was (LMP). This point was selected based on several
reasons and assumptions:

1) that point was relatively undistorted with regard to trunk flare and
"out-of-round-ness" (is the term dendricity?)

2) that point represented a logical transition from the above portions and
taper of the trunk (i.e. not radically wider than the previously measured

3) that point - as best we could tell- would represent a surrogate amount of
wood for use in subsequent calculations of the "basal wedge"

4) note: LMP could be any distance above the ground; on some of our trees we
used a point at or above BH.

Yes, it is all subjective, but the next step was simply to calculate the
volume of a cylinder with the length of the distance from LMP to midslope
(1/2 the vertical grade difference from high side ground to low side

The decision to use this short cut was based on several reasons, one of
which was economically driven. Since I was funding most of the Tsuga Search
Project out-of-pocket I simply couldn't afford the added weeks to measure
the basal wedges in detail. This decision was made much easier by actual
field trials Jess and I performed to substantiate that the short cut was
"OK" to use. Most profound was the finding that the difference in the volume
you get by spending several hours frame-mapping a base (the only way to do
it) on steep slopes in rhododendron and Leucothöe slicks for a few cubes of
wood made no sense. Basically, we would spend hours and hours to gain a
miniscule amount of accuracy. In our trials some trees "gained" a bit of
wood, others "lost" wood relative to the short-cut method, but either way,
it was a small percentage of the total volume of the tree. Also, the intense
detail of the lower few feet was not repeated in the upper 140-170'. And
because I know your wondering, the frame-mapping was done as in the tree
(incrementally from LMP to a small section at low side ground) but the
ground intercept formed the "end" of the wood measured. The "slices" were
then converted to circular equivalent and modeled as frustum of cones. Here
are some examples:

Although not perfect, the short-cut does seem to work fairly well based on
our limited sample of frame-mapped trees. We could do more exhaustive
testing but for our tiny eastern trees, it does not seem worth it. This is
not to say that other trees couldn't seriously benefit from a careful frame
mapping of non-conforming trunk flare. I would really like to know the
actual diameter of the Cat Island baldcypress!

Just for the record, as far as I am aware, this is how the volumes for ALL
trees listed by ENTS have been measured (except the Middleton Oak).


== 3 of 5 ==
Date: Mon, Dec 3 2007 11:37 am

Again, exemplary work you've undertaken, and wonderfully diagrammed. Hopefully you're heretofore unheralded efforts will soon make the progress you seek!
Your balance between accuracy and time spent acquiring it seems appropriate. Short of creating some kind of 'foam mold' and determining how much volume it would take to fill (and that would be unreasonable for many reasons), I can't imagine a better way. Keep up the good work!

== 4 of 5 ==
Date: Mon, Dec 3 2007 7:27 pm
From: John Eichholz

Russ, Gary, et. al.,

I like that reasoning. A 1,000 cubic foot tree -- that must be at least
10,000 board feet! I remember once we figured there was about 25,000
board feet of wood in the houses we built when I was a carpenter. That
must be quite a few "regular" trees.

Also, when I split wood for the cook stove and carefully stack it, I
seem to get about a 25% - 35% volume increase over solid wood, but I
imagine the 83 to 128 cubic foot expansion could be true starting with
log length.

Speaking of quick and dirty, if you square the girth in feet, then
divide the result by 12, you have a close estimate of cross-sectional
area in square feet that can be figured in your head. Also, if you
square the diameter (in feet) of 16" length wood you get approximately
the volume in cubic feet. (pi/4 * 4/3 ~= 1)

Another musing from the wood pile: A 6" diameter piece of wood has
almost 50% more wood than a 5" diameter piece. Lets see. If we let the
tree grow another 3 years at 6 rings per inch, we get 50% more wood?
Probably not, but every time I look into it, the tree is increasing in
value at a respectable rate, at least from a raw material basis.

On the other hand, I might not be the quickest at getting in wood.

John Eichholz

== 5 of 5 ==
Date: Mon, Dec 3 2007 9:50 pm

Nearly correct...12 board feet equals 1 cubic foot. 1,000 cubic feet equals 12,000 board feet...minus some saw kerf (let some of our field foresters come up with saw kerf loss...;>).