And, of course, the technique was invented by Archimides: http://en.wikipedia.org/wiki/Eureka_(word) Not for logs, but for anything.
Joe On Sep 28, 7:49 pm, [EMAIL PROTECTED] wrote: > Bob/Joe-- > > The water displacement technique for measuring log volume has already been > described in research papers--one such paper was recently published in the > Southern Journal of Applied Forestry. You can find the abstract of this > article > at: http://saf.publisher.ingentaconnect.com/search/article?title=volume+m...(unfortunately, > you need a subscription to get the full article). The unique aspect of this > work is that the author took detailed measurements of logs and then > translated them so that a computer-controlled system (often used to create > miniaturized plastic models) made small versions of the logs to displace, so > the large bole wouldn't have to be put into an Olympic-sized swimming pool to > displace the water. > > Definitely a technique to highlight in the Dendromorphometry book... > > Don > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Don C. Bragg, Ph.D. > Research Forester > USDA Forest Service > Southern Research Station > [EMAIL PROTECTED] > ~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > The opinions expressed in this message are my own, and not necessarily those > of the Southern Research Station, the Forest Service, or the USDA. > > > > -----Original Message----- > From: [EMAIL PROTECTED] > To: [email protected] > Sent: Sat, 27 Sep 2008 6:35 pm > Subject: [ENTS] Re: Sneak preview > > Joe, > > > > The water displacement process can be used in a piecemeal way to test the > closeness of different formulas. Over the years, I've discussed water > displacement as the litmus test of volume20in emails. The big question for > the analyst to ANSWER is how far does the volume of a log or section of trunk > or limb differ from the frustum volumes of the more common regular > geometrical solids. The frustum formula: > > > > V = Pi*F*H*[a^2 + b^2+ a*b] > > > > where F = (1/4) for a neiloid, (1/3) for a cone, and (1/2) for a > paraboloid and a and b are the radii at the ends of the frustum is the one we > apply most commonly these days. The formula assumes a cross-sectional area > that is circular. However, the formula can be modified if the cross-sectional > shape is more elliptical. In this case we would need to use the semi-major > and minor axis from each end of the frustum. The formula would look like the > following: > > > > V = Pi*F*H*[a1*b1 + a2*b2+ SQRT(a1*a2*b1*b2)] > > > > The utility of these formulas is their repeated application. We break > long lengths into series of short sections. In the aboev formulas, H should > not be high or too many changes in trunk shaape can be obscured. > > In trees that Will Blozan has climbed and modeled (he's done by far the > most in the eastern United States), his frustum height are often a meter. He > climbs the trees to get girth measurements ever meter of height. In addition, > he fr > ame maps trunk splits by using a highly accurate method we developed in ENTS > to determine cross-sectional area. We don't just assume circularity or > ellipticality where that is obviously not the case. > > Before leaving the subject I note that log volume charts commonly > employed by foresters are of no value to us. They may too many simplifying > assumptions. I started out with them years ago, and while they may work for > large numbers of logs, I found them to miss individual trees, especially > large, old ones. So from that point one Will and I went it alone. > > All this will be covered in the book on Dendromorphometry > that Drs. Frelich and Bragg and Will Blozan and myself plan to write. It is > supposed to be under way at this point, I because of my medical situation, I > needed time off before taking the plunge. However, when the book is > eventually completed, it will include many methods for volume modeling - on a > poor man's budget. That will leave plenty of room for high tech wizardry in > the future, some of which is already being developed and employed by the > likes of Drs. Steve Sillett and Robert Van Pelt in Washington. > > > > Bob > > -------------- Original message -------------- > From: the Forestmeister <[EMAIL PROTECTED]> > > > BTW, a suggestion- to check how accurate current methods are for > > measuring the volume of large trees- I suggest going to a forest that > > is about to be logged- no doubt you can=2 > 0find some really big trees- > > then measure them- then when that tree is cut, it should be easy to > > gather all the crown, in pieces and measure the volume of them by > > placing in a tank filled with water (specially designed of course) > > whereupon the displacement of the water would give an accuratge > > measurement- and the cut logs could easily be measured extremely > > accurately before haulded off to the mill. The actual physical measure > > by this method should be extremely accurate- then compare that to > > various methods now be ing considered (of which I know nothing other > > than rough measurements for merchantable logs). > > > Joe > > > On Sep 27, 4:09 pm, the Forestmeister wrote: > > > Well, I don't know what the accuracy of current methods are when > > > estimating tree volumes but it's not likely to be more than plus or > > > minus 10% if you're including all the crown. With a digitilized scan > > > done by my the technique I'm fantasizing about - I should think it > > > would be accurate to plus or minus a tenth of a percent which would be > > > orders of magnitude better. > > > > Regardless of that issue- I think it's urgent for us to start putting > > > real dollar signs on all the currently intangible values- which are > > > more likely to be significant for large trees- the larger the trees, > > > the greater for those intangible values. Though there ma y not yet be > > > market values for these considerations- if we > pretend that there are- > > > maybe they'll happen. > > > > For example, let's say we do come up with a value system- then say, > > > the state wants to buy a property to add to an existing state forest/ > > > park- when they negotiate with the owner they should have to factor in > > > such values- because we'll all demand it. After all, when people > > > appraise something like antiques- there is no logic to it other than > > > supply and demand. If a landowner were told that the value of their > > > property was something beyond what some real estate appraisser says- > > > then it will be so if they believe it. Much of our economic system is > > > "faith based", not logical- so we must all have faith in the true > > > values of large trees and old growth forests, c'est nes pas? > > > > Joe < BR>> > > > > On Sep 27, 10:50 am, "Will Blozan" wrote: > > > > > Joe, > > > > > What do you mean by "orders of magnitude"? That would imply at least ten > > > > times more accuracy, but in what units? > > > > > Will F. Blozan > > > > President, Eastern Native Tree Society > > > > President, Appalachian Arborists, Inc. > > > > > -----Original Message----- > > > > From: [email protected] [mailto:[EMAIL PROTECTED] On > > > > Behalf Of the Forestmeister > > > > Sent: Friday, September 26, 2008 3:58 PM > > > > To: ENTSTrees > > > > Subject: [ENTS] Re: Sneak preview > > > Hey Bob, I know next to nothing about the sophisticated methods ENTS > > > > people use to determine tree vol umes- I only know standard, basic, > > > > simple methods of tree measurements used by field foresters. But, I > > > > should think that there must be some way using the best technology in > > > > the world today to get an exact 3 dimensional image of any tree- using > > > > something like radar or some other electromagnetic radiation- by > > > > moving the energy generator AROUND the tree- sort of like a giant scan > > > > of a hospital patient. > > > > > The scan could scan the shape to great detail in 3-D, then incorporate > > > > that into data into a holograph in order to project it- and I'm sure > > > > mathematical geniuses could easily then use that data to calculate the > > > > volume of the tree to an order of accuracy orders of magnitude beyond > > > > current ENTS methods. > > > > > And, while at it, why not use pene trating energies such as the > > > > hospital scan to give a true internal image of the tree which could > > > > then be studied for whatever reasons, such as the work done by Alex > > > > Shigo to determine the course of "discoloration and decay"- or to > > > > discern the value of the tree for wildlife habitat (assuming some > > > > hollows in the tree). > > > > > And, if this is done for many trees close together- it could be useful > > > > to Gary Beluzo who I reca > ll is interested in the emergent properties > > > > existing in forests- and for that, having such information and > > > > modeling tools- might be significant in such research. > > > > > Just a crazy thought. > > > > > Joe > > > > > On Sep 25, 9:06 am, [EMAIL PROTECTED] wrote: > > > > > Beth, > > > > & gt; > The proposed ENTS point formula admittedly works best for trees > > > with > > > > long straight trunks that can be modeled with a regular geometrical > > > > form, > > > > principally a neiloid, cone, or paraboloid. I chose the cone for > > > > illustration purposes, but either of the other two forms would have > > > > worked > > > > just as well. > > > > > The question of what kind of formula works for a big spreader like > > > > the live oaks that Larry measures is probably not going to be adequately > > > > determined for a long time. There is just too much wood tied up in the > > > > complex network of limbs. The ENTSPTS formula is not the answer for > > > > trees of > > > > that shape, but then neither is the champion tree formula. Consider the > > > > table below. > > > > > > HGT CIR SPD CHP PTS ENTSPTS > > > > > 50 12 12022472 > > > > ; > 6 524120383374.4 > > > > > 13024120448748.8 > > ... > > read more »- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org You are subscribed to the Google Groups "ENTSTrees" group. To post to this group, send email to [email protected] To unsubscribe send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/entstrees?hl=en -~----------~----~----~----~------~----~------~--~---
