Bob,
What is the F value for the Coon Branch Pine? Will F. Blozan President, Eastern Native Tree Society President, Appalachian Arborists, Inc. _____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, November 11, 2008 5:27 PM To: [email protected] Cc: Rick VanDePoll; Sam Stoddard; Steve [EMAIL PROTECTED]; Laurie Sanders & Fred Morrison; David Govatski; Robert Carr Subject: [ENTS] Rejuvenated White Pine Lists and Volume Modeling ENTS The recent ENTS rendezvous in western Massachusetts has energized me to return to specialized big/tall tree lists. Beyond an interest in the knowledge encapsulated by the lists, my efforts are motivated by an awareness of informational gaps that need to be filled if the public is to understand and support our heritage big trees and stands of trees. In the case of the various white pine lists that Will Blozan, Dale Lutheringer, and I have conceived over the years, those lists are in recognition of the historic role of the white pine. This role especially applies to New England, but awareness of the history of the species has been diluted by a variety of fac tors, most of which work against preserving the impressive stands of white pine that we have remaining. In a nutshell, if people do not know what is significant or what will soon become significant, then preservation efforts will not likely be successful. To look backward in time, Pinus strobus was THE tree species in colonial New England. White pines were coveted for ship masts by the English monarchy and were widely used for construction purposes by the colonists. However, for a period of decades, the great whites lost most of their value due to the white pine weevil and the white pine blister rust, but the species has largely survived those threats and is still the eastern United States's tallest species. The white pine is definitely New England's flagship species for stature. Without it, our site Rucker Indexes would suffer greatly. In my humble view, because of its historical importance an d stature, the species deserves our respect beyond the mundane valuing of it for timber purposes. But for the public to value our heritage white pines, reliable information must be available on individual trees and stands of trees - information that has heretofore been very sparse. To acknowledge what has been done, there are a few New England sites that have been preserved because of their large and/or old white pines. Sites that come immediately to mind include the Bradford and Tamworth Pines in New Hampshire, the Carlisle Pines in Massachusetts, the Cathedral and Gold Pines in Connecticut, and the Scott Fisher Memorial and Cambridge Pines in Vermont. Exemplary sites such as MTSF, Ice Glen, and the Bryant Homestead, all in Massachusetts, escaped notice until recently. Now thanks to the ENTS website, masterfully created and maintained by our webmaste r Ed Frank, people who do Internet research can find dimension-based information and qualitative narratives on the white pine that put into context our beliefs about what may have grown in yesteryear as well as what is out there today. We are actively documenting white pine sites and gradually homing in on the genetic capabilities of the species across its geographical range. The latter mission has the greatest scientific value. I believe it is in our interest to expand our white pine database and organize it for convenient web-based maintenance and for general public access, but this mission will take time and needs our collective input. For the present, we can construct a list of important trees. To this end, I recently proposed to Will a criteria for inclusion of white pines in a list that for the present is aimed predominantly at the Northeast. He tentatively agreed. We would like the input from others. Basically, a pine would be included in the list if it meets any of the following criteria: 1. Is 150 feet tall or more (maybe less in northern New England), 2. Is 12 feet in circumference or more, 3. Earns 1500 ENTS points or more (ENTS Pts = girth^2 * height/10), 4. Has a modeled trunk volume of 500 cubic feet or more. These criteria are sufficiently strict in terms of what is growing now that the list, at least in the Northeast, isn't in danger of becoming so extensive as to give the idea that trees meeting any of the above criteria are everywhere common. That certainly is not the case and the point will need to be emphasized. The most difficult of the above criteria to apply is #4, the modeled trunk volume, which is the subject of the remainder of this email. Fortunately, there are shortcuts to allow us to approximate volume based on the general formula: V = F * A * H where A = area of the base at a designated height (such as 4.5 feet), H = full height of tree, and F = the form factor that lies between 0.333 and 0.50. For those who want to review the calculation of A, it can be done through any of the following formulas: A = PI * R^2 A = PI * D^2/4 A = C^2/(4 * PI) Where R is radius, D is diameter, and C is circumference (or girth). For forest-grown pines in the age-class of 150 years or more, the F factor will commonly be between 0.38 and 0.44. Stocky old-growth outlier pines may achieve a factor between 0.45 and 0.47. I doubt any pine will be 0.5, which is the factor that determines the paraboloid shape. The overall shape of a trunk of a mature pine characteristically begins as a neiloid (F=0.25), change to paraboloid (F=0.5), and then into a cone (F=0.333), but a single F value can be used to calculate the volume of a pine. Determining the value of F for a particular tree is our challenge. For initial inclusion of a pine in the list, the F factor can be estimated if a more exacting determination can't be made such as through use of the Macroscope 25/45. I acknowledge that a lot of work remains to be done on figuring out how to derive the F factor for a pine to get a quick volume approximation, but at this juncture, we are not helpless. We have a good head start. From data we've collected thus far, it is safe to assume all but the highly columnar pines will have a trunk volume that is less than the calculated value achieved by taking the cross-sectional area just above the root collar, the full height of the tree, and an F value of 0.333. By contrast, single-trunk old-growth specimens are proving to have volumes very close to the calculated volume using the base set at the root collar, with some trees requiring an F value as high as 0.35 or even 0.37. At the least, we presently have a strategy for homing in on the trunk volume by first surrounding it with high and low volume estimates. We then can refine the estimate by choosing an F value that appears to match the trunk. Judgment is involved, but with experience, we can eventually reduce the error to an acceptable level without being forced to fully model a tree. A fact obvious to me now that was not several years ago is that relatively few of us in ENTS are driven to calculate trunk volumes through full trunk modeling and do other kinds of tree modeling that is numerically intensive. So, if the few of us want volume-based lists created by more than just ourselves, we are going to have to come up with handy ways of calculating volumes that involve a minimum of calculations and that means refining the application of the F value. Today we are a lot closer to doing that than we were a couple of years ago. At this point, I feel confident in saying that for young pines, a straightforward trunk volume calculation using DBH, full height, and an F between 0.333 and 0.35 will give a close approximation for the junior class of pines. For old-growth specimens with straight trunks, DRH (R=root), full height, and an F between 0.30 and 0.40 will do the job in most cases. F values as low as 0.30 can be required where root flare is extreme and the tree tapers fast. For white pines of intermediate age, the volume calculation is equally challenging and we can approach it in several ways. Using BH (breast height), F can vary between 0.35 and 0.40. Using RH (root collar height), F will be between 0.30 and 0.36. Occasionally, the trunk will be so stocky that the F value for RH needs to be as high as 0.37, but that will not often occur on intermediate- aged pines. In general, the volume of a single-trunk, intermediate-aged white pine will usually lie between the two methods just described and often near the midway point. Let's now examine some specific trees. Jake Swamp Pine The average of the two volumes (CBH and CRH with F = 0.333) for the Jake Swamp tree is 574 cubes. This uses a CBH of 10.4 feet, which is what Will's model uses, as opposed to my more liberal 10.5 feet, Will's full modeling of Jake on November 1st yielded 573 cubes. This is an amazing match, and it is not accidental. The shape of Jake falls between that of young and old pines. Let us formalize these volume calculations. Let ABH = area of trunk at breast height, ARH = area of trunk at root collar height, H = full height of tree, F = form factor, VEI = volume estimate of intermediate-aged pine. VEI = F*H*(ABH + ARH)/2 Where F = 0.333 Tecumseh Pine Let's try the VEI formula on the Tecumseh Pine, an older, stockier tree, but not yet truly old growth. The circumference at the root collar is 13.24 feet and at breast height is 11.9 feet. The full height of the tree is 163 feet as determined by Will on his November 2nd climb. VEI = 693 cubes. Compared to the modeled volume of 779 cubes this is significantly low. However, the Tecumseh Tree is a stocky pine. Consequently, its volume can be better approximated by: VE = F*H*ARH, which yields 788 cubes and that is much closer. The F value for RH needed to reach the modeled volume is 0.35675, which falls between or 0.333 and 0.37 parameters. So, the volume estimation process works pretty well provided adjustments are made to the F value and the base area is calculated as either the lower, upper, or mid-point of collar to breast height span. I stress that the choices are dependent on the overall form of the tree. Saheda Pine As the last example, the Saheda Pine was modeled in 2007 by Will. It is comparably aged pine to Tecumseh Pine, but less stocky in its upper portion. Its measurements in 2007 were CBH = 11.8 feet, Height = 163.6 feet. Its girth at root flair, as determined by Will was CRH = 13.3 feet. Will modeled Saheda at 695 cubes. The RH volume is 767 cubes and its BH volume is 604 cubes. The average of the two is 685 cubes, which is close to the modeled volume of 695 cubes. The averaging method works for Saheda. The more slender upper portions of the Saheda Pine virtually guarantee that the RH volume will over-estimate the modeled volume. The greater age of the pine guarantees that the BH volume will under-estimate the modeled volume. The F value needed to produce the modeled volume using BH is 0.3835 . The F value needed at RH is 0.302. This latter value is necessitated because of the slender double trunk near the top of Saheda in combination with the root flare. Summary There is lots more to come on this topic along with lists of pines based on the proposed criteria, but to summarize. As a first cut, if the pine is young use: VEY = 0.333 * ABH * H. If the tree is a stocky old-growth specimen, use: VEO = 0.333 * ARH * H If the tree is intermediate in form and age, use: VEI = 0.333 * H * (ABH + ARH)/2 For a particular tree, as more measurements are taken, the F value can adjusted to better fit the observed form. Bob --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
