Mismeasured Trees    Edward Frank
   Sep 12, 2005 15:07 PDT 
Mismeasured Trees

I want to elaborate some more on what I am trying to accomplish with a listing of mismeasured trees. Will Blozan has clearly and concisely explained the mechanics and mathematics of different tree measuring methodologies in his essay:

Tree Measuring Guidelines of the Eastern Native Tree Society

To my mind there are two areas that still need to be addressed to complete the picture. First there is a need to demonstrate by example that the tree heights generated by baseline methods and the the tree heights measured using the ENTS laser Rangefinder based methods have different results. The other part that needs to be demonstrated by example, not just conceptually, is that the ENTS techniques measure the true height of a tree accurately. This can be shown by developing a table of trees first measured using the laser rangefinder/clinometer to determine a height, and then were climbed and physically measured. Will Blozan, Bob Van Pelt, Michael Davie and others have measured and climbed numerous trees and the information only needs to be compiled to generate this table.

I wrote previously concerning the table of mismeasured trees:

There are numerous mismeasured trees out there. I want to concentrate on trees that have made some sort of a formal list, state, national, university big tree lists. I will tabulate all of the mis-measured trees sent to me, but want to focus on those examples.

Trees do not need to be native. I would like to get the following information IF AVAILABLE for any significantly mismeasured trees:

Species (common name / also scientific if it is unclear which species is under discussion)
Original Height Measurement
Source or erroneous listing- for example: national champion list, state champion list, university list, publication, etc (with date of publication)
ENTS measurement
ENTS measurer and date
Specific location - to at least state if not county or town or park
Tree Name if it is a famous or named tree
Comments - any additional relevant information

For compilation purposes I will compile information that is submitted. If the final product is to used for scientific demonstration purposes there must be a different final list criteria. The business of science requires documentation. If a tree is to be shown as having been listed with an incorrect height, we must have specific information on where and when it was listed and by whom. If we do not have this listing information, the tree can not be used for demonstration purposes.

For example in a post today Will Blozan listed errors in the NC State 2005 champion tree list for Bur Oak and Katsura. These listings have been personally confirmed by me by accessing the NC Champion Tree list online. For the older listing of white oak he also submitted, that can be compiled, but not used in a demonstration list without specific list information. The current NC Champion Tree list has no entries for white oak. I will try need to confirm, or have a specific reference for any reported mismeasured tree height for inclusion on a demonstration list. If we are to be taken seriously, we need to have a listing that contains no mistakes in listing height derived from other sources. We need to be able to document the source these erroneous height listings. This may be a pain, but there is no way around it if we want to do things right - and I think we want to do things right.

Ed Frank
Re: Mismeasured Trees    abi-@u.washington.edu
   Sep 13, 2005 02:27 PDT 


I would encourage everyone to help Ed with this project.

This is an extremely important issue that no pre-ENTS organization was ever able to accomplish. For that matter, even ENTS has only become capable of doing something like this fairly recently.

As a student of writings about trees, including very old books, it becomes obvious how errors propagate. We, who produce measurements of trees, are continually PLAUGED by historical measurements. Just because a book is OLD or REALLY BIG does not mean the data sources are all carefully garnered. We know the AF list of national trees is filled with errors, and we now see how many of these errors arose. Yet this flawed work is FAR more interested in being accurate than some taxonomist writing a scholarly book back sometime in the 19th century. Yet when one of these numbers is published it is IMPOSSIBLE to get rid of. Proof is something that time erases - so we just have to live with that - but here we have an opportunity to at least make it clear that historic numbers may not always be what they seem.

Sure, we are dealing with table scraps from the great forests of old - both on the East and West Coasts. But I must say that I now view statements about how the forests were MUCH taller in the past with a certain amount of skepticism.

ENTS and others have made some amazing discoveries - several TALLEST EVER RECORDED trees were found both on the East and West Coasts leading me to believe that our tablescraps may not be so pathetic.

Anyway - Thanks Ed, and let's make this happen!


Bob Van Pelt

Re: Mismeasured Trees

I want to point out that while many of the mismeasured trees appear in the American Forest lists, American Forest does not guarantee the accuracy of the measurements.  Will Fell wrote:  "You are crediting the AF register for the mistaken measurement, when the AF only lists one tree (or maybe two if co-champions) of each species...Also the AF does not actually measure trees, they just maintain the register. They only report what was submitted to them from the state coordinators. So any mis-measurements would be from the state or in some cases private parties that make nominations directly."

Will Fell is the State Tree Coordinator for Georgia.  He wrote on Sept 13, 2005:  "As a state coordinator I would like as accurate list as possible, but we do have a philosophical difference about how far to carry this in expense, time and equipment. The champion tree/big tree registers are not intended to be a scientific document. They are a “popular” program intended to draw attention to our large trees and as such the idea is to include as many folks as possible, not to exclude all but a handful of purists with the training, time and equipment to obtain the level of accuracy desired on the ENTS list. Please I am not disparaging y’all, I am all for what is being accomplished by ENTS, but to demand the level of accuracy only obtainable with pricey lasers and range finders will kill the big tree program in many states and exclude the very people we need to be reaching….the general public."

"There is no excuse (other than accepting sloppy measurements) for differences of 10-50 feet as you have shown on big tree lists but I will still argue with you that properly used (w/ perhaps a touch of Kentucky windage) a clinometer will provide an acceptable level of accuracy for the purpose of the big tree program for most trees. The limitations are on the operator such as not taking the time to do it right or being unable to go out far enough to measure the high point of a broad crown or make a good estimate of the location of the high point in the crown."

I am not debating whether or not the accuracy reflected in the American Forest lists are sufficient for to be useful to the general public, or used to create interest among members of the general public. That is not why I want to compile the list of mismeasured trees and is another argument entirely.   The purpose of the list of mismeasured trees is to demonstrate that in field usage the ENTS techniques provide more accurate and consistent results than do forestry clinometer and tape techniques, and that these laser techniques are not subject to some of the errors outlined in Will Blozan's Tree Measuring Guidelines document. There are many examples of grossly erroneous measurements that have appeared in one publication or another. Will Fell has argued that these grossly inaccurate measurements are a result of improperly applying these basic forestry techniques and with proper usage, better and reasonably accurate measurements can be made. That idea that better measurements could be made is undoubtedly true, but I still do not believe the numbers generated would be sufficiently accurate for rigorous scientific applications. The counter argument is by using numbers that have been published in these champion lists, numbers are being used that have been vetted to some degree and represent a fair sampling of measurements taken with reasonable care by responsible individuals using those techniques.  

Ed Frank

Baseline Measurement Errors


I would like to highlight some of the problems with the traditional baseline methods.  I see four specific examples I want to discuss, there may be others: 1) The measurement may not be taken from a great enough distance to see the actual top of the tree, 2) The top can be seen but from the ground it determining which sprig forms the top is difficult using conventional baseline/clinometer methods. With a laser rangefinder the distance to the sprigs can be determined in real time where the most distant of several branches at similar angles represents the highest sprig. 3) The top measured using baseline methods may unknowingly be a branch extending outward toward the viewer rather than being the true top. This will result in the height being significantly over-estimated. By using a laser rangefinder these frontward extending branches can be distinguished easily. 4) The top of the tree may offset and not located exactly over the base of the tree. 

In a sampling of 1800 trees measured using the laser techniques found the tops of trees in the set to be offset an average distance of 13 feet from the top representing an average offset along the line of sight of 8.3 feet. In a 150 foot tall tree measured from a distance of 100 feet this average offset would lead to an average height error of 12.5 feet based on this average offset alone.  The actual top may be behind or in front of the base of the trunk along the line it is being measure.  If the top is located behind the trunk (farther from the observer) then the resulting height calculation would be low. If the top is offset toward the observer, then the resulting height calculation will be erroneously high. 

To elaborate half of the errors from the top of the tree being offset from the base would be greater than the average offset errors (and half the errors would be less than the average offset errors).   I think that the tops measured are more likely to be on the facing side of the tree than on the opposite side of the tree, but for calculation purposes we used to calculate actual offset, this front to back asymmetry is not important. [It could be calculated from the dataset]. Therefore the likelihood of a tree being measured resulting in a value that is too high, even if the actual top is found would be greater than the chance of it being underestimated. If the measurer is not hitting the top, then the result would be high in virtually every case. The laser lets you identify the top more clearly than other methods because it generates a distance number as the tree is being scanned.  The chance of not picking the correct top is much much greater when just guessing using baseline/clinometer methods than they are when using a laser. Most of the larger errors are the result of misidentifying the top, lesser errors are a direct result of the top not being directly over the base, even if it is identified correctly.

I have been encouraging Bob to use some trees that have been climbed and physically measured in his height measurement experimental designs.  I also have been lobbying Will and Bob to prepare a list of trees which have been climbed and measured by drop tape for which we also have laser/clinometer height measurements.

The point is that many people need to have the reassurance that all of the triangulation methods are actually somewhere close to right, and are meaningful. A taped measurement, even if older addresses that concern and adds weight to the entire argument. If you demonstrate that a taped measurement is close, or was close in height to the instrument and trigonometric calculations, then people will believe the instruments and trigonometric numbers are meaningful. 

Many people are so involved in using electronic, mechanical, and mathematical measurements and modeling, there is a degree of disjunction from members of the general public.  Most people do not regularly use nor fully understand math beyond addition and subtraction, and distrust science even more. How many advertisements do you see where people almost seem proud of their inability to use a computer? Trees that have been climbed and measured need to be included in any comparison of tree height measurements, no matter what the intended audience. 

Edward Frank

RE: Baseline Measurement Errors   John Eichholz
  Nov 06, 2005 04:36 PST 

Don't forget to mention that the methods we use are almost universally used by those who measure for a living. Surveying instruments have long ago switched to laser technology, and surveyors and engineers have long used trigonometry responsibly. It has been a long time since you have heard of a bridge that didn't meet in the middle. I think the Chunnel
met within millimeters:

Fear and ignorance has a long history. So does scientific progress.  Hey, my measurement of the Massasoit tree was right-on using a stick held out at arms length. -- You can get lucky, and the principle used is sort of correct. Its just that our methods are much more accurate and consistent, and luckily for progress, just as quick, as the old baseline method.



Species General Location Baseline/ Clinometer ENTS Laser/ Clinometer Error (ft) Error (%) Location Champion List Measurer Measurement Date Tree Name Post Date Post Author Notes
Water Hickory Southeast 148 128 20 16% Congaree NP, SC National Blozan   31-Oct-03 Blozan #001
Pignut Hickory Southeast 190 123 67 54% NC AF Blozan   31-Oct-03 Blozan #002
Red Oak Southeast 175 136 39 29% NC AF Blozan   31-Oct-03 Blozan #003
Tuliptree Mid-Atlantic 145 111 34 31% VA AF Blozan   31-Oct-03 Blozan #004
Red Maple Midwest 179 120 59 49% MI AF Blozan   31-Oct-03 Blozan #005
Rosebay Rhodo Southeast 42 29 13 45% SC AF Blozan   31-Oct-03 Blozan #006
Loblolly Pine Southeast 162 134 28 48% SC AF Blozan   31-Oct-03 Blozan #007
Sycamore New England 136 114 22 19% Pine Plains, NY Leverett   23-Jan-05 Leverett #008
Red Oak Mid-Atlantic 165 121 46 38% Cook Forest, PA Leverett   23-Jan-05 Leverett #009
White Pine New England  175  150.5  24.5  16% Pack Forest, Adinrondacks, near Warrensburg, NY SUNY Measurement Leverett Grandmother Pine 9-Sep-05 Leverett #010
Red Oak Mid-Atlantic 160 120.4 39.6 33% Leverett   23-Jan-05 Leverett #011
Bur Oak  Midwest 142   116.7 25.3 22%  Big Oak Tree SP, MO MO State Champion Bragg 29-Jul-05   3-Aug-05 Bragg #012
Pumpkin Ash Midwest 150 102.8 47.2 46% Big Oak Tree SP, MO National Bragg 29-Jul-05   3-Aug-05 Bragg #013
Persimmon Midwest 133 118.2 14.8 12.5% Big Oak Tree SP, MO MO State Champion Bragg 29-Jul-05   3-Aug-05 Bragg #014
Poplar Mid-Atlantic 128 111 17 15% Bedford, Virginia Leverett & Blozan 1997 Bedford Poplar 12-Sep-05 Blozan #015
Red Maple 126 110 16 14.5% Leverett L. F. Baum Maple 23-Jan-05 Leverett #016
Loblolly Pine Southeast 168 136 32 23.5% Congaree NP, SC Leverett   23-Jan-05 Leverett #017
Bitternut Hickory Southeast 153 146 13 9% GSMNP National* Blozan   31-Oct-03 Blozan #018
Bur Oak Southeast 140 118.6 21.4 18% NC NC Champion 2005   11-Sep-05 Blozan #019
Katsura Southeast 101 82 19 23% NC NC Champion 2005   11-Sep-05 Blozan #020
White Oak Southeast 153 116 37 32% NC Older NC Champ list   11-Sep-05 Blozan #021
Ginko Biloba Mid-Atlantic 148 98 50 51% Germantown, Philadelphia
  County, Pa
PA State Champion Scott Wade 1-Oct-04   12-Sep-05 Wade #022
Yellow Buckeye Southeast 154 128.8 Sosbee Cove, Union County, Georgia Georgia Champion Tree List, 1996 edition Jess Riddle 2-Sep-05   12-Sep-05 Riddle #23
White Pine Southeast 192 168 north Georgia n/a Jess Riddle   Luthringer #24
Swamp White Oak Northeast 120 89.6 30.4 34% Pennsylvania Pa State Champion 1993 Dale Luthringer 2004   06-Jan-06 Wade #25
Red Oak Northeast 155 110.3 44.7 40.5% Willistown twp, Chester County, PA  Pa Champion Nomination Scott Wade 2005   06-Jan-06 Wade #26
Southern Red Cedar Southeast 52 41.7 10.3 24.7 St. Simons Island, GA Informational Plaque- Ga State Champion, 2005 Jess Riddle 2006   08-Jan-06 Riddle #27





#002:  Will Fell reports there was no 190 foot pignut listed in NC by AF for last 10 years  Bob Leverett reported (2005-09-13):  "The 190-foot national champion pignut was located in Robbinsville, NC and was definitely listed in a past edition of American Forests. National Register of Big Trees.  I think it was in the late 1980s. I have the edition and will look it up. Michael Davie and Bob Van Pelt measured the tree, I think at different times."   Bob Leverett also reported that he believes that the tree fell.




#006:  Will Fell reports AF listing at 37 feet




#010:  Bob Leverett wrote (2005-09-05):  "The Grandmother Pine that I list is in Pack Forest. I met with two of the folks who measured the tree at 175 feet and I discussed their technique with them. I alerted my friend Professor Don Leopold at SUNY of the error. I didn't make it a big deal, but suggested that the forestry school might not want to continue publishing such a prominent error in their brochure. They were claiming it as the tallest pine in New York State. ...The measurers used a clinometer and a baseline."


#012:  Current state champ online is 84 feet in a different county, it is fatter and has a bigger spread.  Tree info from Big Oak Tree State Park sign, Sept 12,2005

#013:  Confirmed online listing Sept 12, 2005 State Champion List

#014:  Online state listing at 132 feet, park sign 131feet, Sept 12, 2005

#015:  Bedford Poplar

#016:  L. F. Baum Red Maple

#017:  Congaree Loblolly, Will Fell reports Jess Riddle measured it at 167, and that 126 is incorrect - not same tree

#018:  Mis-identified as a red hickory

#019:  NC 2005 champion listing confirmed, Sept 12, 2005

#020:  NC 2005 champion listing confirmed, Sept 12, 2005

#021  No listing for species found Sept 12, 2005

#022:  Big Trees of Pa 1993 booklet from Penna Forestry Association

#23:  Jess Riddle wrote (2005-09-12):  "Yellow Buckeye Originally listed as 154' tall in a November 1996 edition of the Georgia champion tree list My dad and I measured the tree on 7/2/05. Four measurements ranged for 127.2' to 129.4'. I think a 128.8' measurement is likely the most accurate one. The tree grows in Sosbee Cove, locally well known for botanical reasons, in Union County, Georgia. The tree remains healthy and the state champion. Will Fell has updated the measurements in the Georgia state list."

#24:  Will Fell wrote (2005-09-19):  "It is one of the state co-champion white pines (the other was nominated by Jess only a mile or two away) that was nominated by an FFA student and subsequently measured by a USFS person as being 192 feet. I will add though that I checked the tree with one of our local GFC foresters and came up with a figure within a few feet of Jess's using a clinometer and calculator. Because of the extremely steep slope we had to calculate the actual horizontal distance from the top because it was significantly less that the ground distance taped up the slope. If we had a clear view and had shot from a location at the same general elevation by taping out on the contour, we wouldn't have needed to apply the trig formulas. As I recall we came up with about 165 feet and Jess later came up with 168. I then deferred to his measurement, one because I had more faith in his numbers, but I have to admit I was glad to have the few extra feet he added."  Jess Riddle wrote (2005-11-05):  "The white pine from north Georgia, # 24, was originally listed in a Georgia Champion Trees list, but I'm not sure what year. I believe the 168' measurement is from January 2001, but it might by January 2000'"

#25:   Scott Wade wrote:  Dale Luthringer had measured a Q. bicolor in 2004 that was a state champ at 120' tall.  Dale measured it at 89.6'.

#26:  Scott Wade wrote:  In the [PA State Champions] nominations I just inherited, there is a Red oak that was reported as 217" cbh 155' tall and 57' spread. It was close by, so I went out and took a look myself. The original measurements were done with a clinometer only by someone that has taught others to measure n the past using such a device. My measurements came out as follows:  217" CBH 110.3' tall with an average spread of 84' total of 348 points. Myth Busters wins again! the tree is in Willistown twp, Chester county on the Crumdale farm property. 

#27:  Jess Riddle wrote:  St. Simons Island on the Georgia coast...the state champion southern red cedar (Juniperus silicicola).  The tree's massive spreading limbs produce a memorable image and support a broad crown with an undulating upper surface... That structure produces many tops of similar height, and several of those tops are laterally greatly displaced from the base, a leading cause of height errors.  Contrastingly, the site offers excellent measuring conditions; the ground is flat, and the open grounds offer completely unobscured views of the crown from multiple directions.
While the tree definitely has a single stem, the branches emerge low enough to swell the trunk at 4.5', another source of potential error.  A plaque beside the tree states a local garden club (?) now looks after the tree's health, and declares the southern red cedar the second largest in the state and second largest in the country.  The national champion in Florida has only slightly more points, but the tree remains on the Georgia list as the state champion.  The plaque also indicates the tree has been measured by foresters three times:  first in 1976, once in the 1980's, and most recently in 2004.  The dimensions listed on the plaque, presumably from the most recent measurement, are 16.6' circumference, height 52', and spread 80'.  Measuring at the 3' high waist, I got a circumference of 16'5", pretty close.  However, the highest live top I could find was 41.1', and a recently killed top was 41.7'.  Another top a foot higher might be hiding within the crown, but the height certainly does not approach 52'.  Even under these good conditions, purported experts failed to measure the tree's height accurately.