Posted: Mon Feb 06, 2017 12:35 pm
by dbhguru
Ents,

We continue working on methods for computing a functional circumference to compensate for abnormal or atypical forms of tree trunks. Our primary purpose is to support the champion tree programs, state and national.

One approach that Don Bertolette and I have been pursuing for literally months is to investigate methods for computing circumference at 4.5 feet based on the form of the trunk above that level projected down to 4.5 feet. This approach can only logically be applied to compliant trunks that show a predictable taper. The attachment offers computational algorithms. It is by no means a panacea - just another tool in the toolkit.

Both Don and Jared Lockwood are testing the methodology provided in the Excel workbook. They will project the circumference at 4.5 feet using trees that are "well behaved." If the Excel models hold up, then applying at least one of them to trees with distorted shapes at 4.5 feet would seem to be justified. After cataract surgery in both eyes this month, I'll join the testing. Anyone out there in NTS land who would like to join in either with criticisms or helping us test these models, we would be most appreciative. For those of you who have endured my spreadsheet solutions, you'll note that there is usually an introduction followed by a spreadsheet calculator. I usually include the development of any formulas somewhere in the process. In this case, I've eliminated the mathematical derivations and just presented the final formulas. If anyone wants the derivations, let me know.

As some final observations, in the past NTS was the vehicle for developing and applying better tree measurement methods for circumference, height, crown spread, and to a lesser degree, trunk volume. Through our efforts, we have worked our way into a position of importance with American Forests (Measuring Guidelines Working Group and Cadre) and now with the VA Tech Dendrology Dept. Most of our more technical efforts will be expressed through the latter two organizations, but the crucible from which idea spring will likely continue to be NTS.

Bob