Robert, Steve, et al.,
The eastern cottonwood is probably one of the most mis-measured trees in terms of height. The crowns of big cottonwoods are often very wide and it isn't obvious where the top is. Using the dumbed-down approach of applying the tangent method, we've see extremely large height errors coming from folks we would otherwise consider to be competent professionals. Poor measurements are published and republished in sources that are supposed to be authoritative and we end up with the situation we now have. An amateur comes along and mis-measures a tree without suspecting it, and if challenged, can turn to the assumed authoritative sources to justify the offending measurement. Outsiders have no way of knowing or reason to suspect that large errors exist in authoritative appearing sources. Alas, it is the measuring world in which we live.
One reason that Will Blozan, Dale Luthringer, and I have pushed tree measuring workshops at Cook Forest and MTSF in recent years is to try to bring forestry professionals who certify tree measurements for champion tree lists into the inner circle of competent measurers. But it has proven a tough sell for a variety of reasons including misplaced pride, lack of interest, lack of time, and inadequate math skills on the part of potential attendees.
Robert T. Leverett
Co-founder and Executive Director
Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest