A primary focus of the Native Tree Society is the promotion of accurate tree measurement protocols and development of new and better measurement techniques.
NTS SP #1a Tree Measuring Guideline of the Eastern Native Tree Society -Revised by Will Blozan
Will Blozan writes: The most significant difference between ENTS measured trees and those measured via conventional forestry methods is a much higher standard of accuracy. In fact, the "ENTS method" of laser-based tree height measurements is so accurate that it is being employed in height growth monitoring projects by several universities and premier forest ecologists. Perhaps the most important value of the ENTS method is that it is repeatable, a basic premise of any scientific project. Users of the method, with a few minutes of training, can produce measured results within 1% or less of a seasoned ENTS researcher. Seasoned ENTS researchers can measure a tree from the ground to within inches of a direct tape drop. This process takes but a few minutes for most trees.
NTS SP #9 The Really, Really Basics of Laser Rangefinder/Clinometer Tree Height Measurements by Edward Frank
Archive of Older Measurement Discussions
Measurement and Dendromorphometry Forum on the NTS BBS