Abstract

In the photographic method, a photo is taken of the tree with an object of known reference height beside it. An inexpensive cell phone camera can be used. The tree height is calculated by using a ruler to measure the tree height and reference height on the photo. Previously, this method was thought to be accurate only if the distance to the camera was many times the tree height. However, if the cell phone is held vertically, at a right angle to level, this eliminates the optical foreshortening in viewing a tall tree. The photo method produces a very accurate estimate of tree height. By using this method in a test experiment, the photo method had an inaccuracy of less than 1%. The most common measurement methods used by professionals are the tangent and sine methods, which use clinometers and laser rangefinders. These methods require measuring the distance to the tree, the elevation of the instrument above the base of the tree, and the angle to the top of the tree. The photo method is easier and potentially more accurate than the tangent and sine methods. It can be used by forestry professionals and the general public.

Key words: Tree, height, measurement, eastern white pine.