Measuring Diameter
DBH is generally measured at 4.5 feet off the ground. For most trees taking the diameter at 4.5 feet above ground is appropriate, but occasionally you will encounter situations that require measuring higher or lower than 4.5 feet. In order to have a useful inventory it is essential to be able to come back in the future to determine how your trees have grown and changed, so it is important to record the height at which you measure the diameter to enable repeatability in the future. Most older trees can comfortably be measured at this height, so it is very helpful to know where 4.5 feet off the ground lines up with you body so you do not need to continually use a measuring device at every tree. If you are looking to do a basic inventory you may not feel a need to get an exact measure of every tree, and for the sake of simplicity using size classes can be just as effective. The standard size class for i-tree is 0-3, 3-6, 6-12, 12-18, 18-24, 24-30, 30-36, 36-42, and everything larger than 42 gets put into 42+.
To learn the appropriate technique for measuring trees Click here.
To learn the appropriate technique for measuring trees Click here.