The number of ticks covering tree stem at the place of diameter measurement together with information on used zoom factor are required. It is possible to calculate the diameter in millimeters and the horizontal distance to the stem center upon receiving of data on:

  • inclination to stem base
  • inclination to the first diameter measurement
  • horizontal distance to the stem surface
  • ticks reading


       

With such information it is possible to calculate other diameters simply based on the inclination and reading of spotting scope scale bar. Measurement of the first diameter is necessary to get information on the horizontal distance to the stem center. In most cases the first diameter can be measured at the required place and the whole measurement procedure is finished.

Alternative A: Measurement without measuring pole reflector

Inclination to the stem base is measured straight to the center of the stem at ground level ("through the stem"). This alternative is suitable in case of good visibility of the target tree; no understorey. Your device has to support nonreflective targets.



Alternative B: Measurement using measuring pole reflector

The inclination to the stem base is measured from the reflector of the main pole. The pole needs to be placed at the ground level of the tree stem base. The distance and direction of the pole position in relation to the center of the stem does not have any influence on the measurement procedure.



Alternative C: Measuring diameters using pole with reflector

Unlike in “B” the measurement of the inclination to diameter height is obtained by using the reflector on the main pole. You always have to use the reflector where there is dense vegetation and you need to have the “Foliage filter” on