Finn caliper

Revision as of 18:56, 17 February 2011

Figure 1 The Finn caliper: fixed on a pole the tree diameter can be read up to a height of 7m (Keller 2005^[1]).

The Finn caliper (also called Finnish parabolic caliper) is used to measure the stem diameters at (or up to) 7 m (d7m). Figure 1 gives an illustration. By its name, it is originally from Finland and is being used in Northern European countries as well as in Germany and Switzerland. With pole and caliper, the height of 7 m has been found to be the maximum still manageable one; that is, it had been defined for practical reasons only.

The Finn caliper is relatively difficult to carry in the forest because the device consists of several calipers and various poles that are put together for the measurement.