Fastener in a harvester for a measurement caliper for measuring of the diameter of trees, which caliper (2) comprises a ruler (3) with a fixed and a movable shank (4,5) and a housing (6) arranged by the fixed shank, which housing (6) contains electronics for a measurement system belonging to the caliper as well as a display. The invention is characterized in that the fastener (1) comprises a first (7) and a second (8) U-shaped respective fastening means, arranged at a distance from each other, as well as a third (9) U-shaped fastening means in which the U is located perpendicularly to the U:s of the first (7) and second (8) fastening means, respectively, in that the third fastening means (9) is located outside a line through the first and second fastening means and beyond one of the first and second fastening means, in that the first (7) and second (8) fastening means have respective inner dimensions that correspond to the outer dimensions of the calipers ruler (3), and are arranged so that the calipers ruler (3) can abut against the respective bottom (15) of the first (7) and second (8) fastening means, in that the third fastening means (9) has an inner width that corresponds to the total width of the shanks (4,5), or their fastening arrangement, when these are translated into abutment against one another.
