Upper stem volumes from stem analysis data: an overlapping bolts method

Abstract

Studies to develop equations for upper stem taper, volume, and weight require observed values of upper stem volume. Tree volumes up to various upper stem diameters calculated using Smalian's formula throughout the stem length on 4- to 8-ft (1 ft = 0.30 m) bolts may overestimate true volumes by 1 to 4%. Calculating the butt bolt's volume with Newton's formula improves the estimates considerably. A new approach that uses Newton's formula on successive overlapping pairs of bolts produces even more improvement and still gives volume estimates for each bolt. The overlapping bolts method on 6-ft bolts is equally as precise as the conventional non-overlapping method on 4-ft bolts and would result in a 33.3% savings in sampling effort.