A Simplified Method of Sampling Logging Residue

The line intersect technique for estimating the volume of logging residue was field tested in British Columbia from 1965 to 1967. Residual volumes could be satisfactorily estimated from two sets of sampling lines oriented at right angles. Angular orientation of the residue to the sampling lines could be represented by a constant factor on both tractor- and cable-logged areas.The only variable requiring measurement was the mean cross-sectional area of pieces intersected by a sampling line. When this was estimated by measuring the ends of each piece, the line-intersect method saved an average of 36 percent of the total sampling time required for volume estimation by conventional sample plots. A significant additional reduction in sampling time could be achieved by measuring the cross-sectional area of pieces at the plane of intersection with the sampling line. To avoid bias, this should be accompanied by a sub-sampling procedure involving measurement of end areas on 25 percent of the pieces. Using this sub-sampling procedure resulted in an average reduction of 55 percent of the plot-sampling time required.