VOLUMETRIC YIELD AND DIMENSIONAL QUALITY OF LUMBER IN SAWMILLS OF EL SALTO, DURANGO

Abstract

A volumetric yield and dimensional quality evaluation of lumber was carried out in five sawmills of El Salto, Durango, Mexico. For this ending, a monitoring of the products from 412 pine logs with a volume of 293.73 m3 r without bark was done; 7,085 pieces of different dimensions and grades with a corresponding sawn volume of 169.01 m3 were obtained, with a lumber yield of 57.5%, that is equivalent to 244 board feet by each cubic meter of roundwood sawn timber. The largest volumetric yield of lumber by quality class was observed in pieces of number 5 class with 86.49 board feet, whereas, by nominal thickness, the main volumetric yield lumber was for the 7/8 boards with 95 bf.. In regard to nominal width, the greatest yield was found in 203.20 mm (8”), with 78 board feet and, in terms of length, the major lumber recovery was obtained in 16’ (4.87 m) with 115 board feet. Considering the quality of the sawmill process, the mean thickness to which lumber is sawn was not enough to support drying and plane boards with final dimension of 22.23 mm (7/8”), while for the of 31.75 mm (5/4”) thickness, the sawn boards were oversized in El Brillante ejido; on the other hand, 38.10 mm (6/4”) lumber from La Victoria ejido, the mean thickness was compatible with the estimated target size. The findings of this study suggest the need to establish a control system, in order to ensure the dimensional quality in the lumber sawmilling process.