Quality and Size of Melina Logs and Sawmilling Yield

Abstract

294 logs of Gmelina arborea were analyzed, coming from an 8 year-old plantation, located in Río Grande de Paquera, Puntarenas, Costa Rica. It was considered the effect of the quality and the thickness of the logs on the yield of the lumbering process using a portable sawmill. The logs were classified in quality A, B and C. A total amount of 81 logs were used for quality A, 182 for the quality B and 31for the quality C. Based on the thickness of the logs 4 classes were settled down with a width of 2 inches (5,1 cm) using the mensurational system known as the “rope system”. The average diameter of the sample was of 7,5 inches (19,1 cm). The minimum value was of 3,5 inches (8,9 cm) and the maximum value of 11,5 inches (29,2 cm). The longitude of the logs varied between 1,25 m and 3,49 m. The yield of lumbering averaged 52,75 per cent generating a waste of 47,25 per cent. The largest lumbering yields for diameter classes were represented by the class of 8,5 inches (21,6 cm) achieving 70,04 per cent and the smallest yields for the class of 6,5 inches (16,5 cm) with 36,62 per cent. As for the quality of the logs, those that presented the largest yield were located in the quality A and the smallest yield was obtained for the quality C logs.