Abstract

To meet the ever-increasing demand for timber, it is necessary to maximize the utilization of trees. Forestry practices have traditionally harvested only large-diameter trees (DBH > 25 cm), overlooking the vast potential residing in small-diameter stems (DBH < 15 cm) and the top parts of large-diameter trees. This issue is also evident in Tanzania, causing the industry to face underutilization of small-diameter logs. This paper aims to determine processing efficiency by utilizing small-diameter parts of the stem through product diversification. Specifically, the study sought to compare the recovery rate and productivity between conventional sawing (CS) and integrated sawing (IS). A study was conducted at the Forestry and Wood Industries Training Centre, a processing industry in the Southern Highlands of Tanzania. Two sets of logs were considered: one for CS to achieve lumber only, and the other set for IS to achieve all possible products. The recovery rate was measured as the volume of usable product divided by the log volume. Productivity was measured with time studies during log processing. The findings show that 65% was recovered with CS; of this, 41% was converted into large-size lumber, 24% into planks (sideboards), and the rest was considered waste. Under IS, 98% of the processed logs were recovered into usable diversified products: 50% large-size lumber, 26% small-size lumber, 18% briquettes, and 4% planks. CS had a processing productivity of 0.64 lumber m³/h, while IS had 0.73 lumber m³/h with the slide tech machine and 0.56 m³/h for IS small-size lumber with the double warbour machine. This study showcases the added value of also using small-diameter logs with IS, thereby supporting the efficient utilization of wood.

Key words: Conventional sawing, integrated sawing, productivity, small-diameter log.