Discarded Small-Logs Recovery from Natural Forests: Improving the Value Chain

Abstract

This study investigates how small logs from native trees, which fail to meet standard sawing criteria, can be utilized to enhance their value by producing solid wood for direct use or remanufacture rather than being relegated to biomass or fuelwood. We analyzed a sample of 177 small, discarded logs from native species from second-growth forests of Nothofagus in the Ñuble Region, Chile. The logs were scored after a qualitative and quantitative assessment for small logs, as designed in this study, and processed using a flexible sawing pattern to optimize wood recovery based on random lengths, widths, and thicknesses. Log dimensions varied, with lengths from 31 to 156.2 cm, small end diameters from 11.5 to 25.6 cm, and volumes between 0.001 and 0.092 m3. Key defects in logs included knots (95%), curvature (79%), and checks (46%), among others. A key result is the obtained general yield value of 36%, a considerable value for small-diameter, low-quality logs. The highest sawing yields were achieved with Nothofagus dombeyi (Mirb.) Oerst (42%), Geviuna avellana Molina and Persea lingue Miers ex Bertero Nees (39%), and Nothofagus obliqua (Mirb.) Oerst (34%). The quality of the boards correlates positively with the quality of the logs, and the yields with the log size and quality. The yield achieved in boards coming from such low-quality logs shows a promising possibility of improvement for this kind of process. Further development of the grading process and automation of the sawmill process could be future research steps.