Although significant volumes of Alberta's trembling aspen resource are being used for pulp and for oriented strand board production, the species can be accurately referred to as "under-utilized" with respect to the production of solid wood products. It is well documented that the aspen's external indicators of quality correlate poorly with internal characteristics, making it particularly difficult to identify suitable sawlogs. This means that the greatest challenge around cutting aspen into solid wood products continues to be the identification of logs that are of suitable quality.
This report details the development of an experimental log grade rule for use when evaluating aspen logs. The rule was developed to more accurately segregate those aspen logs that can be profitably cut to high-valued solid wood products from those more suitable for conversion to oriented strand board or pulp. In the first phase of the study, three samples each consisting of thirty logs that met the revised criteria were sawn, and lumber grade yields were calculated. Although the results were encouraging, it was recognized that larger samples needed to be evaluated. To this end, in the second phase, additional, larger samples were sawn, and grade yields again determined. Test results from the second samples largely replicate the first samples and show that logs that meet the revised criteria will more consistently yield high grades of lumber.
The question of available volumes of the experimental log grade is also an important one. This report describes evaluations of aspen logs in inventory at three large manufacturing facilities in Alberta. It is inferred that between 1.5% and 3.5% of the log volume in sampled inventories meet the criteria for new log grade. Recommendations for follow up work include: detailed case studies that consider all of the economics of building and operating an aspen grade mill; a more comprehensive analysis of harvested volumes of aspen in order to more accurately estimate the available volumes of sawlogs meeting the standards for the new log grade rule; an analysis of the costs and benefits of using x-ray scanning technology to sort out aspen sawlogs from those more suitable for pulp or oriented strand board production; and an analyis of remanufacturing opportunities based on estimated yields of cuttings from the experimental log grade.
AFRI - AFRI-711G-05 pertaining to Populus - Utilization; Value added - Alberta; Grading - Logs