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
One of the major constraints to the growth and development of a value-added sector for trembling aspen in the solid wood industry concerns the inherent variability in quality of the resource. Much of the resource is simply not suitable for the extraction of lumber grades required to service markets for higher valued wood products, and those logs that are suitable for grade extraction are often difficult to identify. Recent market research details an interest in higher valued grades of aspen, particularly in Asia. On the basis of that market research it is worth investigating the predictive value of an alternative system of identifying aspen logs well suited for the production of high-grade lumber.
This report details the conception and application of an experimental log grade rule for use when evaluating samples of aspen logs. The rule is intended specifically to separate high valued aspen sawlogs from those more suitable for conversion to oriented strand board or pulp. The log grading system presently used to evaluate most hardwood logs that are graded, one developed by the United States Forest Service, has been shown to do a poor job in estimating the value of aspen logs. The new log grade rule was based on the existing system, which was modified slightly to reflect some inherent characteristics of aspen. Three samples each consisting of thirty logs that met the revised criteria were evaluated. Test results reported here show that logs that meet the revised criteria will more consistently meet higher grades of lumber; however, more work must be done to confirm the predictive value of the new rule. In addition the issue of available volumes of logs meeting the revised criteria must be addressed.
AFRI - AFRI-700VA-03 pertaining to Populus - Utilization; Value added - Alberta; Grading - Logs