To saw or not to saw – answers to the question of minimum feasible hardwood log diameters for conversion to lumber

by

Jan Wiedenbeck, Matthew Scholl, Paul Blankenhorn

USDA-FS, NRS-01, Princeton, WV

Abstract – A company that owns, buys, or processes hardwood logs should know the profit potential of different qualities and sizes of logs of different species. This profit potential changes over time depending on stumpage costs, the value of potential end products, and the demand for logs from different wood industry sectors within the region. Many hardwood logs less than 12-in diameter that were being sawn into lumber before the recession began to be chipped for pellets or converted into industrial products when demand for housing and related products fell in 2008. To understand the profit potential of smaller hardwood logs it is necessary to know the expected lumber yield, lumber grade, and cost of processing logs that may be considered marginal-sized sawlogs. The grade yields and defect occurrence associated with logs 11 inches or smaller in diameter were evaluated for black cherry (Prunus serotina Ehrh.), red oak (Quercus rubra L.), and sugar maple (Acer saccharum Marsh.). Alternative lumber drying protocols were used to try to reduce drying related defects which are a concern for these smaller logs. Before and after drying each board was examined to identify all defects that can be associated with drying; for example, checks, crook, shake; and assigned a lumber grade. Overall, for all three drying protocols, lumber grade yield increased with increasing log diameter and log grade. Losses in lumber grade associated with drying were evident for all three drying protocols with no evidence that the smallest diameter logs in the sample (7- and 8-inch) suffered greater grade losses than the larger logs in the sample. This study provides important information and insights into processing smaller diameter hardwood logs that in certain situations may be profitable sawn.