Comparing Batch Log Studies to Individual Log Studies: Part 1 - Batch Studies

Batch log studies are frequently used by sawmills to provide insight into lumber grade yields and overrun for a given log grade. This information is then used to determine log pricing. These batches often contain logs with a wide range of diameters and clear faces. Little research has been done to determine the reliability of a batch log study for use in determining log break-even pricing. A series of 16 batch log studies were conducted at a hardwood sawmill to gain insight into the accuracy and reliability of the batch log study method. Batch compositions were found to be statistically different in four of five log grades. These statistically different batches led to statistical differences in lumber grade yields and overrun. The batch log study method does not provide accurate insights into lumber grade yields and overrun. As a result, these data are not reliable for mill management decisions such as the calculation of log prices. Several changes could be made to improve the batch log study method, but the individual log study method would be of much more use to mill managers.