Manipulating grading strategy for the efficient harvesting of industrial poplar plantations

New short rotation poplar plantations yield a mix of biomass and logs, whereby the latter are used for board production and represent the most valuable component. Therefore, there is an interest in maximizing log yield, which must be balanced against the incremental time consumption incurred for manufacturing any additional logs. This study explored the optimization potential of manipulating log specifications and grading instructions in order to decrease time consumption or increase log yield. A controlled experiment was set up to determine the merits of 1) renouncing the manufacturing of a second small log to expedite processing or 2) decreasing small end diameter to increase the proportion of viable logs in any given stem. The experiment indicated that strategy one did not pay, since the productivity increase was minimal and non-significant, while the log yield losses were meaningful and significant. In contrast, strategy two was efficient in increasing log yield, without any negative effects on harvesting productivity.