Predicting resin pockets in radiata pine logs from blemishes on log ends

More than 120 radiata pine (Pinus radiata D. Don) sawlogs, from two sites, were assessed for resin pockets and blemishes (resin streaks, bark pockets, colored marks, and other grain deviations) on the log ends. At both sites, the assessment of blemishes on the log ends improved the prediction of resin pockets on the lumber after sawing (r(2) = 0.29 and 0.49), beyond the prediction achieved by assessing resin pockets on the log ends alone (r(2) = 0 and 0.24). Noting only the presence or absence of blemishes on the log ends enabled explanation of half the variation between logs in loss of clear cuttings due to docking out resin pockets from the lumber (r(2) = 0.50, P < 0.001). Since the log ends were assessed after ordinary chainsaw cuts were made, we believe that blemishes could be recognized by log graders, and that it should be possible to develop selection procedures for sawlogs that minimize the value losses associated with resin pockets.