Examine both ends of each log for rot. Pick at any areas that seem crumbly, using the pocket knife. Easy removal indicates decay. A log with rot at both ends is not lumber mill quality. If the log has rot only at one end, you may be able to remove that area, so mark a cut with the lumber crayon. Also look for "catfaces," or openings surrounded by slightly raised lips of wood along the log's length. Check for cankers, or dead spots, which are usually sunken and may still have bark. Mark these for removal.
Check the end of each log for large swelling, crookedness, large splits and evidence of shattered wood. Mark the log to cut off these defects.
Examine both ends for "heart checks," splits that run across or near the center at right angles to the annual growth rings. Look for frost cracks going from the outside of the log to the heart. Determine twist in these defects by putting a small stick in the bark, parallel to the check at one end, then viewing the check at the other end. Mark the log for removal from the quality logs if these spiral and run the length of the log. Mark the log for cutting a short distance in from these defects if they exist only on one end.
Look for external cracks and splits along the length of the log. Test the depth of cracks with the pocket knife. Mark the log for removal from the quality logs if it has cracks or splits that are deep and spiral the length of the log.
Examine the log's straightness and mark it to cut out any crooked parts.
Check for "pig ears," or branches that aren't cut flush with the log. Mark to have them removed.