Wet storage of hickory pulpwood in the southern United States and its impact on bark removal efficiency.
1996
Belli M.L.
Compared to other hardwood species, true hickory (Carya sp.) is extremely difficult to debark during much of the year. Ease of bark removal is a direct function of the shear strength of the cambium. This study investigated the effect of wet storage on facilitating bark removal of hickory using both an existing drum debarker and a flail delimber/debarker. A total of 700 tonnes of hickory logs were collected and placed in two piles, one under a sprinkler system and the other in dry storage. Cambial strength was monitored over time by taking increment cores and performing a mechanical shear test at the wood-to-bark interface. The logs were recovered and processed after 80 days in storage. The wet-stored logs showed 100 percent bark removal with an average shear strength of 930 kPa. The dry-stored logs showed less than 10 percept bark removal with an average cambial strength of about 3200 kPa. Chip samples were collected and bark content of the wood chips was determined through hand separation. Accepts bark content for unscreened material was 3.9 percent for dry-stored material and 2.5 percent for wet-stored material. A subsample of about 115 tonnes of the wet-stored material and a few tonnes of the dry were debarked using a flail debarker. Accepts bark content for unscreened wood chips was 0.5 percent for wet-stored material. The flail removed very little bark from the dry logs.
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