LOG FUMIGATION PREVENTS STICKER STAIN AND ENZYME-MEDIATED SAPWOOD DISCOLORATIONS IN MAPLE AND HICKORY LUMBER

Methyl bromide fumigation of sugar maple and hickory logs was done to note its influence on the development of oxidative type non-microbial sapwood stain in lumber processed at a northern Indiana sawmill. Lumbe r from fumigated and matched control logs was kiln-dried, planed, and graded two separate times according to normal industry practices. The first grading ignored the presence of non-microbial stain and sticker shadow; regrading was then done with such discolorations considered as defect. Oxidative stain in control lumber was substantial (29% of hic kory and 41% of maple board foot (BF) volume), but it was completely p revented in fumigated hickory and reduced to less than 10 percent in t reated maple. There was only a low level of stain in maple and that st ain was from the single log that showed incomplete kill of the parench yma due to tarp contact during fumigation. It was evident that fumigat ion of maple results in a greater tendency for the logs to develop fun gal stain during outdoor storage.