TRIALS OF 3 FUMIGANTS TO PREVENT ENZYME STAIN IN LUMBER CUT FROM WATER-STORED HARDWOOD LOGS

Sapwood discolorations such as sticker stain in ash or gray stain in o ak cause substantial losses to lumber producers in many areas of the U nited States. Commercial grade logs of sugar hackberry, white ash, and southern red oak were fumigated at atmospheric pressure under plastic tarps with methyl bromide, sulfuryl fluoride. or methylisothiocyanate in an attempt to kill living parenchyma cells and thereby prevent enz yme-mediated discolorations of lumber cut from treated logs after 4 mo nths of outdoor water sprinkler storage. The methyl bromide treatment prevented all discolorations in ail species, which correlated with dea th of parenchyma. The other fumigants were less effective in preventio n of stain (depending on wood species) or in killing parenchyma under the conditions of the test.