Chemical Brown Staining of Douglas-Fir Sapwood

Prevalence of a chemical brown stain in sapwood of Douglas fir during the first half of 1981 caused acute financial losses to Oregon producers of valuable clear grades of export lumber. Surface-stained lumber from two mills was used to evaluate potential stain-preventive treatments and the possible role of microorganisms in staining. The treatments investigated included storage under water sprays, dipping in solutions of sodium bisulfite and azide, reduced 02 supply, and steaming. The effect of dipping in a sodium pentachlorophenate solution also was evaluated. Bacteria and fungi were found in both stained and unstained wood, but their association with brown staining was not shown. The dip treatments had little or no practical effect. Steaming sapwood to 212?F was by far the most effective stain-preventive treatment. It also provided the in-depth protection needed if undried lumber is to be resawn.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member