CHEMICAL PROPERTIES ASSOCIATED WITH BACTERIAL WETWOOD IN RED OAKS Zicai

Bacterial wetwood is a major cause of value loss in the red oak lumber industry in the United States. Red oak trees in Mississippi, South Carolina, and Florida were sampled and evaluated for certain chemical properties possibly associated with the wetwood condition. Specific variables investigated were pH and concentmtions of methane, cations (Na+. Ca++, K+, and Mg++). nonstructural carbohydrates, and organic acids (acetate, propionate, and butyrate). The degree of bacterial wetwood infection and development was greater in red oaks from Mississippi than from South Carolina as evidenced by increased concentrations of methane, total Na+, total K+, total Ca++, and by decreased concentrations of total sugar and reducing sugar. Of all the variables tested, methane concentration was the best indicator of wetwood in living red oak trees at all three locations. pH was not an indicator of wetwood in living trees or in green red oak lumber. Of the remaining variables tested, greater conc@xations of acetic acid, total K+, and lesser concentrations of nonstructural carbohydrates characterized wetwood-affected trees, but their potential as wetwood indicators depends on wetwood severity, not its mere presence.