Chemical properties associated with bacterial wetwood in red oaks

Bacterial wetwood is a major cause of value loss in the red oak lumber indu stry in the United States. Red oak trees in Mississippi, South Carolina, an d Florida were sampled and evaluated for certain chemical properties possib ly associated with the wetwood condition. Specific variables investigated w ere pH and concentrations of methane, cations (Na+, C++, K+, and Mg++), non structural carbohydrates, and organic acids (acetate, propionate, and butyr ate). The degree of bacterial wetwood infection and development was greater in re d oaks from Mississippi than from South Carolina as evidenced by increased concentrations of methane, total Na+, total K+, total Ca++, and by decrease d concentrations of total sugar and reducing sugar. Of all the variables te sted, 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 li ving trees or in green red oak lumber Of the remaining variables tested, gr eater concentrations of acetic acid, total K+, and lesser concentrations of nonstructural carbohydrates characterized wetwood-affected trees, but thei r potential as wetwood indicators depends on wetwood severity, not its mere presence.