Anaerobic bacterial infection increases the proclivity of red oak lumber to develop surface, internal and end checks, and develop or aggravate ring failure during drying. It also extends the drying time. Bacterial infection is hard to identify before drying without the use of costly, time- consuming tests. Thus, there is a need for an inexpensive, rapid and accurate method for the identification that can be used at a mill.

This research project investigated the possibility to use stress wave timing for the identification of bacterial infection, by studying the relationship of the level of bacterial infection and impact-induced stress wave travel time across the grain of green 4/4 red oak lumber from Southcentral Virginia. Bacterial infection increased stress wave travel time, but a considerable overiap existed between infected and uninfected boards.

Tests on tensile strength perpendicular to grain, which is critical for lumber to check during drying showed a decrease in strength due to the bacterial infection. A parallel kiln- drying experiment, following a standard drying schedule (T4D2), showed more drying defects in the infected lumber than in the uninfected lumber. Defects were also more frequent in lumber with a long stress wave travel time than in lumber with a short stress wave travel time.