Sight versus Sound: Do Visual Assessments of Dead Standing Trees Reflect Acoustic Nondestructive Evaluations of Wood Quality?

The forest industry typically uses visual appearance to evaluate the wood quality when salvaging dead standing trees. We investigated whether the visual appearance of white spruce (Picea glauca (Moench) Voss) defoliated by the spruce budworm (Choristoneura fumiferana (Clem.)) accurately reflects wood quality measured using nondestructive techniques. Longitudinal and transverse acoustic velocities were measured on white spruce, representing three condition categories assessed visually, ranging from live trees to dead standing trees with signs of decay. Generalized linear models were used to determine whether there were significant differences in longitudinal and transverse acoustic velocities among the visual categories. Longitudinal velocities significantly differed between the live and poorest visual categories. Transverse velocities did not differ by visual category. We found that tree appearance provides coarse but useful insight into intrinsic wood quality. We recommend that forest managers use acoustic, non-destructive technologies on marginal trees to measure the wood quality of salvaged trees to ensure the wood is utilized for the highest and best use thereby optimizing possible values.