Establishing Correspondence in Wood: The Challenge and Some Solutions?

Establishing correspondence between the upper portion of a white birch sapling, a suspected weapon, and a potential source from a stand of trees was posed to one of us ( GMC ). A bending force shattered the sapling, precluding physical matching. Three white birch saplings were taken from the same stand of trees in a similar manner. Correspondence was achieved by measuring the width of the annual rings along four radii from a disk cut above and below the break. The regression coefficient of the data from the two disks from the same sapling was r 2   =   0.95. Regressing the upper disk against the lower disk of two other saplings resulted in r 2 values of 0.26 and 0.17, respectively. The various characteristics that are confined to a wood stem as part of its normal process of growth can be used to eliminate candidate saplings and establish correspondence between two pieces of wood.