Identification of Wood Fragments in Trace Evidence

From time to time, wood plays an important role in solving criminal cases. Wood samples vary in size and can range from trees and logs to pieces as small as individual wood fibers. Botanists can easily identify trees. especially when the leaves, flowers. or fruits are present. Using standard techniques. wood technologists. foresters, and wood anatomists can generally identify logs, lumber, wood products. and pieces of wood bigger than a matchbox. As the size of the piece decreases, however, accurate determinations are more difficult. Very small fragments require special handling and identifica­ tion techniques. This paper describes the techniques used at the USDA Forest Service, Forest Products Laboratory (FPL) to handle and identify different sizes of wood fragments. Some examples of actual cases are also pre­ sented.