Abstract: A method and apparatus for assessing standing tree stems for readiness for harvesting, or for determining cutting points for processing of felled tree stems, logs, or wood pieces, or for assessing stems, logs, or wood pieces for a particular end use, includes scanning with short-wave or microwave electromagnetic energy and processing the scan data to produce an image indicating the external shape or dimensions of the stem or log and hidden internal characteristics and their position, and assessing the image. Knots and/or whorls, which are not visible from the exterior and the depth of the clear wood sheath from the surface, may be determined.