CRUSHING STRENGTH AND MODULUS OF ELASTICITY OF UNMACHINED LODGEPOLE PINE STEM SECTIONS COMPARED TO MACHINED DOWELS OF THE SAME DIAMETER - KERFED AND KERF-FREE, ROUND AND HALF-ROUND.

Six-inch-long cylindrical or half-cylindrical stem sections from suppressed stands in two western Montana locations, tested when dry in compression, showed that specific gravity and two mechanical properties - maximum crushing strength parallel to the grain, and modulus of elasticity (MOE) - are positively correlated with average rings per inch. Unmachined (not doweled) 2-inch-diameter and larger rounds have about one-third higher MOE and one-tenth higher maximum crushing strength than dowels of the same diameter that have had 1/4 to 1/2 inch of radius machined from them in the doweling process. A sub-experiment indicated that MOE of cylindrical stem sections nondestructively measured in compression parallel to the grain did not differ significantly from MOE measured on the sections in tension and bending.