Updated Findings in the Determination of the Mechanical Properties of the Wood of Western Juniper ( Juniperus occidentalis Hook . ) Report of 3 September 2008

As previously reported, wood of western juniper, Juniperus occidentalis Hook, was collected from nine locations throughout its range in northern California, south-central and central Oregon. Trees for testing were selected, in part, by their stem form and ability to provide useable test material. Trees of unusual size and form were not, however, selected for test trees, but were bypassed in favor of those individuals that best represented the typical size and form of the potential commercially-sized trees in a particular area. The locations were chosen on the basis of the anecdotally-reported differences in stem form and perceived strength and durability from the eight geographic areas. Each general area, Alturas, California, and Klamath Falls, Sisters and Burns regions of Oregon, were chosen for the volume of standing juniper, favorable tree form and size, and presence of stands showing either relatively modest or large growth rates and stem forms. A total of 42 trees were selected and harvested, and nine-foot bolts bucked and shipped to the mechanical properties laboratory at the University of Montana School of Forestry. Specimens were extracted and tested, according to ASTM Standard D-143-95, “Standard Methods of Testing Small Clear Specimens of Timber”. Interim results have been periodically reported to enable the wood products industry in the areas where western juniper grows to gain a more complete picture of the mechanical properties of this species, as well as information on its specific gravity and shrinkage from the green condition. Data for specific properties have been distributed to users and potential users of the wood of this species for a variety of products, including house logs, structural timbers, glued panels, and composite products.