Identification of the wood of the soft pines of western North America

Abstract

A method is described for identifying the woods of the soft pines of western North America: namely, western white pine (Pinus monticola Doug!.), sugar pine (P. lambertiana Doug!.), limber pine (P. flexilis James) and white bark pine (P. albicaulis Engelrn.). Unique features of P. f1exilis and P. albicaulis are the presence of crystals in the resin canals and dimple marks on tangentially split surfaces, respectively. P. monticola and P. lambertiana cannot be separated absolutely and judgement must be exercised based on a number of macroscopic and microscopic observations. One of the most useful of these observations appears to be the nature of the cross-field pitting between ray parenchyma and longitudinal earlywood tracheids. If thorough examination of a radial section reveals on-Iy a few examples of 3 pits per cross-field in the first formed earlywood tracheids then the sampie is probably P. monticola. However, if a few instances of 4 or 5 pits per cross-field are observed, probably the sampie is P. lambertiana. Resin canal diameter measurements do not provide a viable method of distinguishing these two species.