Climate has a larger effect than stand basal area on wood density in Pinus ponderosa var. scopulorum in the southwestern USA

Context: Forest restoration treatments in the U.S. Southwest are generating large quantities of small-diameter logs. Due to negative perceptions about ponderosa pine wood quality, this material is often seen as a “waste disposal” problem rather than a high-value resource. Aims: Our objective was to understand more about variation in southwestern U.S. ponderosa pine wood density, an important indicator of wood quality. Specifically, we investigated the effect of stand basal area on wood density, and the effect of annual and quarterly climatic variation on wood density. Methods: We collected samples from 54 trees grown at six different basal area levels from a replicated stand density experiment. Pith-to-bark strips were used in an X-ray densitometer to obtain annual density and growth measurements from 1919 to the present