Phenotypic Variation Associated with Elevation in Western White Pine

Racial differentiation of Pinus monticola Dougl. associated with elevation was investigated on sample plots selected at elevations ranging from 2,500 to 4,600 feet. Periodic annual height growth was significantly less for trees at 4,600 feet than for trees at elevations ranging from 2,500 to 4,000 feet. Branch angle increased progressively and significantly with increasing elevation. Needle length and cone scale width and length between elevations differed significantly, but the pattern of variation was essentially random. For other attributes, including seed weight, no significant difference was found between elevations. There were highly significant and moderately strong correlations between many cone and seed traits. In general, cone and seed traits were not significantly correlated with growth rate or branch angle.