Ecological genetics of Pinus contorta in the Upper Snake River Basin of eastern Idaho and Wyoming /

Genetic differentiation of 60 populations of Pinus contorta primarily from eastern Idaho and adjacent Wyoming was assessed in three studies involving (1) growth and development in field environments, (2) the periodicity of shoot elongation in the greenhouse, and (3) freezing tolerance in the laboratory.Genetic differentiation between populations was observed for traits that included 3-year height, leaf length, freezing tolerance, and the pattern of shoot elongation.Regression models related as much as 83 percent of the variation between populations to the elevation and geographic location of the seed origin.Elevational clines were particularly steep.Consequently, if maladaptation is to be controlled in artificial reforestation, seed transfer should be restricted severely for elevation but geographically may be relatively liberal.Detailed practical guidelines will be presented separately.