Ecological adaptations in Douglas-fir (Pseudotsuga menziesii var. glauca ). IV. Montana Idaho near the Continental Divide

Journal Article

Transfer Guideline: Recommendation

Seventy-seven seedlings populations of Douglas-fir (Pseudotsuga menziesii var. glaucas ) sampled from near the Continental Divide in Idaho and Montana exhibited pronounced genetic differences when compared in three common environments. Differentiation involved several traits several traits that are components of an annual developmental cycle that must be completed within a growing season of finite length. Consequently, elevational and geographic clines of genetic variation tend to parallel variation in the length of the growing season at the seed source. Such clines suggest that maladaptation in artificial reforestation can be controlled by limiting the transfer of seeds. While geographic transfers can be relatively liberal, elevational transfers should be limited to -+90 m (300f t) from the seed source at elevations below 1,400 m (4,600 ft), to -+125m (410ft) for elevations between 1,400 and 2,000 m (4,600 and 6,550 ft), and -+200m (560ft) for devations above 2,000 m (6,550 ft).