Rehfeldt, Gerald E. 



1979. Variation in cold hardiness among populations of Pseudotsuga 

 menziesii var. glauca. USDA For. Serv. Res. Pap. INT-233, 11 p. 

 Intermt. For. and Range Exp. Stn. , Ogden, Utah 84401. 



Cold hardiness in 2-year-old seedlings representing 51 populations 

 of Pseudotsuga menziesii var. glauca developed at a rate associated with 

 the minimum temperature. During the early stages of cold acclimation, 

 variation in the hardiness of populations was related to geographic and 

 ecologic factors of the seed source. Multiple regression analyses 

 accounted for 38 percent of the variance among populations and showed 

 that populations of greatest hardiness in early autumn were from rela- 

 tively high latitudes and high elevations. But, during late stages of 

 cold acclimation, variation in hardiness among populations could not be 

 related to factors of the seed source. 



KEYWORDS: cold hardiness, cold acclimation, ecological genetics, 

 Pseudotsuga menziesii, seed zoning. 



Rehfeldt, Gerald E. 



1979. Variation in cold hardiness among populations of Pseudotsuga 

 menziesii var. glauca. USDA For. Serv. Res. Pap. INT-233, 11 p. 

 Intermt. For. and Range Exp. Stn., Ogden, Utah 84401. 



Cold hardiness in 2-year-old seedlings representing 51 populations 

 of Pseudotsuga menziesii var. glauca developed at a rate associated with 

 the minimum temperature. During the early stages of cold acclimation, 

 variation in the hardiness of populations was related to geographic and 

 ecologic factors of the seed source. Multiple regression analyses 

 accounted for 38 percent of the variance among populations and showed 

 that populations of greatest hardiness in early autumn were from rela- 

 tively high latitudes and high elevations. But, during late stages of 

 cold acclimation, variation in hardiness among populations could not be 

 related to factors of the seed source. 



KEYWORDS: cold hardiness, cold acclimation, ecological genetics, 

 Pseudotsuga menziesii, seed zoning. 



