Rehfeldt, G. E. Ecological genetics of Pinus contorta in the upper Snake River 

 Basin of eastern Idaho and Wyoming. Research Paper INT-356. Ogden. UT: 

 U.S. Department of Agriculture, Forest Service, Intermountain Research 

 Station; 1986. 9 p. 



Genetic differentiation of 60 populations of Pinus contorta primarily from 

 eastern Idaho and western Wyoming was studied in field, greenhouse, and 

 laboratory tests. Analyses of variables reflecting growth potential, morphology, 

 cold hardiness, and periodicity of shoot elongation revealed population differen- 

 tiation for a variety of traits. Regression models related as much as 83 percent 

 of the variance of population means to the elevation and geographic location of 

 the seed source. For genetic variation to be arranged along relatively steep 

 environmental dines implies pronounced adaptive differentiation. As a result, 

 seed transfer in reforestation should be restricted severely if maladaptation is 

 to be controlled. 



KEYWORDS: microevolution, adaptation, population differentiation, seed zones, 

 seed transfer 



INTERMOUNTAIN RESEARCH STATION 



The Intermountain Research Station provides scientific knowledge and 

 technology to improve management, protection, and use of the forests and 

 rangelands of the Intermountain West. Research is designed to meet the 

 needs of National Forest managers, Federal and State agencies, industry, 

 academic institutions, public and private organizations, and individuals. 

 Results of research are made available through publications, symposia, 

 workshops, training sessions, and personal contacts. 



The Intermountain Research Station territory includes Montana, Idaho, 

 Utah, Nevada, and western Wyoming. Eighty-five percent of the lands in 

 the Station area, about 231 million acres, are classified as forest or range- 

 land. They include grasslands, deserts, shrublands, alpine areas, and 

 forests. They provide fiber for forest industries, minerals and fossil fuels for 

 energy and industrial development, water for domestic and industrial con- 

 sumption, forage for livestock and wildlife, and recreation opportunities for 

 millions of visitors. 



Several Station units conduct research in additional western States, or 

 have missions that are national or international in scope. 



Station laboratories are located in: 



Boise, Idaho 



Bozeman, Montana (in cooperation with Montana State University) 

 Logan, Utah (in cooperation with Utah State University) 

 Missoula, Montana (in cooperation with the University of Montana) 

 Moscow, Idaho (in cooperation with the University of Idaho) 

 Ogden, Utah 



Provo, Utah (in cooperation with Brigham Young University) 

 Reno, Nevada (in cooperation with the University of Nevada) 



