Progeny of many of the same parents used in the above studies were outplanted to 

 two additional sites for long-term evaluation. Rehfeldt and Steinhoff (1970] found that 

 at age 14 average growth at the two sites differed significantly and that the growth of 

 individual progenies differed significantly but the average growth of progenies from 

 different localities did not differ significantly. 



In order to obtain materials representative of a broader range of sites, Barnes 

 (1967) systematically collected seed and recorded data from trees in a series of eleva- 

 tional plots along several north Idaho streams. He reported finding significant dif- 

 ferences in periodic annual growth rate and branch angle that were related to eleva- 

 tional differences along one transect. Trees in plots from 760 m elevation to 1,220 m 

 grew at essentially the same rate, but those from 1,400 m and above were slower growing. 

 Branch angle changed progressively from low to high plots, with trees in the lower plots 

 having more ascending branches and those in the higher plots having more nearly hori- 

 zontal branches. Differences among plots were also found in needle length and cone 

 scale length and width, but the variation did not follow a pattern related to elevation. 



Some of the seed collected by Barnes was soim in a nursery trial in Michigan. 

 After 4 years of growth, total height of seedlings representing the various elevational 

 and latitudinal collection areas did not differ significantly (Townsend and others 1972] . 

 Seasonal growth rates differed, but they did not fit into a pattern related to elevation 

 or latitude. At a very low light level (130 lux) low-elevation seedlings (640 m) were 

 less efficient photosynthetically than higher elevation seedlings (1,065 m and 1,585 m) , 

 but at higher light levels (425 and 615 lux) differences were not apparent. 



MATERIALS AND METHODS 



This report will present and integrate results from five studies, as follows: 



1. Elevational study. --This study was started to further investigate the effects 

 of elevation (as indicated in Squillace and Bingham 1958) and possibly latitude on 

 seedling growth. Wind-pollinated seed for the test was collected from individual trees 

 in plots (stands) at 120 m to 180 m (mostly 150 m) elevational intervals in several 

 stream drainages in north Idaho. Although the collection locations were often along 

 streams, they were kept out of the stream bottoms where cold air drainage effects are 

 common. Five trees from each of 1 to 3 plots per elevation and drainage were included, 

 for a total of 225 trees in 45 plots (fig. 1). In the Trestle Creek drainage, the 

 plots within an elevational zone were close together (mostly within 0.5 km), but in the 

 other areas the plots were often several kilometers apart. Further details of plot loca- 

 tion for the Trestle Creek drainage were presented by Barnes (1967) . 



A nursery test for early growth and seedling traits was conducted for 3 years at 

 Moscow, Idaho. The seed were sown at a spacing of 5x10 cm in 10-tree row plots in 4 

 replicates. The growing medium was a mix of forest soil, sand, and peat moss in equal 

 proportions. The beds were watered and fertilized as needed to maintain satisfactory 

 growth. Annual height measurements were taken after growth v\fas completed. 



Field plantations have been established at the Priest River Experimental Forest 

 (PREF) and near the North Fork of the Clearwater River on the Canyon Ranger District 

 (Canyon) (fig. 1). In each area, 3 test plantations were established with an eleva- 

 tional separation of 300 m (800 m, 1,100 m, and 1,400 m at PREF and 900 m, 1,200 m, 

 and 1,500 m at Canyon). Aspect of the sites ranges from northeast to northwest. The 

 field tests contain representatives of nearly all the seed collection areas and eleva- 

 tion zones but do not contain representatives of all the plots within elevational zones. 



2 



