Overall, the seedlings produced by local pollen were taller than those produced 

 with pollen from the north aspect plots but the differences were not significant. For 

 the south aspect plots, local pollens produced seedlings significantly taller than those 

 produced by the north aspect pollens. On the north aspect plots, pollen from one of the 

 other north plots usually produced taller seedlings than did local pollen. 



Among the north aspect Marble Creek plots, seedlings from the low plot were tallest 

 but pollen from the plot produced the shortest seedlings when used on trees in other 

 plots. For the high plot, the results were the opposite (seedlings from the plot trees 

 were short but pollen from the plot produced tall seedlings when used elsewhere). Such 

 reversals were probably the result of large amounts of within-plot variability coupled 

 with the small numbers of trees chosen to be pollen or seed parents in any one plot 

 rather than resulting from plot interactions. 



Natural selection study. --In this study only growth during the fourth growing season 

 was measured and analyzed (tables 8 and 9) . The mean growth of the 4 high-elevation 

 stands was significantly less than that of the 6 low-elevation stands (10.8 cm vs. 

 11.8 cm). However, the best high-elevation stands grew more than the poorest low- 

 elevation stand. Among the 6 low-elevation stands, the 4 fastest growing ones differed 

 significantly from the slowest growing one. 



Even though the differences between elevational groups and among stands were signif- 

 icant, the bulk of the genetic variation (61 percent) was associated with differences 

 among trees within stands. Of the remaining genetic variation, 28 percent was due to 

 elevational differences and 11 percent to differences between stands within elevational 

 zones. Overall, 62 percent of the variation was related to variation among seedlings 

 from the same tree, 2 percent to block interactions, and 36 percent to genetic variation. 



Table S . --Fourth year height growth of seedlings in the natural selection study 



Stand : 



Elevational 

 zone ^ 



: Growth : 



Range of : 

 family means : 



Number of 

 families 

 in top 10% 











- Centimeters 









Beaver Creek pole 



Low 



12 



4 



a2 



8 



8-15 



.4 



12 



Crystal Creek 



Low 



12 



2 



a 



9 



3-14 



.9 



9 



Beaver Creek mature 



Low 



12 



2 



a 



8 



3-16 



.1 



12 



Montford Creek 



Low 



11 



9 



ab 



9 



4-15 



.2 



7 



Fighting Creek 



Low 



11 



7 



abc 



9 



3-16 



.4 



3 



Rescue Creek 



High 



11 



4 



bed 



8 



2-14 



.8 



3 



Bertha Hill 



High 



11 



1 



cd 



7 



8-14 



.7 



1 



Elk Creek 



Low 



10 



9 



cd 



8 



2-13 



. 7 



1 



Boulder Creek 



High 



10 



8 



cd 



8 



0-14 



.9 



2 



White Rock 



High 



10 



6 



d 



7 



5-13 



.0 







Low = below 1,000 m, high = above 1,250 m. 



Means not having a letter in common differ at the 5 percent level of significance. 



13 



