the 760 m Clearwater collection grew poorly at the low- and mid -elevation sites at Canyon 

 but well at the high site. In contrast, at PREF they grew well at the low- and mid- 

 elevation sites but poorly at the high site. However, these fluctuations are rather 

 small--only 2 or 3 cm (5 percent) above or below the site mean--and, so far at least, 

 appear more accidental than the result of specific tree-site interactions. 



When the overall variability across sites within test regions was analyzed (table 6), 

 the variation associated with trees within elevational zones was still predominant over 

 that for elevational zones or areas. The site x tree interaction effect was significant 

 at PREF. When the tree mean squares were tested against this interaction term rather 

 than the error mean squares, the tree effects were significant at only the 5 to 10 

 percent level. 



The average height of the seedlings over the three sites at PREF was essentially 

 the same as that for the Canyon sites but the range at PREF was much greater. Neither 

 group of sites shows a typical spread of conditions for the area. At PREF, growth and 

 survival at the mid-elevation site has been reduced due to poor site quality and resid- 

 ual competition resulting from site preparation problems. At Canyon, the low site 

 trees suffered from similar site preparation problems. 



Table 6. --Analyses of variance and percent of total variation for height of V-year-old 



seedlings of the elevational study oomhined over sites at Canyon and. PREF 









Canyon 



: PREF 



Source : 



d.f . 



: Mean 

 : square 



% of total 

 variation 



: Mean : 

 : square : 



% of total 

 variation 



Test sites^ 



2 



3,829 



4.9 



106,038 



52.2 



Replicates within sites 



12 



302 



1 . 1 



172 







Area 



1 



127 







493 







Site * Area 



2 



177 







658 



0.4 



Elevation within Area 



10 



290 



0.2 



278 







Site * Elevation 



20 



168 







101 







Rep * Area § Elev (Error 1) 



132 



149 



2.8 



188 



2.0 



Trees within Elevations 

 and Areas 



48 



212*2 



1.9 



283 



0.7 



Site * Tree 



94 



142 



2.1 



213** 



2.8 



Rep * Tree (Error 2) 



500 



111 







119 



1.5 



Within Plot 



3 



116 



87.0 



109 



40.4 



^Low, mid, and high elevation. 



2* and ** indicate significance at the 5 percent and 1 percent level, 

 respectively. 



^At Canyon d.f. = 1,001, at PREF d.f. = 1,694. 



11 



