RESEARCH SUMMARY 



In nursery and field tests representing five different studies, most of the 

 variation in height growth or other traits in any one test area was among se- 

 edlings within family plots. Of tne useable genetic variation in those traits, 

 most (60-90 percent) was related to differences among the parent trees within 

 stands. The remaining genetic variation was spread among geographic areas, 

 elevational zones, or stands within these categories. When differences among 

 the latter catagories were significant, usually no pattern in the variation was 

 apparent. Thus, although seedlings within families and family means within 

 stands vary considerably, the lack of differences among stand means, or those 

 for broader geographic areas, and the absence of distinct variation patterns 

 suggests that inland western white pine is fairly uniform. However, seedhngs 

 from high-elevation parents (generally 1, 375 m or higher) were significantly 

 shorter than those of low- and mid-elevation parents in some low- or mid- 

 elevation tests. Even when elevational effects were not significant very few 

 high elevation families were among the tallest. Growth results to date indicate 

 that only two seed zones are needed in north Idaho — a low zone and a high zone 

 generally separated at 1,375 m. Within the lower zone, trees with good 

 growth potential can be found in nearly all stands. 



