Cone yields also varied among individual trees 

 within localities (table 2). Differences in cone pro- 

 duction of individual trees within localities were 

 directly proportional to the effect of the seed year 

 just as were differences in yield among localities. 

 Moreover, differences in cone yield per year among 

 individual trees depended on the overall yield of the 

 locality. Although cone production by trees in high- 

 yielding localities differed by as much as 100 cones 

 per tree for each year, trees within localities of low 

 mean yield showed little difference in production. 

 Thus, each locality contained trees that characteris- 

 tically produced few cones, even in good seed years; 

 differences among localities apparently resulted from 

 varying proportions of trees that produced large crops 

 of cones in generally high-yielding years. 



Of the exogenous factors that affect cone yield, 

 the one that cannot be assessed at this time, due to 

 lack of data, is the influence of microsites on the 

 yield of trees within localities. However, other 

 factors can be assessed; tree age, elevation, and 

 latitude can be related to mean cone yield by correla- 

 tion analyses (table 3) . Although unequal sampling 

 and possible intercorrelations among age, elevation, 



Table 3 .- -Correlation of tree age* tree elevation* and 

 locality latitude with cone yield of: individual 

 trees; trees within localities ; and localities 



Tree Locality 

 Cone yield Tree age elevation latitude d.f. 



Correlation coefficient s r 



Individual trees 0.33** 0.42** -- 177 



Trees within local- 

 ities (pooled r) .45** .44** 166 



Localities -- -- .66* 11 



**Significant at the 1 percent level of probability. 

 *Significant at the 5 percent level of probability. 



5 



