Approximately one-third of all control -pol linated 

 cones, whether cross- or se If -pol linated, failed to 

 reach maturity. Since losses of cones due to insects, 

 rodents, or breakage were known and minimal, losses 

 of control -pol linated cones were almost entirely due 

 to abortion of cones during development. Sarvas (1962) 

 suggested that conelet abortion in pines is associated 

 with high ovule abortion rates accompanying poor polli- 

 nation. Conelet abortion of pines also appears to be 

 associated with soil moisture stresses during the period 

 of conelet elongation in P. monticola 2 and P. vadiata 

 D. Don (Pawsey 1960) . 



SUMMARY AND CONCLUSIONS 



Between the ages of 30 and 50, western white pines 

 average 28 cones per year. Each cone contains about 

 104 filled seeds which means that each tree produces 

 about 3,000 filled seeds; however, tremendous variations 

 occur. Annual production of cones is highly variable. 

 Also, within a given seed year certain localities and 

 individual trees within localities vary greatly in 

 productivity. Of additional importance is the direct 

 relationship between the proportion of filled seed 

 and the size of the cone crop. Increased efficiency 

 in seed collection can be realized by avoidance of 

 low-yielding localities, trees and seed years. Also, 

 by collecting only in high-yielding localities, cone and 

 seed procurement can be maximized with a minimum of 

 effort. This is particularly true when cone production 

 is generally low. 



It is further noteworthy that once techniques 

 are mastered and proper timing is ascertained, yields 

 derived from controlled pollinations of western white 

 pine almost equal those of wind pollination. 



2 Ibid. 



11 



