t 



Results 



Cone Mortality 



Following bud formation, the number of developing pine cones decreased continuously 

 until seed dissemination 2 years later. An average of only 6 percent of the ovulate 

 buds matured and shed seed (table 2). Four cone crops, one rated fair (1954) and three 

 rated poor (1953, 1955, and 1956), quantified these losses. 



The percentage of cone survival was highest following the formation of the largest 

 number of ovulate buds. The 1954 crop (rated fair) had 9 percent survival, but the 

 1955 crop (poorest of the 4 years) had no survival. 



Seventy percent of the potential cones aborted (table 2), 64 percent during the 

 first season and 6 percent during the second season. Squirrels reduced the potential 

 cone crop an additional 14 percent and all other factors caused an additional 10 

 percent loss. 



First Year of Development 



An average of only 27 percent of the potential cone crop survived the first year 

 of development. At the beginning of the first season, 5 percent of the buds failed to 

 open. Following this, 64 percent of the cones aborted during the first season. Causes 

 of these heavy losses from bud failure and abortion were not identified. Squirrel cut- 

 tings accounted for 2 percent of the first-year losses. Insects and other miscellaneous 

 factors accounted for the remaining losses. 



Second Year of Development 



Only 23 percent of the pine conelets that survived the first year persisted until 

 seedfall. During the second year an additional 6 and 12 percent of the potential cones 

 aborted or were cut by squirrels, respectively. Insects and other miscellaneous factors 

 accounted for the remaining losses. Consequently, only 6 percent of the buds matured 

 and released seed at the end of the second year of development. 



Table 2 .--Cause and amount of cone mortality during 

 the 2-year development period 



Year 



of 

 seed 

 maturity 



. Ovulate 

 buds 



Bud \ 

 failure 



Abortions 



Squirrel . 

 cutting 



Insect 

 loss 



. Miscel- 

 laneous 

 loss 



. Cones 

 . surviving 

 and 

 shedding 

 seed 





Number 







- - -Percent- 









1953 



292 





65 



24 



6 



2 



4 



1954 



648 



4 



79 



5 



1 



2 



9 



1955 



67 



24 



72 











4 







1956 



102 



19 



26 



47 



8 







1 



All years 



1,109 



5 



70 



14 



3 



2 



6 



3 



