METHODS 



The extent animals and other biological and physical factors influence ponderosa 

 pine seed development was studied during the 33-month period extending from initial 

 ovulate bud formation until seeds are developed, disseminated, and ready to germinate. 

 Stands composed of ponderosa pine and Douglas- fir at Bluesky Creek, Dunn Creek, and But 

 ler Creek east of Libby in northwestern Montana provided the necessary study conditions 

 Based on the Daubenmires ' (1968) ecological habitat system, the areas were classified: 



Bluesky Pseudotsuga menziesii/Physocarpus malvaceus 



Dunn Pseudotsuga menziesii/Arctostaphylos uva-ursi 



Butler Pseudotsuga menziesii/Calamagrostis rubesoens 



Effects of Animals on Cones 



Eight sample trees were selected for study of factors influencing cones during 

 their 2-year development period. These trees averaged 20 inches in diameter at breast 

 height (ranging from 15 to 24 inches) ; they were randomly selected in a partially cut- 

 over ponderosa pine stand at Bluesky. In the upper portion of the crowns, 100 branches 

 (10 to 15 per tree) were marked and sampled repeatedly throughout the study period. 

 Losses of buds, conelets, and mature cones were described by cause and number for each 

 of these stages. Four successive cone crops, maturing in 1953 through 1956, were 

 measured four to seven times during each of their 2-year cone development periods. 



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