ABSTRACT 



At eight locations in western Montana some factors limiting 

 the success of ponderosa pine natural regeneration were identi- 

 fied. During the 45-month period from ovulate bud formation 

 until the seedlings were 1 year old, the potential decreased a 

 thousandfold. Losses were attributed mainly to abortions and 

 squirrel cutting during the 2-year cone development period and to 

 mice and chipmunks during the 8-month period from seedfall to 

 germination. Mineral soil seedbed enhanced the survival of 

 young seedlings. These results showed that cone production in 

 50-year-old trees was temporarily stimulated by girdling, that 

 squirrel losses can be eliminated by banding trees with metal 

 strips, and that prospective cone crops can be detected early 

 enough to permit the coordination of site preparation with an 

 adequate seed crop. 



