Seed dispersal
Seed dispersal begins after cone scales reflex with cone maturation in the late summer or early fall of the year of formation. Cones open at moisture contents of 45% to 70% and specific gravities of 0.6 to 0.8 (Cram and Worden 1957, Zasada 1973, Winston and Haddon 1981). Weather affects both the initiation and pattern of seed dispersal (Nienstaedt and Zasada 1990), but cone opening and the pattern of seed dispersal can vary among trees in the same stand (Zasada 1986). Even after dispersal has begun, cold, damp weather will cause cone scales to close; they will reopen during dry weather. Most seed falls early rather than late, but dispersal may continue through fall and winter (Zasada 1986), even into the next growing season (Rowe 1953). Seed dispersal occurs mainly in late summer or early fall (Waldron 1965).