Timing of shedding seeds and cones, and production in different stands of Scots pines at Abernethy Forest, Scotland

A study was carried out over 11 seed years on the timing ofshedding of seeds and cones, and annual seed fall and cone productionin three stands of native Scots pinewood and a Scots pine plantationin Abernethy Forest, Scotland. Peaks in seed fall took placemainly in May, and cones were shed mainly between June and August.There were few residual seeds remaining in shed cones. Synchronizedpeaks in seed fall and cone production (mast years) took placeat 3-year intervals across the different stands. The differencebetween cohorts of high and low cone production ranged fromfactors of 5 to 20 among sites. Coefficients of variation forcone production ranged from 62 to 84 per cent among sites. Therewere no significant differences in cone production among sites,but there were site-related differences in seed fall. The largercanopy cover in the plantation probably accounted for the higherseed fall per square metre there, though variations in the amountof seed eaten by birds and mammals may also have been important.Canopy cover needs to be considered when converting cone densitiesunder crowns to cone density per unit of woodland area. A similarcalculation is difficult for seeds because they are lighterthan cones and many fall outside the area under the crowns.The results are discussed in relation to the potential for treeregeneration and the availability of food for birds and mammalsprior to seed dispersal.