%0 Research article
%T Timing of seed dispersal in Pinus sylvestris stands in central Sweden
%A Hannerz, Mats
%A Almqvist, Curt
%A Hörnfeldt, Roland
%D 2002
%J Silva Fennica
%V 36
%N 4
%R doi:10.14214/sf.518
%U https://silvafennica.fi/article/518
%X The objective of the study presented here was to describe the variation  in timing of seed dispersal from Scots pine (Pinus sylvestris L.) seed  trees in central Sweden. Seeds were collected in traps at two sites, for  three years at one, and four years at the other . The traps were  emptied from March to August each year at 1–2 week intervals during the  main period of seed dispersal. The annual seed fall varied between  200 000 and 1.6 million seeds per hectare. The seed fall started in mid  to late April, shortly after the heat sum had started to accumulate. The  most intensive seed fall took place in early to mid May. The peak  period, when 50% of the total seed dispersal occurred, lasted for 18–28  days at the different sites and years. The variation in timing among  years seemed to be mainly due to climatic factors – high temperatures  promoted seed dispersal, for instance. The results may be useful for  planning the time of scarification to optimise the natural regeneration  of Scots pine. The data suggest that scarification in the spring, no  later than mid-May, would generally create a good seed-bed for most of  the current year’s seeds, whereas scarification in late May or June  would bury a large proportion of this cohort.