%0 Research article
%T Natural regeneration of Scots pine and Norway spruce close to the timberline in northern Finland
%A Juntunen, Vesa
%A Neuvonen, Seppo
%D 2006
%J Silva Fennica
%V 40
%N 3
%R doi:10.14214/sf.329
%U https://silvafennica.fi/article/329
%X Two different datasets were analyzed in order to clarify the factors  that affect regeneration success of Scots pine (Pinus sylvestris) and  Norway spruce (Picea abies) in the climatically extreme areas in  northern Finland. First, pine seed maturity and the number of cones in  the trees were investigated at five pairs of study sites during the  period 1997–2003. Secondly, the rate of seedling establishment and  seedling survival of Scots pine and Norway spruce were monitored and  compared among three different timberline zones (forest zone,  timberline, tree line) in 13 localities during the period 1983–1999. The  first study showed that both cone production (bud formation) and seed  maturity may be limiting factors for successful reproduction in the  climatically marginal habitats. Seed maturity correlated well with the  temperature sum of the summer, but variation in the number of cones had a  periodic component rather than strictly following the temperature sum  of the summer of bud formation. Monitoring surveys since 1983 showed  that pine and spruce regenerated more or less regularly in all the zones  during 1983–1999. However, seedling mortality of pines was much higher  compared to spruce. In general, initially small sized seedlings showed  higher mortality compared with larger ones. The results suggest that  besides restrictions in reproduction, stand dynamics in the timberline  habitats are strongly controlled by seedling mortality due to a variety  of causes.