%0 Research article
%T Natural development of stand structure in peatland Scots pine following drainage: results based on long-term monitoring of permanent sample plots
%A Sarkkola, Sakari
%A Hökkä, Hannu
%A Penttilä, Timo
%D 2004
%J Silva Fennica
%V 38
%N 4
%R doi:10.14214/sf.408
%U https://silvafennica.fi/article/408
%X We studied the dynamics of stand structure on drained peatland sites in  Scots pine dominated stands untreated with thinnings. The data consisted  of consecutive stand measurements in 10 permanent sample plots where  the monitoring periods varied from 29 to 66 years. We assumed that the  stand’s structural development was driven by the natural processes of  regeneration, growth, and mortality, all related to inter-tree  competition within the stand. The DBH distributions of live and dead  trees at different times of post-drainage stand development – smoothed  by Weibull function – were analysed to characterise the change in stand  structure. The initial uneven-sized structure of the natural,  widely-spaced stands became more uneven during the first decades  following drainage due to enhanced regeneration. Later, as stand density  and mean tree size continuously increased, the DBH distributions  approached bell-shaped distributions. Accordingly, the suppressed trees  showed their highest mortality rate during the first decades, but the  peak of the mortality distribution shifted to larger trees along stand  succession. The change in structure was faster in southern Finland than  in northern Finland. We assumed the changes in stand dynamics reflected  increased inter-tree competition, initiated by enhanced site  productivity and increased stand stocking resulting from the ditching  operation.