Dendroclimatic investigations of Pinus sylvestris L. in the subArctic boreal forests

The aim of the study was to assess the influence of climatic factors on the growth of pine trees in the boreal forests of the sub-Arctic zone, and to identify environmental conditions for which it is possible to obtain tree chronologies containing a climate signal. Most suitable for dendrochronological analysis are the composite data series on pine stands sparsely growing in over-moistured conditions, as these have the highest sensitivity coefficient. In bilberry pine forests, stress index is low despite the proximity to the pulp and paper mill, recreational load, and improvement felling. The pine stands on wetlands show the average stress index. In conditions of anthropogenically caused air pollution, the tree-ring chronologies for pine growing on wetlands are characterized by increased levels of autocorrelation of the first order, which requires such pine stands be excluded from standardization process. Moderate correlation of growth indices, with precipitation in May and June, was revealed in the bilberry pine forests which underwent thinning. In the remaining sample plots, the relationship between the growth indices and the temperatures and precipitation of individual months may be weak or absent.