Tree rings of Scots pine (Pinus sylvestris L.) as a source of information about past climate in northern Poland

Scots pine (Pinus sylvestris) is a very common tree in Polish forests, and therefore was widely used as timber. A relatively large amount of available wood allowed a long-term chronology to be built up and used as a source of information about past climate. The analysis of reconstructed indexed values of mean temperature in 51-year moving intervals allowed the recognition of the coldest periods in the years 1207–1346, 1383–1425, 1455–1482, 1533–1574, 1627–1646, and 1694–1785. The analysis of extreme wide and narrow rings forms a complementary method of examining climatic data within tree rings. The tree ring widths, early wood and late wood widths of 16 samples were assessed during the period 1581–1676. The most apparent effect is noted in the dry summer of 1616. According to previous research and our findings, temperature from February to March seems to be one of the most stable climatic factors which influenced pine growth in Poland. Correlation coefficients in the calibration and validation procedure gave promising results for temperature reconstruction from the pine chronology

A gastruloid model of the interaction between embryonic and extra-embryonic cell types

Biological and Soft Matter Physic

Climatic conditions of the radial increment of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) in Poland

This paper descibes a study on relationships between radial increments of Douglas fir trees and such climatic factors as air temperature and precipitation. The described research encompasses analyses of 50 partial populations of the species growing in Poland

Dendroclimatic regions of Douglas fir Pseudotsuga menziesii (Mirb.) Franco in western and northern Poland

This study concerned 26 forest stands with Douglas fir situated in Lower Silesia, Great Poland, Pomerania, Warmia and Masuria. Each stand was represented by 24 trees. From each tree an increment core was taken by Pressler’s borer. The principal components analysis showed that the first three principal components accounted for 73% of the variation of chronologies in total. The first principal component was the most convergent with the mean air temperature curve for January–March, the second with the total precipitation for June–August, and the third with the mean temperature for June–August. The first principal component always integrated the chronologies and decided on a similar rhythm of changes in the tree-ring widths. The annual variation of tree-ring widths was also affected by precipitation in summer (June–August), but this differentiated the chronologies. This was reflected by the dispersion of chronologies in respect to the eigenvectors of the second principal component. The third principal component also differentiated the chronologies. Separate groups were formed by the most eastern and the most western localities of the territory under investigations. Thus the Douglas fir growth reactions were mainly affected by the thermal and pluvial conditions of summer and, to a lesser, degree by the thermal conditions of winter. On the basis of these results it was possible to distinguish the dendroclimatically homogeneous regions in western and northern Poland