Search

Abstract: Norway spruce trees grown outside their natural range were intensively studied in terms of their adaptability to increased late winter temperature. A total of 708 cores of Norway spruce were taken from 35 sites throughout northwestern and western Poland at sites outside or at the margin of its natural range. Clustering reveals that research sites are grouped geographically. The mean ring widths, however, are similar among the three regions. The relationships between tree growth and temperature together with precipitation are comparable to those in lower elevations in Central and Eastern Europe and southern latitudes in Scandinavia. In total, 18% of the single correlations for all months were significant at p < 0.05. The generally positive precipitation effect was found for all months except January. Temperature had mixed effects on ring width. Higher temperatures in late winter and early spring increased ring width (13% of all significant correlations). High summer temperatures in both the previous and the current year, on the other hand, generally had a negative impact on tree-ring width during the growing season. On most of the sites, the observed long-term trend for increasing temperatures in February and March had no significant negative influence on tree growth. Also the effect of extreme weather events was taken into account. In 1994 and 1995 the wider rings were mostly observed in humid sites from southwestern Poland. In selected time spans, growth recovery following extreme weather events is particularly strong. [Copyright &y& Elsevier]

Abstract: Tree ring width (TRW), maximum (MXD), mean (MED) and minimum (MID) wood density were investigated in samples from the vicinity of the Tuchola Forest Biosphere Reserve (Northern Poland) in an attempt to distinguish the relative importance of climate and insect attack on the growth of Norway spruce. Selected climate parameters were used for a multiple regression to predict tree-ring width during insect outbreaks. This also used AICc for model selection. Additionally, k-means clustering was then used to group the yearly data of TRW, MXD, MID and the data of insect outbreaks. The respective climate data and data on insect outbreaks during the years 1962–1996 revealed a strong influence of May precipitation on TRW and insect outbreaks on MID. Missing tree rings or narrow rings and lower MXD together with higher MID might indicate increased insect activity. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

Abstract: The effects on tree growth of both climatic and non-climatic variables were investigated in relation to dune dynamics at three sites on the Czolpinska dune in the Slowinski National Park, Poland where aeolian sediments are invading a forest of Scots Pine (Pinus sylvestris L.). We found that where dune advance was relatively rapid, tree vitality declined after stem burial was over 1.9m, but where advance was under 1m/yr survival was remarkably increased, one tree survived, albeit with thinning needles, after an estimated 11.4m burial. Below sand-surface stem discs, cut 0.5m apart, from a heavily suppressed tree revealed a difference in narrow-ring reactions of up to 2years over a 2m burial distance; the discs also showed a time lag of 4years before compression wood formation. Consequently, when estimating sand-movement rates we discounted compression wood reactions; we also excluded climatic events and pest infestations. The remaining data supplied a sand-advance rate at Site 1 from 2.4 to 3.5m/yr. At Site 2, rates were from 1.2 to 2.5m/yr, with a direct measurement of 0.3m/yr between 2006 and 2007. At Site 3 rates were from 0.3 to 1.2m/yr, with dune migration here virtually at a standstill over the last seven years. Direct measurement of sand movement (3.03m/yr) at Site 1 was slower than the lowest rate (3.5m/yr) previously recorded by Borówka (1980) for the larger dune system. [Copyright &y& Elsevier]