Spatio-temporal variability in Scots pine radial growth responses to annual climate fluctuations in hemiboreal forests of Estonia (original) (raw)
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Dendrochronologia, 2004
This work seeks to analyse the importance of summer-temperatures on the tree-ring growth of Scots pine (Pinus sylvestris L.) during the past three centuries. Three living-tree chronologies, subfossil pine chronology and one composite tree-ring chronology were constructed from latitudinal and altitudinal forest-limits of pine in northern Finland and compared with meteorological data comes from three localities. These data include early instrumental temperature observations from 18 th and 19 th centuries. The modern meteorological data covers the period from 1860 to present. Response functions were derived by means of Pearson correlations using five subperiods as follows: 1738±1748, 1802±1822, 1825±1835, 1861±1926 and 1927±1992. It was demonstrated that the correlations between ringwidths and midsummer (July) temperatures did not vary significantly as a function of time. Early-(June) and late-summer (August) mean temperatures were secondary in relation to midsummer temperatures in controlling the radial growth. Early-summer temperatures governed pine radial growth most clearly during the 19 th century, whereas late-summer temperatures had strongest influence on ring-widths during the 18 th century and later part of the 20 th century. There was no clear signature of temporally reduced sensitivity of Scots pine ring-widths to midsummer temperatures over the periods of early meteorological observations. Subfossil pine chronology, constructed using pines recovered from small lakes along the forest-limit zone, showed a consistent pattern of response to summer-temperatures in relation to living-tree chronologies.
Regional climatic signals in Scots pine growth with insights into snow and soil associations
Dendrobiology, 2013
We performed climatic assessments of Scots pine growth variations in Finland over recent decades by their tree-ring series and comparing growth variations to those observed in meteorological records. Tree-ring indices showed non-significant growth trends over roughly the past four decades (1972-2007). The observed growth variability was explained by connexions to the midsummer (July) climate (temperature and, likely, cloudiness) in the north and to the spring (April) soil temperatures in the south. Tree growth was negatively associated with snow depth at the beginning of dormancy (in November, previous to the corresponding growth year) in the south and during the growing season start (May) in the north. Thus, these analyses emphasized the relevance of snow and soil data, which have usually been overlooked in studies of associations between climate and tree-ring changes.
Silva Fennica, 2000
Lindholm, M., Lehtonen, H., Kolström, T., Meriläinen, J., Eronen, M. & Timonen, M. 2000. Climatic signals extracted from ring-width chronologies of Scots pines from the northern, middle and southern parts of the boreal forest belt in Finland. Silva Fennica 34(4): 317-330.
Response of Scots Pine (Pinus sylvestris L.) Radial Growth to Climate Factors in Estonia
DESCRIPTION The following research paper analyzes Scots pine (Pinus sylvestris L.) radial growth responses to climatic factors in mesotrophic and heath forest site types in Estonia. Increment cores from 889 trees from 119 plots of the network of research plots were used and chronologies for mesotrophic and heath forest site types of Scots pine were constructed. The relationship between climatic factors and the radial growth of Scots pine was characterized by correlation coefficient; also pointer year analysis, Cropper method was applied to single tree series. Cropper values were calculated; extreme negative and positive pointer years were identified. According to analyses, 1940 and 1985 were the most significant negative pointer years among different sites; and significant positive years were 1945, 1946, 1989, and 1990. Extreme Cropper values indicated significant positive correlation with the monthly mean temperature in winter (January, February) and early spring (March, April) bef...
Growth response of Scots pines in polar-alpine tree-line to a warming climate
Forest Ecology and Management, 2017
Coniferous trees at the alpine and polar tree lines of the Northern Hemisphere represent the outermost limit of their ecological range. Under such conditions, even small temperature variations may cause growth responses, which therefore can be used as indicators for changing environmental conditions. In this study we analysed the radial growth of Scots pine (Pinus sylvestris L.) along a latitudinal and altitudinal gradient at six locations in the polar and alpine tree-line ecotone in Finnish Lapland. We evaluated the effect of climatic trends on pine growth in relation to tree age and region, specifying a northern and a southern region in the study area. We found a response of Scots pine to climatic variations until the 1980s, but not to the current warming period. Increasing growth trends could be detected since 2000 in the radial growth of southern located trees, predominantly of juvenile ages, while the northern trees did not respond significantly to the current warming. In the north recent warmer and wetter conditions during winter time, inducing snow loads, wind damages, diseases and frost damages possibly masked the benefits of warmer conditions. The missing link between warming and radial growth would affect the use of tree-rings as proxy for past climate and for predictions for forest extension in polar-alpine tree-line sites.
International Journal of Biometeorology, 2006
The relationships between climatic variables and Scots pine (Pinus sylvestris L.) growth and needle dynamics were studied in three stands in Estonia and in four stands located near the northern timberline in Lapland. The trees sampled in Estonia had low correlations with the analysed climatic variables (air temperature, precipitation and indices of atmospheric circulation). Moreover, the weak cross-correlation of the time-series of the Estonian sample trees indicated that Scots pine is affected mainly by local factors in that region. In Lapland, however, height increment and needle production correlated strongly among trees within a stand (mean r =0.45 and 0.46, respectively) and between stands (r =0.32 and 0.37). Radial increment also showed a high inter-correlation among the trees within a stand in Lapland (r =0.45). Both height increment and needle production were strongly influenced by the temperature regime of the previous summer in Lapland (mean r =0.64 and 0.64, respectively). Radial increment was correlated with the mean July temperature of the current year (mean r =0.29). The correlations between the indices of atmospheric circulation and tree attributes were weak, while the strongest correlation was between the Ponta Delgada NAO index (PD-NAO) and height increment and needle production in Lapland. Height increment, needle production and radial increment have increased since the 1990s in the trees growing in Lapland. This may indicate a positive effect of climate warming on tree growth in Lapland. In Estonia, where climatic conditions do not limit tree growth, the climate warming seems not to directly influence the growth and needle dynamics of Scots pine.