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Ref ID: 28964
Ref Type: Journal Article
Authors: Helama, Samuli
Vartiainen, Matti
Kolstrom, Taneli
Peltola, Heli
Merilainen, Jouko
Title: X-ray microdensitometry applied to subfossil tree-rings: growth characteristics of ancient pines from the southern boreal forest zone in Finland at intra-annual to centennial time-scales
Date: 2008
Source: Vegetation History and Archaeobotany
Abstract: A collection of subfossil wood of Pinus sylvestris (Scots pine) was exposed to X-ray densitometry. The collection of 64 samples from the southern boreal forest zone was dendrochronologically cross-dated to a.d. 673-1788. Growth characteristics were determined by performing density profiles including the following parameters: minimum density, earlywood and latewood boundary density, maximum density, earlywood width, earlywood density, latewood width, latewood density, annual ring width and annual ring density. Seven out of the nine parameters were found to contain non-climatic growth trends and six were found to be heteroscedastic in their variance. Tree-specific records were indexed, to remove the non-climatic growth trends and stabilize the variance, and combined into nine parameter-specific tree-ring chronologies. Growth characteristics of the pines changed in parallel with the generally agreed climatic cooling from the Medieval Warm Period to the Little Ice Age: pine tree-rings showed decreasing maximum densities from the period a.d. 975-1150 to a.d. 1450–1625. A concomitant change in the intra-annual growth characteristics was detected between these periods. The findings indicate that not only the trees growing near the species’ distributional limits are sensitive to large-scale climatic variations but also the trees growing in habitats remote from the timberline have noticeably responded to past climate changes.
Date Created: 11/30/2010
Volume: 17
Number: 6
Page Start: 675
Page End: 686