Lund University Publications

Growth dynamics of tree-line and lake-shore Scots pine (Pinus sylvestris L.) in the central Scandinavian Mountains during the Medieval Climate Anomaly and the early Little Ice Age

• Mark

Abstract

Trees growing at their altitudinal or latitudinal distribution in Fennoscandia have been widelyused to reconstruct warm season temperatures, and the region hosts some of the world’slongest tree-ring chronologies. These multi-millennial long chronologies have mainly beenbuilt from tree remains found in lakes (subfossil wood from lake-shore trees). We used aunique dataset of Scots pine tree-ring data collected from wood remains found on a mountainslope in the central Scandinavian Mountains, yielding a chronology spanning over much ofthe last 1200 years. This data was compared with a local subfossil wood chronology with theaim to 1) describe growth variability in two environments during the Medieval ClimateAnomaly (MCA) and the early Little... (More)

Trees growing at their altitudinal or latitudinal distribution in Fennoscandia have been widelyused to reconstruct warm season temperatures, and the region hosts some of the world’slongest tree-ring chronologies. These multi-millennial long chronologies have mainly beenbuilt from tree remains found in lakes (subfossil wood from lake-shore trees). We used aunique dataset of Scots pine tree-ring data collected from wood remains found on a mountainslope in the central Scandinavian Mountains, yielding a chronology spanning over much ofthe last 1200 years. This data was compared with a local subfossil wood chronology with theaim to 1) describe growth variability in two environments during the Medieval ClimateAnomaly (MCA) and the early Little Ice Age (LIA), and 2) investigate differences in growthcharacteristics during these contrasting periods. It was shown that the local tree-line duringboth the MCA and early LIA was almost 150 m higher that at present. Based on living pinesfrom the two environments, tree-line pine growth was strongly associated with mid-summertemperatures, while the lake-shore trees showed an additional response to summerprecipitation. During the MCA, regarded to be a period of favourable climate in the region,the tree-ring data from both environments showed strong coherency and moderate growthvariability. In the early LIA, the two chronologies were less coherent, with the tree-linechronology showing more variability, suggesting different growth responses in the twoenvironments during this period of less favourable growing conditions. Our results indicatethat tree-ring width chronologies mainly based on lake-shore trees may need to be reevaluated. (Less)