Evidence on climatic variability and prehistoric human activities between 165 B.C. and A.D. 1400 derived from subfossil Scots pines (Pinus sylvestris L.) found in a lake in Utsjoki, northernmost Finland

• Published in: Bulletin of the Geological Society of Finland
• Main Authors: P. Zetterberg, M. Eronen, K.R. Briffa
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Society of Finland 1994
• Subjects: dendrochronology; subfossil tree; Scots pine (Pinus sylvestris L.); tree limit; forest history; lake-levels; climate change; Saami Iron Age; Late Holocene; Lapland; Finland; Geology; QE1-996.5; Ailigas; Fennoscandia; Northern Finland; Northern Sweden; saami; Utsjoki
• Online Access: https://doi.org/10.17741/bgsf/66.2.005; https://doaj.org/article/ff2cdc67eff8404f89f436e109a098cc

Samples from 1265 subfossil pines have been collected from small lakes and peat deposits in the forest-limit zone of northern Fennoscandia in order to study past variations of climate. Many of the subfossils have been dated by dendrochronology and the chronology constructed from the measured ring-width data extends as a continuous master curve from the present back until 165 B.C. and after a short gap until about 7000 years before the present time. This material has greatly increased the number of dated pine megafossils in northern Finland which had previously been restricted only to radiocarbon-dated samples. In addition to the year-by-year information provided by tree-ring width data, the temporal distribution of pine megafossils found in the vicinity of the forest-limit zone also provides information on past climatic changes. The 102 pine subfossils collected from Lake Ailigas, in Utsjoki, form part of the above material. They provide information about past variations in pine growth caused, to a large degree, by changing climate at this one site, but they also give glimpses of the local activities of Prehistoric Man. The data from 90 of these trees have been successfully dated using dendrochronological techniques and the results show that all of them grew during the time period beginning 3000 years before present, and that 79 pines lived during the time span 165 B.C. to A.D. 1952. In several lakes in the forest-limit zone, some subfossil trees are much older than those in Lake Ailigas. The relatively young ages of the subfossils at this site indicates that the lake has been in existence probably only during the past 3000 years, forming when climate turned more humid than in earlier times. The present continuous master curve is about 600 years longer than the earlier published pine chronology for northern Sweden, though this has recently been extended to A.D. 1. In the present study, the life spans of individual dated pines are considered in conjunction with the variability in the measured tree-growth curve. ...