Open AccessHolocene humidity fluctuations in Sweden inferred from dendrochronology and peat stratigraphy
Author(s) -
GUNNARSON BJÖRN ERIK,
BORGMARK ANDERS,
WASTEGÅRD STEFAN
Publication year - 2003
Publication title -
boreas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 74
eISSN - 1502-3885
pISSN - 0300-9483
DOI - 10.1111/j.1502-3885.2003.tb01089.x
Subject(s) - peat , chronology , tephra , geology , holocene , stratigraphy , scots pine , physical geography , dendrochronology , bog , subfossil , paleontology , pinus <genus> , archaeology , geography , volcano , botany , biology , tectonics
Tree‐ring and peat stratigraphy data were examined back to 5000 BC in order to identify and compare humidity changes in Fennoscandia. The temporal variation in distribution of Scots pine ( Pinus sylvestris L.) was used as a measure of past lake‐level fluctuations in central Sweden. The chronology, which spans 2893 BC–AD 1998 with minor gaps in AD 887–907 and 1633–1650 BC and with additional floating chronologies back to 4868 BC, was cross‐dated and fixed to an absolute timescale using a chronology from Torneträsk, northern Sweden. The peat stratigraphy from the Stömyren peat bog, south‐central Sweden, was transformed into humification indices to evaluate humidity changes during the past 8000 years. The peat chronology is established by four tephra datings and eight 14 C datings. Synchronous periods of drier conditions, interpreted from regeneration and the mortality pattern of pine, tree‐ring chronology and peat humification, were recognized at c. 4900–4800 BC, 2400–2200 BC, 2100–1800 BC, 1500–1100 BC, AD 50–200, AD 400–600 and AD 1350–1500. Possible wetter periods were encountered at 3600–3400 BC, 3200–2900 BC, 2200–2100 BC, 1700–1500 BC, 1100–900 BC, 100 BC‐AD 50, AD 200–400, AD 750–900 and AD 1550–1700. The wet and dry periods revealed by the tree rings and peat stratigraphy data indicate considerable humidity changes in the Holocene.