Holocene peatland development and hydrological variability inferred from bog‐pine dendrochronology and peat stratigraphy – a case study from southern Sweden

Abstract

Dendrochronological analysis was applied to subfossil remains of Scots pine (Pinus sylvestris L.) buried in a South Swedish peat deposit. In combination with peat stratigraphy, this approach was explored for its potential to provide information on the local hydrological and depositional history at the site, forming the basis for a regional palaeohydrological analysis. A 726-year ring-width chronology was developed and assigned an absolute age of 7233-6508 cal a BP (5284-4559 BC) through cross-dating with German bog-pine chronologies, whereas two short additional records of older ages were radiocarbon dated. Registration of growth positions of individual trees allowed assessment of the spatial dynamics of the pine population in response to hydrological changes and peatland ontogeny. Annually resolved growth variability patterns in the pine population reveal several establishment and degeneration phases, probably reflecting fluctuations in bog-surface wetness. A major establishment phase at 7200-6900 cal a BP reflects the onset of a period of lowered groundwater level, also indicated by increased peat humification, and a development consistent with regional temperature and lake level reconstructions revealed from other proxies. This study demonstrates that subfossil bog-pine populations may provide annually to decadally resolved reconstructions of local groundwater variability, which are highly relevant in a long-term palaeoclimatic context.

Development of Rich Fen on the SE Baltic Coast, Latvia, during the Last 7500 Years, Using Paleoecological Proxies: Implications for Plant Community Development and Paleoclimatic Research

“…This overall dry period could be linked to the Holocene thermal maximum (HTM), which in NW Europe was characterised by warm and dry conditions (Birks and Seppä 2010;Heikkilä and Seppä 2010). As such a reduced groundwater, lake levels and increase of peat decomposition in peatlands was documented at numerous sites from NW Europe during HTM (Sohar and Kalm 2008;Terasmaa 2011;Berbeco et al 2012;Edvardsson et al 2012;Stivrins et al 2014).…”

Imprisoned in the Cretan mountains: How relict Zelkova abelicea (Ulmaceae) trees cope with Mediterranean climate

“…age related growth trends) and to maximize climatic information. We used the Friedman super smoother method (Friedman, 1984) which is used to model the growth of trees experiencing strong disturbance or competition (Edvardsson et al, 2012;Fang et al, 2010;Leland et al, 2013). The alpha value was left to the default value of 5.…”

Dendrochronologically dated pine stumps document phase-wise bog expansion at a northwest German site between ca. 6700 and ca. 3400 BC

“…This has been found evident on base of abundant upward growing roots late in the tree's life, the drastically narrowing rings near the bark, peat stratigraphical context and the state of conservation at various comparable sites investigated in northwest Germany and southern Sweden (Eckstein et al, 2009(Eckstein et al, , 2010Edvardsson et al, 2012bEdvardsson et al, , 2014Leuschner et al, 2002Leuschner et al, , 2007. Therefore the death of the trees and their conservation under Sphagnum peat dates raised bog expansion, and using in situ stumps adds location to the event.…”