Dendroecological investigations on subfossil mire pine woodland in northwest Germany
Dendroökologische Untersuchungen an subfossilen Moor-Kiefernwäldern in Niedersachsen
von Inke Achterberg
Datum der mündl. Prüfung:2017-03-16
Erschienen:2018-02-23
Betreuer:Dr. Hanns Hubert Leuschner
Gutachter:Prof. Dr. Hermann Behling
Gutachter:Prof. Dr. Erwin Bergmeier
Dateien
Name:Achterberg_eDiss.pdf
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Description:Thesis
Zusammenfassung
Englisch
The present work is a dendrochronological investigation of peat-preserved pines (Pinus sylvestris) from northwest German mires (Fed. State of Lower Saxony). The project (DFG funded project LE 1805/2-2) continued the work of the predecessor project (DFG funded project LE 1805/1-2), which had begun the dendrochronological survey of the subfossil pines in northewest Germany. Oak chronologies composed of wood from mires and river deposits had been established earlier. The pines contain environmental indications complementary to those supplied by the oaks. This is one of the reasons to intensely investigate them. The pine remains are a common feature in Northwest-German mires, occurring mostly in extended layers at the fen-bog-transition. Therefore, they provide indications on the phases of enhanced raised bog expansion and formation. The dendrochronological record of peat-preserved pines has already provided major insights towards the temporal history of raised bog formation in northwest Germany. The work presented here continued the work on the pine chronology and the evaluation of the inherent environmental indications: A method for the quantification of a signal of water table rise and mire expansion in the trees was developed and investigated it in context of archaeological finds (wooden mire bridging trackways) from the region which are dated equally precise (manuscript 1). The pine chronology was extended, and the gaps therein reduced considerably. Over all, the number of dendrochronological dated pine trees has been more than doubled (to over 3000 trees), two of four gaps were closed, the total gap length was reduced from 1705 years to 170 years and the cover of the pine chronology was extended by 1771 years, now covering 5369 years and reaching 220 years further into the past. The well-replicated pine chronology has become a considerable dating tool and environmental record (manuscript 2). In a case study, the spatio-temporal development of raised bog was reconstructed. This was uniquely possible using the dendrochronological dating of areal exposed in situ pine remains. In a case study at the mire Totes Moor near Hanover, 210 dated in situ and not-displaced tree remains were used for a spatio-temporal reconstruction of the lateral raised bog expansion across some 500 m (SE-NW) between c. 6600 and 3400 BC (manuscript 3).
Keywords: Dendrochronology; Pinus sylvestris; Peat; Palaeoclimate; Holocene; Bog