title: Peatland pines as a proxy for water table fluctuations: disentangling tree growth, hydrology and possible human influence.
abstract: Dendrochronological investigations of Scots pine (Pinus sylvestris L.) growing on Männikjärve peatland in central Estonia showed that annual tree growth of peatland pines can be used as a proxy for past variations of water table levels. Reconstruction of past water table levels can help us to better understand the dynamics of various ecological processes in peatlands, e.g. the formation of vegetation patterns or carbon and nitrogen cycling. Männikjärve bog has one of the longest water table records in the boreal zone, continuously monitored since 1956. Common uncertainties encountered while working with peatland trees (e.g. narrow, missing and wedging rings) were in our case exacerbated with difficulties related to the instability of the relationship between tree growth and peatland environment. We hypothesized that the instable relationship was mainly due to a significant change of the limiting factor, i.e. the rise of the water table level due to human activity. To test our hypothesis we had to use several novel methods of tree-ring chronology analysis as well as to test explicitly whether undetected missing rings biased our results. Since the hypothesis that the instable relationship between tree growth and environment was caused by a change in limiting factor could not be rejected, we proceeded to find possible significant changes of past water table levels using structural analysis of the tree-ring chronologies. Our main conclusions were that peatland pines can be proxies to water table levels and that there were several shifting periods of high and low water table levels in the past 200 years.
authors.affiliation: Institute for Botany and Landscape Ecology, University of Greifswald, Soldmannstrasse 15, 17487, Germany. Electronic address: marko.smiljanic@uni-greifswald.de.
authors.forename: Marko
authors.initials: M
authors.lastname: Smiljanić
authors.affiliation: Institute for Botany and Landscape Ecology, University of Greifswald, Soldmannstrasse 15, 17487, Germany.
authors.forename: Jeong-Wook
authors.initials: JW
authors.lastname: Seo
authors.affiliation: Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise St. 46, 51014 Tartu, Estonia.
authors.forename: Alar
authors.initials: A
authors.lastname: Läänelaid
authors.affiliation: Institute for Botany and Landscape Ecology, University of Greifswald, Soldmannstrasse 15, 17487, Germany.
authors.forename: Marieke
authors.initials: M
authors.lastname: van der Maaten-Theunissen
authors.affiliation: Faculty of Forestry, University of Belgrade, Kneza Viseslava 1, 11000 Belgrade, Serbia.
authors.forename: Branko
authors.initials: B
authors.lastname: Stajić
authors.affiliation: Institute for Botany and Landscape Ecology, University of Greifswald, Soldmannstrasse 15, 17487, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wilmking
mesh_terms: D057486:Carbon Cycle; D004784:Environmental Monitoring / Q000379:methods*; D004957:Estonia; D060587:Groundwater / Q000032:analysis; D062070:Hydrology; D058458:Nitrogen Cycle; D041605:Pinus sylvestris / Q000254:growth & development*; D014881:Water Supply / Q000032:analysis; D053833:Wetlands
keywords: Dendrochronology; Hydrology; Missing rings; Peatland; Scots pine; Water table levels