Late Holocene fire history and vegetation dynamics: a pollen and charcoal record from a southern Finnish lake.

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http://urn.fi/URN:NBN:fi:hulib-201801251109
Julkaisun nimi: Late Holocene fire history and vegetation dynamics: a pollen and charcoal record from a southern Finnish lake.
Tekijä: Buchan, Michelle Salkeld
Muu tekijä: Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta
Opinnäytteen taso: pro gradu -tutkielmat
Tiivistelmä: Lake sediments from Valkea–Kotinen, a small lake in the Evo area of southern Finland, were analysed to provide a high–resolution reconstruction of the fire episode and vegetation structure histories of the past ca. 1700 years at the site. Mixing of sediment was a problem in approximately the top half of the core, affecting the accuracy of the chronology and the correct interpretation of pollen and charcoal accumulation. Six local fire episodes were identified using the CharAnalysis program with a mean fire return interval of 312 years. None these episodes could be attributed to human activities with the exception of the episode at ca. 15 cal yr BP which may have been due to the controlled burning of forest for regeneration elsewhere in Evo. The vegetation structure was typical for southern Finland with Picea, Pinus, Alnus, and Betula dominating the site. Signals of human activity such as an increase in Cerealia pollen alongside an increase in microcharcoal from ca. 1000 cal yr BP indicate regional slash and burn activity. An episodic Alnus decline is evident from ca. 1400 cal yr BP with a subsequent recovery at around 1000 cal yr BP. The results show that the local fire regime at Valkea–Kotinen is likely natural and the vegetation structure has been consistent with little anthropogenic influence over the last ca. 1700 years.
URI: URN:NBN:fi:hulib-201801251109
http://hdl.handle.net/10138/231585
Päiväys: 2018-01-25
Oppiaine: Geologia


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