Calibrated pollen accumulation rates as a basis for quantitative tree biomass reconstructions

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Calibrated pollen accumulation rates as a basis for quantitative tree biomass reconstructions. / Seppa, Heikki; Alenius, Teija; Muukkonen, Petteri; Giesecke, Thomas; Miller, Paul; Ojala, Antti E. K.

In: The Holocene, Vol. 19, No. 2, 2009, p. 209-220.

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Seppa, Heikki ; Alenius, Teija ; Muukkonen, Petteri ; Giesecke, Thomas ; Miller, Paul ; Ojala, Antti E. K. / Calibrated pollen accumulation rates as a basis for quantitative tree biomass reconstructions. In: The Holocene. 2009 ; Vol. 19, No. 2. pp. 209-220.

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TY - JOUR

T1 - Calibrated pollen accumulation rates as a basis for quantitative tree biomass reconstructions

AU - Seppa, Heikki

AU - Alenius, Teija

AU - Muukkonen, Petteri

AU - Giesecke, Thomas

AU - Miller, Paul

AU - Ojala, Antti E. K.

PY - 2009

Y1 - 2009

N2 - Recent investigations show that the pollen accumulation rate (PAR) of the common tree taxa is directly related to the biomass and, by inference, to the population size of the taxa around the study site. Fossil PAR records preserved in lakes provide therefore a potential proxy for quantitative biomass and population reconstructions. We use the high-resolution PAR records obtained from two accurately dated lake sediment cores in Finland to generate quantitative Holocene biomass records for Pinus, Picea and Betula, the most common tree taxa of the European Boreal forest. PAR values were calibrated to biomass values by comparing the modern PAR values with the modern biomass values and assuming a linear relationship between the past PAR and biomass values. The obtained PAR and biomass values and trends are remarkably coherent between the two records. Pinus has a stable Holocene biomass size and its modern biomass, about 20 t/ha corresponds with the natural Pinus biomass in the study regions. In contrast, Picea immigrated from the East during the mid Holocene, had a maximum biomass, 50-60 t/ha, at 3500-1000 cal. yr BP, and declined strongly during the last 1500-1000 years as a result of increased human activity and related rise of fire frequency. Thus, the modern Picea biomass in the study regions, about 22 t/ha, is only 35-40% of the natural Picea biomass. The results of this pilot study demonstrate the potential of the calibrated PAR data in quantitative biomass and population reconstructions. Such reconstructions can provide fresh insights into the structure of past plant communities and, when combined with records reflecting palaeoclimates, natural disturbances, and human activity, can help to disentangle the long-term importance of different enviromental drivers to changes in plants populations and ecosystems.

AB - Recent investigations show that the pollen accumulation rate (PAR) of the common tree taxa is directly related to the biomass and, by inference, to the population size of the taxa around the study site. Fossil PAR records preserved in lakes provide therefore a potential proxy for quantitative biomass and population reconstructions. We use the high-resolution PAR records obtained from two accurately dated lake sediment cores in Finland to generate quantitative Holocene biomass records for Pinus, Picea and Betula, the most common tree taxa of the European Boreal forest. PAR values were calibrated to biomass values by comparing the modern PAR values with the modern biomass values and assuming a linear relationship between the past PAR and biomass values. The obtained PAR and biomass values and trends are remarkably coherent between the two records. Pinus has a stable Holocene biomass size and its modern biomass, about 20 t/ha corresponds with the natural Pinus biomass in the study regions. In contrast, Picea immigrated from the East during the mid Holocene, had a maximum biomass, 50-60 t/ha, at 3500-1000 cal. yr BP, and declined strongly during the last 1500-1000 years as a result of increased human activity and related rise of fire frequency. Thus, the modern Picea biomass in the study regions, about 22 t/ha, is only 35-40% of the natural Picea biomass. The results of this pilot study demonstrate the potential of the calibrated PAR data in quantitative biomass and population reconstructions. Such reconstructions can provide fresh insights into the structure of past plant communities and, when combined with records reflecting palaeoclimates, natural disturbances, and human activity, can help to disentangle the long-term importance of different enviromental drivers to changes in plants populations and ecosystems.

KW - competitive interactions

KW - climate

KW - population

KW - biomass

KW - Boreal forest

KW - Pollen accumulation rate

KW - Holocene

KW - disturbances

U2 - 10.1177/0959683608100565

DO - 10.1177/0959683608100565

M3 - Article

VL - 19

SP - 209

EP - 220

JO - The Holocene

JF - The Holocene

SN - 0959-6836

IS - 2

ER -