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Silva Fennica 1926-1997
Acta Forestalia Fennica

Articles containing the keyword 'needle trace method'

Category : Research article

article id 230, category Research article
Risto Jalkanen, Sheila Hicks, Tarmo Aalto, Hannu Salminen. (2008). Past pollen production reconstructed from needle production in Pinus sylvestris at the northern timberline: a tool for evaluating palaeoclimate reconstructions. Silva Fennica vol. 42 no. 4 article id 230.
Keywords: Scots pine; age-depth chronology; annual resolution; needle trace method; NTM; pollen accumulation rate; temperature reconstruction; tree line
Abstract | View details | Full text in PDF | Author Info
Annual needle production (PROD) of Scots pine (Pinus sylvestris L.) and pine pollen accumulation rates (PAR) are compared along a 5-site transect from the Arctic Circle to the northern timberline. PROD is calculated using the Needle Trace Method (NTM). PAR is monitored by two series of pollen traps, located in the centres of mires and within forests, respectively. There is a strong year-to-year agreement in PAR and PROD between the sites for the common 19-year period for which both proxies are available. Mean July temperature of the previous year (TJUL–1) correlates statistically significantly with PROD at all five sites and with PAR in the four northernmost sites. There is also a significant relationship between TJUN–1 and PROD at all sites, and TJUN and PAR at the two northernmost sites. PROD and PAR correlate most strongly in the three near tree line sites, where PROD explains up to 51% of the variation in PAR. On the basis of the calibration between PROD, PAR and TJUL–1, PROD and TJUL–1 are used to reconstruct past PAR. That such a reconstruction is realistic is supported by its agreement with the pollen record for 1982–2000 and with records of male flowering for the period 1956–1973. The use of PROD in reconstructing past PAR can help in interpreting the fossil pollen signal in terms of climate rather than vegetation change and in evaluating the high-resolution dating of peat profiles and calculations of the rate of peat accumulation.
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: (email)
  • Hicks, Institute of Geosciences, P.O. Box 3000, FI-90014 University of Oulu, Finland E-mail:
  • Aalto, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail:
  • Salminen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail:
article id 271, category Research article
Patrick Insinna, Risto Jalkanen, Bernhard Götz. (2007). Climate impact on 100-year foliage chronologies of Scots pine and Ponderosa pine in the northeast lowlands of Brandenburg, Germany. Silva Fennica vol. 41 no. 4 article id 271.
Keywords: Scots pine; needle trace method; climate impact; foliage parameters; Ponderosa pine
Abstract | View details | Full text in PDF | Author Info
Due to differences in the high-frequency signal and mean sensitivity of needle parameters in Scots pine and Ponderosa pine revealed in previous investigations, variance caused by climate factors at a dry site in the northeast lowlands of Brandenburg was investigated. Although water is the general limiting factor for both tree species, there are evident differences in the climate-driven impact on individual needle parameters. Autumn precipitation of the previous year was equally important for Scots pine and Ponderosa pine, but summer precipitation was more significant for the needle parameters of Scots pine. In contrast to precipitation, temperature seems to have a minor impact on needle parameters. Although January temperatures are significant predictors for both species, intercorrelations between needle parameters and summer temperatures were found only for Ponderosa pine. Striking correlation was also found between sun activity and needle production in Ponderosa pine, but not Scots pine, indicating possible adaptation to solar radiation.
  • Insinna, Office for Environmental Protection Liechtenstein, Climate Change Division, P.O. Box 684, FL-9490 Vaduz, Liechtenstein E-mail: (email)
  • Jalkanen, Rovaniemi Research Unit, Finnish Forest Research Institute, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail:
  • Götz, Eberswalde University of Applied Sciences, Department of Forestry, Forest-Botanical Gardens, D-16225 Eberswalde, Germany E-mail:
article id 654, category Research article
Margus Pensa, Risto Jalkanen. (1999). Needle chronologies on Pinus sylvestris in northern Estonia and southern Finland. Silva Fennica vol. 33 no. 3 article id 654.
Keywords: needle age; needle trace method; needle retention; crown thinning; needle loss; shedding
Abstract | View details | Full text in PDF | Author Info
A needle trace method was used to reveal the chronology of needle retention on Scots pine (Pinus sylvestris L.) in southern Finland (two stands) and northern Estonia (two stands). The average annual summer needle retention along the main stem varied from 2.2 to 3.1 in Estonian stands and between 3.4 and 4.2 in Finnish stands during the period 1966–1990. The 23-year-mean needle age was 3.0 and 2.1 years in Finland and Estonia, respectively. In all stands, the mean needle age decreased sharply in 1980s.
  • Pensa, Institute of Ecology, Department of Northeast Estonia, Pargi 15, EE-41537 Jõhvi, Estonia E-mail: (email)
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN-96301 Rovaniemi, Finland E-mail:

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