%0 Research article
%T Past pollen production reconstructed from needle production in Pinus sylvestris at the northern timberline: a tool for evaluating palaeoclimate reconstructions
%A Jalkanen, Risto
%A Hicks, Sheila
%A Aalto, Tarmo
%A Salminen, Hannu
%D 2008
%J Silva Fennica
%V 42
%N 4
%R doi:10.14214/sf.230
%U https://silvafennica.fi/article/230
%X 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 (T<sub>JUL–1</sub>)  correlates statistically significantly with PROD at all five sites and  with PAR in the four northernmost sites. There is also a significant  relationship between T<sub>JUN–1</sub> and PROD at all sites, and T<sub>JUN</sub> 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 T<sub>JUL–1</sub>, PROD and T<sub>JUL–1</sub> 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.