Absolute pollen productivity and pollen-vegetation relationships in northern Finland

Pollen productivity is one of the most critical parameters for pollen vegetation relationships, and thus for vegetation reconstruction, in either pollen percentages or pollen accumulation rates. We obtain absolute pollen productivity of three major tree types in northern Finland: pine (Pinus sylvestris), spruce (Picea abies) and birch (Betula pubescens ssp. pubescens and B. pubescens ssp. czerepanovii treated as one taxon). Long-term monitoring records of pollen traps from 15 sites (duration: 5-23 years) and tree volume estimates within a 14 km radius of each trap were compared to estimate pollen productivity (grains m(-3) a(-1)) of these trees using a regression method. The slope of the linear relationship between pollen loading and distance-weighted plant abundance represents pollen productivity. Estimated productivities of pollen (x10(8) grains m(-3) a(-1)) for pine, spruce and birch are 128.7 (SE 31.5), 341.9 (SE 81.3) and 411.4 (SE 307.7), respectively. The birch estimate (P>0.05) is not as good as the others and should be used with caution. Pollen productivities of pine, spruce and birch in northern Finland are, in general, comparable to those of congeneric species in other regions of Europe and Japan. Although the year-to-year variations are significant, our volume-based estimates of pollen productivity for pine and spruce will be essential for quantitative reconstruction of vegetation in the region. Copyright (C) 2009 John Wiley & Sons, Ltd.