Long distance pollen transport cause problems for determining the timing of birch pollen season in Fennoscandia by using phenological observations

Abstract

The male flowering and leaf bud burst of birch take place almost simultaneously, suggesting that the observations of leaf bud burst could be used to determine the timing of birch pollen release. However, long-distance transport of birch pollen before the onset of local flowering may complicate the utilization of phenological observations in pollen forecasting. We compared the timing of leaf bud burst of silver birch with the timing of the stages of birch pollen season during an eight year period (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004) at five sites in Finland. The stages of the birch pollen season were defined using four different thresholds: 1) the first date of the earliest three-day period with airborne birch pollen counts exceeding 10 grains m 23 air; and the dates when the accumulated pollen sum reaches 2) 5%; 3) 50% and 4) 95% of the annual total. Atmospheric modelling was used to determine the source areas for the observed long-distance transported pollen, and the exploitability of phenological observations in pollen forecasting was evaluated. Pair-wise comparisons of means indicate that the timing of leaf bud burst fell closest to the date when the accumulated pollen sum reached 5% of the annual total, and did not differ significantly from it at any site (pv0.05; Student-NewmanKeuls test). It was found that the timing of leaf bud burst of silver birch overlaps with the first half of the main birch pollen season. However, phenological observations alone do not suffice to determine the timing of the main birch pollen season because of long-distance transport of birch pollen.

Development of a regional-scale pollen emission and transport modeling framework for investigating the impact of climate change on allergic airway disease

“…Even though pollen dispersal is normally treated as a local scale transport phenomenon, long distance dispersal (LDD) through mechanically-and thermally-induced updraft turbulent eddies and regional transport is also possible (Kuparinen, 2006). These additional dispersal mechanisms have been confirmed both by observations (Cecchi et al, 2006;Ranta et al, 2006;Skjøth et al, 2007;Mahura et al, 2007) and by modeling using back trajectory analysis (Smith et al, 2008;Markra et al, 2010) and source apportionment (Veriankaitė et al, 2010;Zink et al, 2012). The regional transport of pollen is especially important from a health impact perspective since non-local pollen sources from LDD will change the local pollen load and shift the exposure potential for pollen allergens Zink et al, 2012).…”

Copenhagen – a significant source of birch (Betula) pollen?

“…Research on atmospheric transport of birch pollen is based on the assumption that the most important sources of atmospheric birch pollen in Europe are the forests in Russia, Belarus, and Baltic and Nordic countries Sofiev et al 2006). However, long-range transport of birch pollen is an episodic phenomenon (Hjelmroos 1991(Hjelmroos , 1992Ranta et al 2006;Skjøth et al 2007). It is therefore likely that most of the observed birch pollen in Denmark is related to Danish birch trees.…”

The Influence of Environmental and Atmospheric Variables on Allergenic Pollen

“…Uzun mesafe taşınım ile ilgili çalışmalar özellikle allerjik öneme sahip Betula ve Ambrosia polenleri üzerinde yapılmıştır. Finlandiya'nın birçok şehrinde yürütülen fenolojik modele dayalı Betula polen sezonunun belirlenmesi çalışmasında, 1999 yılında anormal olarak saptanan polen düzeyinin Rusya ve Estonya'dan hava akımları ile taşınan polenlerden kaynaklandığını belirlenmiştir (64). Litvanya'da tespit edilen Betula polenlerinin Letonya, güney İsveç, Damimarka, Belarus, Ukrayna, Rusya, hatta Almanya ve Polonya'dan uzak mesafe taşınımla geldiği saptanmıştır (65).…”