Long distance pollen transport cause problems for determining the timing of birch pollen season in Fennoscandia by using phenological observations
Long distance pollen transport cause problems for determining the timing of birch pollen season in Fennoscandia by using phenological observations
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DOI：
10.1080/00173130600984740
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发表时间：
2006-01-01
期刊：
影响因子：
0.9
通讯作者：
Bondestam, Kristoffer
中科院分区：
文献类型：
--
作者：
Ranta, Hanna;Kubin, Eero;Bondestam, Kristoffer
白桦雄花和叶芽萌发几乎同时发生，叶芽萌发的观察可以用来确定白桦花粉释放的时间。然而，长距离运输的桦树花粉在当地开花的发病前可能会复杂的利用花粉预测的物候观测。我们比较了在芬兰的五个地点在八年期间（1997-2004年）的白桦花粉季节的各个阶段的时间的银桦叶芽爆裂的时间。桦树花粉季节的阶段定义为4个不同的阈值：1）空气传播的桦树花粉数超过10粒/m（-3）空气的最早3天的第一天; 2）花粉累积量达到全年总量的5%、50%和95%的日期。利用大气模拟方法确定了远距离花粉的源区，并评价了物候观测在花粉预报中的可利用性。两两平均值的比较表明，叶芽萌发的时间最接近花粉累积量达到全年总量的5%的日期，并且在任何地点与它没有显著差异（p < 0.05; Student-Newman-Keuls检验）。发现银叶芽萌发的时间与白桦主花粉季节的前半段重叠。然而，由于桦树花粉的长距离运输，单靠物候观测不足以确定桦树花粉主要季节的时间。
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 (1997-2004) 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(-3) 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 (p < 0.05; Student-Newman-Keuls 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.