Atmospheric deposition of macronutrients by pollen in the boreal forest

Atmospheric deposition of macronutrients by pollen was investigated at three sites in the boreal forest of west-central Manitoba. Tree and rail shrub pollen rain was sampled in late May and June of 1991-1993 using gravity collectors. Jack pine pollen was disproportionately represented in all samples. Total annual pollen deposition ranged between 16-25 kg/ha at the three sites, corresponding to nutrient inputs of 0.34-0.49 kgN/ha, 0.04-0.07 kgP/ha, and 0.11-0.20 kgK/ha. These values are small when compared to estimated boreal forest nutrient uptake rates. However, the combination of highly episodic, early summer deposition and very rapid nutrient turnover suggest that pollen may play an important role in supplying nutrients and promoting decomposition in the forest litter layer.