Artificial dispersal of foreign pollen into a Scots pine seed orchard

Abstract

Dyed pine pollen was released a total of 24 times from two directions outside a Scots pine seed orchard (distance between rows 7 m, that within rows between grafts 3.5 m). The distribution of pollen within the orchard was measured using 49 samplers of the rotorod type. Meteorological measurements were carried out during the experiments. The amount of pollen released was approximately 1.2^*10¹⁰ grains; the total caught was 39 300 grains. When the releases took place perpendicular to the rows, the pollen plume was wider and shorter than when the release was from a direction parallel with the rows. The airborne pollen concentration decreased inside the orchard at a significantly higher rate when released from a point perpendicular to the grafts than with parallel release. Almost all the pollen was caught within 30 minutes of release. The pollen was resuspended in the air in only small quantities. There are some possibilities of reducing the amount of foreign pollen from at least short distances by modifying the row structure within orchards.