In the present
data, the influence of mean wind conditions is especially clear
for 17 July (Fig. 10a). At 0700 EDT, the RH was below 100% and
dropped fast starting at 0800 EDT. However, the first pollen
grains were captured only between 0900 and 1000 EDT, during
which VPD values increased from 0.84 to 1.08 kPa. In this case,
there was no wind during early morning hours and the wind
started to pick up only around 0830 EDT. Thus, although
conditions for anther desiccation were fulfilled, i.e. low RH
(high VPD), winds were not sufficiently strong to transport
pollen grains upwards.