Sometimes, a gust of wind will pick up all the pollen at once. This gives a curious image where a yellowish green shadow of a tree will suddenly drift downwind from the tree that gave rise to it.
At times the pollen in the air will get so thick that you can see waves and waves of it drifting across the country side. Distant mountains will disappear behind clouds of yellow green pollen.
Look carefully at this video and see what I mean: