Pine trees (Pinaceae sp.) rely on seeds for reproduction. This means that pine trees use sexual reproduction to produce seeds. Part of the propagation process is pollen.
Pine trees produce small, male cones that create the pollen in small, internal chambers. Once the pollen matures, the male cones release the pollen to fertilize the female cones. The cones then die and fall apart after scattering their pollen.
Pine trees release their pollen during the spring. The pollen resembles yellow dust and coats sidewalks, shrubs and cars. The large grains of pollen fall downward and are not blown far by the wind.
According to Maya Jerath, M.D., Ph.D., of the University of North Carolina School of Medicine, pine pollen does not contribute to allergies since it is too large to enter the eyes and nose, which sets off the allergic reaction.
Pine pollen is round with two air bladders resembling ears. This gives the large grains the ability to briefly float in the wind. This feature also makes it easier to identify the pollen grains under a microscope.