Pine trees are long-lived, coniferous evergreen trees. They fall into the category of gymnosperms, since the seeds of the trees are not fully enclosed and thereby shielded from the environment. When dealing with pine pollen, you should look to the smallish pine cones, also known as strobili, that are located on the upper and lower branches of the pines. It is from the male cones that copious amounts of pollen eventually take to the air each year during spring.
Yellow pine pollen is the product of a tree’s male strobili. Female strobili, which are considerably bigger than the male cones, grow toward the top of the pine, whereas their male counterparts grow on the lower branches. During a two- to three-week window--usually in early to mid-April--the male strobili release their pollen into the air.
Pine pollen does not rely on bees or hummingbirds for transport but instead counts on the wind to traverse longer distances. Its exterior structure features two wing-shaped attachments that enhance the pollen’s aerodynamic qualities for further geographic spread. This explains the far-reaching spread of pine trees across the United States.
Coniferous pine trees produce copious amounts of pollen. The sheer quantity of these grains translates into the highly visible carpeting of walkways, lakes and streets with a layer of gold-colored grains. Residents who have pine trees on their properties will notice that a lot of yellow dust accumulates on furniture and floors during the spring. This, too, is likely to contain pine pollen that entered the home through open windows, small cracks or was tracked in.
Pine pollen that is carried by the wind ideally lands on the female strobili of other pine trees. After a pollen grain comes to rest on a female strobilus, it germinates and grows a pollen tube through which the male gametophyte travels into the female ovule. As sperm and egg fuse, they form a zygote. After further cell division, an embryo forms within the ovule. A hard seed coat develops from the ovule’s outer layer.
It is a common misconception that the yellow blanket of pine pollen is a major contributor to the seasonal allergies that affect those suffering from pollen allergies in particular. In fact, pine pollen is not nearly as allergenic as other types of pollens that may be lighter and do not actually fall to the ground but remain airborne for prolonged periods of time.