Pollen grains are a fine dust that plants typically release in spring. They carry the plant's male DNA from the stamen, or male part of the plant, to the pistil, or female part of the plant, in the process known as pollination. Pollination makes fertilization and reproduction possible in plants. Tree pollen is simply the pollen produced by trees. It is a common allergen, though there are only about 100 species of trees that cause reactions in those who suffer from tree pollen allergies. Tree pollen allergies account for about 20% of hay fever symptoms as well.
Trees commonly responsible for hay fever symptoms include birch, redwood, hazel, elm, oak and pine trees. Tree pollen season typically begins early in the spring, since trees normally release their pollen earlier than grass and weeds. In temperate regions of the Northern Hemisphere, tree pollen season typically begins in February or March and continues until about May. In the Southern Hemisphere, the season typically begins in September and ends in February. Some species, such as pine trees, continue to produce pollen into the summer months. The pollen from such trees is usually heavier than the pollen produced by other species, however, so it tends to fall quickly to the ground without eliciting a strong allergic reaction in hay fever sufferers.
Hay fever sufferers typically use a multi-pronged strategy to control their symptoms during allergy season. Over-the-counter and prescription medications, such as xylometazoline, steroids and antihistamines, can manage hay fever symptoms. Preventative measures can help protect hay fever sufferers from excessive exposure to allergens during the tree pollen season as well.
Hay fever sufferers should know what time of the year they're most likely to suffer from allergy symptoms; during this time, they should monitor the pollen count, which is a daily measurement of the number of pollen grains present in one cubic foot of air. Hay fever sufferers should remain indoors on days when the pollen count is high, especially between the hours of 5 A.M. and 10 A.M., when concentrations of pollen in the air tend to be the highest. Hay fever sufferers may be advised to keep doors and windows closed in their homes and cars to keep pollen out. They may also want to dry their clothes in a tumble dryer, since pollen can collect on clothes hung out to dry. It also may be smart to keep in mind that pets and people can contaminate the indoor environment by carrying pollen in on clothes and shoes.