Trees 'n sneeze - allergy to tree pollen

American Forests, May-June, 1992 by Laurie Gaines

Pollen. That downy dust that travels windswept across our yards and along streets. That wonderful gift of Mother Nature that allows trees to reproduce and survive. That lowdown sticky stuff that coats our cars, flies up our noses, and gets sucked down our throats to cause weeks of misery for over 14 million Americans every year.

What are those little flakes?

Pollen is the male fertilizing agent of flowering trees, grasses, weeds, and other plants and is composed of powdery granules that range in size from microscopic to visible yellow flakes. Pines and oaks produce the largest pollen molecules; this is the pollen that you can actually see. As for the really tiny pollen, though it might seem that the only reason for its microscopic size is so that it can attack us unawares, scientists tell us that its small size and light weight allow it to be carried by the wind.

Each tree has a pollinating season, which begins as early as January in the South and around April in the Northeast. You could conceivably time your travel up the coast to coincide with these reproductive seasons and prolong your exposure--assuming that you are rather masochistically inclined.

Of course, only some unfortunates are allergic to pollen. An allergy is an abnormal response to,substances ordinarily harmless. These substances, when they provoke an allergic reaction, become known as allergens. Technically, when an allergen is absorbed into the body, it stimulates the production of allergic antibodies, which react with the body's cells to produce an inflammation or irritation in particularly sensitive areas--the eyes, nose, lungs, and digestive system. Severe asthma, bronchitis, and skin rashes are all common pollen-caused miseries. In layman's terms, it means you sneeze and sniff for weeks, wallowing in misery.

There are some major offenders in the tree world that allergy sufferers should be aware of. The most common are oak, western red cedar, elms, birch, ash, hickory, poplar, sycamore, maple, cypress, and walnut. Sound like every tree you've ever heard of? Unfortunately for allergy sufferers, all trees produce pollen, and it is possible to be allergic to several species at once. In fact, according to what's known as the "priming effect," if you're allergic to one kind of pollen, chances are you're allergic to several. According to Dr. Gene Chapman, former chairman of the American Academy of Allergy and Immunology's aerobiology committee, the classic allergy cases are people allergic to the alder in Washington state, the birch on the eastern seaboard, and the mountain cedar and juniper in Texas.

Dr. Richard Field, an Albuquerque allergist, says that the allergic reactions to the juniper and the mulberry in the Southwest are brutal. "People find it hard to be lighthearted on the subject," he says. "Some people are so miserable they leave town. Some chop down their trees." It is already against the law in Tucson to plant new mulberry trees, and this law is being seriously considered in Albuquerque as well. But chopping down mulberries and outlawing the planting of new mulberry trees often lead to planting of ash and sycamore, trees that many people are also allergic to. "It is," as Dr. Field puts it, '"a catch-22."

Though we may think we are safer from the offending plants in the cities, allergies in heavily polluted areas are more common and more severe. This is because manmade pollutants, especially nitric oxide, a major component in air pollution, react with pollen to make it more immunogenic (more apt to stimulate the immune system). In addition, the mucus membranes in the eyes, nose, and throat are already raw and irritated by these pollutants. In some urban landscaping, non-native trees are introduced that can provoke previously dormant allergies in some people. The Chinese elm, for example, has brought Albuquerque inhabitants shade--but also the misery of allergies.

In polluted areas, children are twice as apt to have allergic reactions as adults are. Children may have more than pollutants to blame for their allergies. Susceptibility to allergies is hereditary, meaning that people whose families have a history of allergies can expect to have allergic reactions when they come into contact with the offending plants. A person who is allergic to oak pollen may not know of the condition until he comes into contact with an oak tree, which may of course happen at any point in his life, from childhood to adulthood. A southern oak, which has abundant pollen, may be a problem, while the northern species may present no problem.

OK, so now we know all about allergies. But what we really want to know is how to relieve the suffering. There are of course many over-the-counter allergy medicines like antihistamines and decongestants that offer short-term relief, and allergists can provide prescription drugs for more intense reactions. We can also avoid pollen by staying inside, using air conditioning and an air filter. This is especially effective once one knows what one is allergic to, which can be determined by an allergist. Remember, many things besides trees can cause an allergic reaction in people.