Pine Pollen is a topic of allergy conversation every spring. Pine Pollen is coarse yellow powder, which is scientifically the male microgametophytes (the sexual phase in the life cycle of plants). The powder is windblown from male cones (the small orange granular kind) and then floats into a receptive female cone (the large, hard, drop-to-the-ground kind) and fertilizes the egg located in the center of the female cone. This process grows pine nuts that either are eaten by wildlife, harvested for cooking, or left alone to grow into new pine trees.
There are many different types of pine trees in our area, which provide a long period of pollen shedding. Ponderosa Pines generally flower between April and May but pollen has been collected as early as April 15, and on average May 11, on the west slope of the Sierra Nevada Range. Jeffery Pines typically flower between June and July.
Lodgepole Pines vary by temperature and elevation, but as studied by the U.S. Forest Service, lodgepoles at 6,000 feet elevation in the Sierra have a peak pollen shedding period around June 22. Keeping all this in mind, remember that the rate at which cones develop in the spring is primarily determined by temperature—the warmer the temperature the more rapid the development. Pollen release is also dependent on dry granular pollen cones. In wet weather, pollen release may be delayed for several days and in dry weather, it is hastened.
As seasonal allergies become full blown, most people want to blame yellow pine pollen they see floating in a wind gust, or on the surface of Lake Tahoe, for their misery. The pine trees may not be to blame! Pine pollen is heavy and waxy and drops quickly to the ground. Because it drops so quickly, it usually isn’t a cause of allergies. Those who may be allergic to pine pollen aren’t normally allergic to anything else…just pine pollen.
The main cause of most sniffling, sneezing and congestion around Tahoe in spring may be allergies to many of the other indigenous trees and plants that are producing pollen concurrently with the pines.