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Biodiversity and Your Allergies

I was on the tennis court with friends who were sneezing and rubbing their noses. Spring and warmer weather means it's allergy season. And most allergy sensitive patients and allergy specialists will tell you it seems to be getting worse every year. Besides a warming climate that heralds spring earlier, botanical sexism, yes sexism! may be a main cause of sneezing and itching eyes.

Trees are either dioecious, meaning each plant is distinctly male or female or monoecious, meaning they have both male and female flowers on each tree. Both monoecious and male dioecious trees produce pollen but the male trees are more to blame for our allergies. And guess what! Most cities have planted only male trees for decades. The lack of female biodiversity is the problem.

In 1949 the USDA Yearbook for Agriculture advised: "When using street plantings, only male trees should be selected to avoid the nuisance from the female seed". So municipalities planted male trees only. To make matters worse, in the 1960s dutch elm disease, a fungal illness spread by the bark beetle wiped out 75% of North America's 77 million elm trees. City planners repopulated with 100 new varieties of maple clones, all male. And because it takes longer for male and female plants to pollinate each other naturally, ornamental plants sold in urban nurseries are mainly male. Botanical sexism!

Without female trees and plants to absorb the excess pollen put out by the males, the pollen clouds float in the air and are potent allergy stimulators. Paul Ries, the director of Oregon State University's College of Forestry says "Anytime we plant an overabundance of one type of tree, whether it is a single species or male trees, there are bound to be problems."

I think this information needs to be known because people don't know much about trees and how important it is to have biodiversity and sex diversity in nature. We don't need to rip out trees but municipalities should be aware of this problems and start planting native female trees of various species. There are dozens of low allergy shady options that could be planted.

Women power is here, and in plants too.


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