For decades, Ogren has researched the allergy-potential of all the commonly used horticultural plants. His studies have confirmed male trees are being favored over female trees which is making allergies worse – a process otherwise known as botanical sexism.

“They do that because the female trees will drop seed pods, or seeds, or flowers or maybe a fruit of some sort on the sidewalks, and they want to have clean, tidy sidewalks. That’s what’s driving this whole thing.”

On the other hand, males produce the pollen to fertilize the female’s seeds. As more male trees are planted, pollen counts increase, and as a result, more and more people are experiencing severe allergies. Dr. Clifford Bassett, the medical director of Allergy and Asthma Care of New York, says Ogren’s study is exciting because it can help people to know what to plant to help their allergies.

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