If you live in the city and have allergies, you might be interested to learn that one reason you're sneezing so much is "tree sexism". No, I hadn't heard of this either.
In a short thread that went viral on Monday, writer and Twitter user Jessica Price highlighted a problem of "botanical sexism" that's been going on for years in the US.
Male trees produce and release pollen into the air in order to fertilize female trees. Female trees do not produce pollen, and will trap large amounts of it from the air, using it to make seeds.
When male trees release pollen, a lot of the time it gets inhaled by you, where (if you are one of the 25 million Americans with hayfever) your immune system believes it to be an invader and overreacts like Trump to a Saturday Night Live skit. Antibodies released by your immune system attach to the allergens and then trigger the release of the inflammatory chemical histamine, which is what causes your eyes to itch and your nose to run horribly.
Yet cities around the US have been planting mainly male trees for years, producing an excess of pollen which there are too few female trees to catch out of the air. Why? It would appear at least part of the answer is because cities believe male trees are less "messy".
Horticulturalist and author Tom Ogren – who first uncovered the strange problem in urban planting policy around 30 years ago – bought a house in San Luis Obispo, and began having allergic reactions. He started examining neighborhood plants, Atlas Obscura reports, and noticed that all the trees were male.
He believed this must have been a strange oddity of San Luis Obispo before he started looking at other cities and noticed the same thing wherever he went.
“Right away I started realizing there was something weird going on,” he told Atlas Obscura.
Investigating, he found that the 1949 USDA Yearbook of Agriculture advised: “When used for street plantings, only male trees should be selected, to avoid the nuisance from the seed.”
The US Department of Agriculture advised that female trees were too messy – shedding seeds, fruits, and pods – and believed male trees to be tidier, shedding only a pesky allergen all over America's cities.
During the 60s and 70s, Dutch elm disease struck America, causing millions of trees to die and streets all over the country to become treeless. When replanting, it appears cities chose to plant male trees to replace those that were lost. Cut to years later when these trees are mature, and they're producing massive amounts of pollen. Even more as they grow and grow.
Ironically, if authorities had planted only female trees, we'd have none of the mess or the allergens.