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Mon May 27, 2019, 08:37 PM

'Botanical Sexism' Could Be Behind Your Seasonal Allergies

https://www.atlasobscura.com/articles/seasonal-allergies-blame-male-trees

More diversity in city trees would probably be a good thing.



ONE DAY THIS PAST APRIL, the residents of Durham, North Carolina, saw the sky turn a peculiar but familiar shade of chartreuse. Enormous clouds of a fine, yellow-green powder engulfed the city. It looked, and felt, like the end of the world. “Your car was suddenly yellow, the sidewalk was yellow, the roof of your house was yellow,” says Kevin Lilley, assistant director of the city’s landscape services. Residents, quite fittingly, called it a “pollenpocalypse.”

Male trees are one of the most significant reasons why allergies have gotten so bad for citydwellers in recent decades. They’re indiscriminate, spewing their gametes in every direction. They can’t help it—it’s what evolution built them for. This is fine in the wild, where female trees trap pollen to fertilize their seeds. But urban forestry is dominated by male trees, so cities are coated in their pollen. Tom Ogren, horticulturalist and author of Allergy-Free Gardening: The Revolutionary Guide to Healthy Landscaping, was the first to link exacerbated allergies with urban planting policy, which he calls “botanical sexism.”

In trees, sex exists beyond the binary of female and male. Some, such as cedar, mulberry, and ash trees, are dioecious, meaning each plant is distinctly female or male. Others, such as oak, pine, and fig trees are monoecious, meaning they have male and female flowers on the same plant. It’s easy to identify female trees or parts—they’re the ones with seeds. And yet more, such as hazelnut and apple trees, produce “perfect” flowers that contain male and female parts within a single blossom. But while both monoecious and male dioecious trees produce pollen, Ogren claims the latter are primarily to blame for our sneezes and watery eyes.



Ogren has been talking about this botanical misogyny for over 30 years. After buying a house in San Luis Obispo with his wife, who suffers from allergies and asthma, Ogren wanted to get rid of anything on his property that might trigger an attack. He began examining the neighborhood, plant by plant, when he noticed something unusual: All the trees were male.

At first, he thought this pattern may just have been a strange quirk of one city. But when he studied frequently landscaped plants in other cities, he noticed the same thing: males, all the way down. “Right away I started realizing there was something weird going on,” he says. While tracking down the origin of this trend, Ogren stumbled upon perhaps the first trace of sexism in urban landscaping in a 1949 USDA Yearbook of Agriculture. The book advised: “When used for street plantings, only male trees should be selected, to avoid the nuisance from the seed.”


Male trees release more pollen when there are not enough female trees around. They absorb pollution from the air and release it into their pollen. And like most problems, climate change makes the pollen clouds worse.

I'd rather have female trees with seeds. I'll volunteer to sweep the seeds in my neighborhood if that's such a big problem.

Another article on this:

Sniffling and sneezing? Too many male trees are (partly) to blame.
https://ggwash.org/view/62585/sniffling-and-sneezing-too-many-male-trees-are-partly-to-blame

5 replies, 1154 views

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Reply 'Botanical Sexism' Could Be Behind Your Seasonal Allergies (Original post)
IronLionZion May 2019 OP
2naSalit May 2019 #1
IronLionZion May 2019 #2
2naSalit May 2019 #3
IronLionZion May 2019 #4
2naSalit May 2019 #5

Response to IronLionZion (Original post)

Mon May 27, 2019, 10:42 PM

1. Huh...

I didn't know that male trees dominated the landscaping industry but I'm not surprised. In the mountains we see that every spring but we still have forests.

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Response to 2naSalit (Reply #1)

Mon May 27, 2019, 10:57 PM

2. Forests will be more balanced with male and female

cities have been planned to have more male trees.

The greater washington article describes the issue well, in that many types of trees have both male and female parts, and there are female trees that have been sterilized. For allergies in DC, they claim the most likely culprit are red maple trees, poplars, and gingkos.

When there is balance, the pollen is more likely to get to female trees faster. When it's unbalanced, there is more pollen released and flying around.

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Response to IronLionZion (Reply #2)

Mon May 27, 2019, 11:08 PM

3. I undersrand the rest...

I just didn't see it as a thing because i don't live in cities. In the area I live, whole mountainsides can be shrouded for hours on a windy day, also valleys can be yellowy green for about a week.

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Response to 2naSalit (Reply #3)

Mon May 27, 2019, 11:38 PM

4. Sigh, I wish it were just a week

It's been the last several months here in DC.

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Response to IronLionZion (Reply #4)

Mon May 27, 2019, 11:48 PM

5. Oh dear!

I can see how that would be a problem! The pollen spills don't bother me much, my eyes stay red but I don't get hay fever. It can go on longer but the bulk pollen releases are in the forests and they all seem to be on the same time schedule. I have some rally cool pictures of pollen puddles similar to those in the article.

I feel for anyone who has allergies to all these pollen types.

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