Your Dumbest Friend Explains Tree Sex to You

Happy Arbor Day! As we mainline a heavy dose of touching grass into our veins this weekend, let us also gander at some trees and talk about (tree) sex. 

The other day, as I was sneezing my brains out as a result of my life’s belongings being coated in a thick layer of pollen, I came across a terrifying theory—“botanical sexism.” Great, I thought. Even the trees are sexist now.

Turns out, trees aren’t sexist, just humans (phew!). Botanical sexism is the practice of planting male trees rather than female ones, adopted in urban planning based on the idea that male trees would produce fewer pesky fruits and flowers than those messy, obnoxious female trees. Allergist Tom Ogren theorized that this preference for pollen-producing male trees was to blame for our worsening allergy seasons. However, it’s generally agreed among scientists that our suffocating pollen count is driven by climate change. So you don’t have to punch your neighbor’s willow tree after all! But the more I dug into the theory, the more confused I got. What is a male or female tree? How do trees have sex? And do men ruin everything?

Allow me to explain the complicated, beautiful, and binary-crushing science of tree sex to you. My qualifications are: I have a BFA from an art school, I watched Planet Earth like five years ago, and I once started an unsuccessful compost bin.

Listen up, class! Trees have four primary “sexes,” or rather, ways they have sex. (Don’t tell Republicans). They can be cosexual, monoecious, dioecious, and polygamous. 

Monoecious trees have both male and female flowers on the same plant—think birch, hickory, and fir. Here’s where our sexist urban planners come in: dioecious trees, which are varieties that are strictly male (pollen-producing) or strictly female (fruit and flower-producing). With dioecious trees (holly, willow, and poplar), you need a male nearby to pollinate the female in order to see any fruit or flowers, hence what began the practice of planting only dioecious males. The ginkgo tree, for example, is widely preferred in the male variety due to the rancid smell of the female’s flowers. (Rude as fuck…) 

Most flowering trees are cosexual, meaning they have hermaphrodite or “perfect” flowers: each individual flower contains both the male and female parts (dogwood, red bud, and magnolia, for example). And then there’s the polygamous trees, which have every type of flower on the same plant—male, female, and “perfect.”

There are also tree species that belong to categories of their own, like the avocado tree, a cosexual plant whose flowers can be female in the morning and male in the afternoon(!!!!!), or vice versa. And then there’s the red maple, which can grow in five varying combinations of male, female, and/or perfect flowers. 

So thank you, trees, for giving us fruits, shade, and oxygen, and for teaching us a universally observed fact of life: that sex comes in so many forms.