What sex is your tree? And what does it mean for pollen?
DURHAM, N.C. (WTVD) -- We're in that season of yellow when pollen seems to coat just about everything. If you've been outside lately, you've noticed it in the air, on your car, even on your porch furniture. And this time of year, it tends to stick around for a couple of weeks.
Recently, a viewer wrote in with an interesting idea. She asked: "Can we plant fewer male trees? Would more female trees mean less pollen and maybe even more fruit?"
It's a great question, and it made me wonder: do trees actually have male and female parts?
To help answer that, I reached out to Mark Weathington, director of the JC Raulston Arboretum at N.C. State University. He explained that many trees actually have both male and female reproductive parts on the same tree. They are known as Monoecious. However, some species do have separate male and female trees. More on that in a moment.
So, back to all this pollen?
It turns out that the biggest contributors to the yellow storm we see are wind-pollinated trees, such as pines and oaks. These trees release large amounts of lightweight pollen into the air, and it can travel long distances. That's why we can see a yellow haze this time of year. As a matter of fact, the first "yellow" we saw this year was brought to us by southerly winds. The trees in South Carolina spread their pollen up to us before our trees even began producing it.
Different trees with noticeable flowers often rely on pollinators, such as bees. Those trees have pollen that is heavier and stickier, and it doesn't float through the air nearly as much.
When it comes to landscaping, there is some truth to what our viewer mentioned. Species with separate male and female individuals are called Dioecious. Male trees are often planted more frequently in urban areas because they don't produce fruit. That means less mess on sidewalks, driveways, and streets.
But that comes with a tradeoff. Female trees may produce fruit that can be messy, but they also support birds and other wildlife.
In some cases, the choice is pretty clear. Take the Ginkgo biloba tree, for example. Female ginkgos produce fruit with a very strong and nasty smell, and when it falls, it can create a slippery mess. Because of that, landscapers almost always plant male trees instead.
So while it might seem like we could reduce pollen just by changing what we plant, the reality is a bit more complicated. And that means spring in our area will continue to come with a generous coating of yellow.
