by Pieter van Loon, VLT forester —
I was recently reminded that ash trees are dioecious (pronounced die-EESH-iss). That is just a fancy way of saying there are male ash trees and female ash trees. For most of the year you can’t tell them apart, but right now it is easy. Just look up. If you see seeds, it’s a female. No seeds, male. It strikes me that now is a particularly good time to know this.
Emerald ash borer was found in VT this winter. We heard the same message you did: “Don’t panic. There is time to plan.” We are trying to figure out what to do with ash on VLT land. Some ash will be left behind in hopes that they will regenerate, but, since they are dioecious, we can’t just leave one tree and expect it to work out.
Turns out, the recommended ratio is 6-12 male trees left for every female. This is to be sure there is enough pollen to blow around and fertilize the female flowers. If your next timber sale is more than a year away and you want to retain some ash trees with the goal of getting some regeneration, you might want to go out now and mark the males and females.
The picture below shows a stand of ash on conserved land in Tinmouth being blown around by a brisk south wind. There are lots of red and yellowish clumps of seeds on the ash in the center of the photo. Almost all the rest have no seeds. The center trees are female and they are surrounded by males. Let’s hope some of those thousands of seeds will germinate into ash trees that will either survive EAB or live long enough for us to figure out a way to control it.
About Pieter’s Lens: Not only does Vermont Land Trust forester Pieter van Loon know his trees, but he is also a great photographer and observer of wildlife. We asked Pieter to share what he sees in the field as he visits land conserved with VLT. Take a walk in the woods with Pieter by following #PietersLens on our social sites