JEFF: There are some general definitions. But a really good working definition that separates out the different plants into categories by how much they really do to our native ecosystems that you're talking about – in my opinion we really don't have that right now.
AMY: So it's really just a matter of, "I see some buddleia in the ravine down the street from my house, so buddleia must be invasive?” Whether it’s actually threatened another plant or not?
JEFF: Right. Exactly. And here it’s buckthorn. Buckthorn seems to be taking over at the edges of forests, and I see it too. Is it an invasive that needs to be controlled at any cost, or is it just a more vigorous plant? Often that question is decided more by politics than science.
AMY: There was one more really interesting point in your book that I wanted to bring up. You made the point that Europe is a completely disrupted, non-native ecosystem. Humans have been there for thousands of years, chopping down trees and bringing in other plants. I thought about that when I was in France this fall. There really aren't any native, undisturbed areas like we have here. I mean, the place was deforested in Roman times. I hear all this talk about advanced forest management practices in Europe that allow much more logging than we allow here—it’s an argument used by the timber industry to justify more clear-cutting—but I drove through a French national forest. It was a tree farm! Literally, trees planted in straight rows and cut on 100-acre rotations. I realized that they just don’t have the kind of ecology we have here.
JEFF: Yes, and when I made that statement in the book I was really thinking about England in particular. They have been bringing plants in since the 1500s. They don’t even know whether the pear is native to the region.
AMY: And yet, as you point out in the book, it continues to be an ecosystem that functions in some way. I mean, England is obviously capable of supporting life — plant life, human life, animal life.
JEFF: But what they have is completely different from what they would have had if humans had never entered the scene. Nature has a way of finding its own balance. New plants change the balance, but that doesn’t mean that the balance ceases to exist.
It's called How the Government got in Your Backyard, and it's available at bookstores everywhere. Check it out.