The Green Illusion

Hi Sanford Smith here with Penn State Extension.

Today the topic of this video is the green illusion.

Green illusion is what we call it.

But sometimes people call it the green lie.

And I'm joined today by Cathryn Pugh.

And she is a forest ecologist and botanist.

And she's going to talk to us a little bit about the green illusion and what that means.

Cat, what's the green illusion?

[Cathryn]: The green illusion is this concept where when you look at a forest and it's lush and green, we falsely equate that to health, where in fact we need to look a little deeper at the plants and get to know what species are growing here and how many different types of those species are found on this landscape.

And once we know a little bit more about those species, we can truly understand how many of those are native and how many are non-native or invasive and what that means for the ecosystem.

[Sanford]: Wow, that's kind of interesting.

So you've mentioned a few things. You said health of the forest.

Can we talk about that in relation to native plants and non-native plants?

[Cathryn]: Sure. Can I define native? [Sanford]: Yeah, sure.

[Cathryn]: Okay, so a native plant is one that has been growing here for thousands of years, and native species have co-evolved with local wildlife, insects, fungi, all of the other living things in this location, this site, this habitat.

And because of that, they are reliant on one another if they recognize these plants as food sources, as nesting sites in a way to complete their life cycle.

And so they need each other to survive. [Sanford]: Right.

[Cathryn]: The native plants and the native other organisms.

[Sanford]: Now, how does that relate to invasive plants or non-native plants?

[Cathryn]: Non-Native plants are those that are not from this site, this part of the world or this habitat.

And so they were brought here or introduced in some way.

And because of that, they have not co-evolved with these other organisms.

So they're not recognized as food sources and habitat uses a non-native plant doesn't inherently mean that it's harmful or bad for the ecosystem, but we do have some non-natives that are considered to be invasive and invasive plants, is one that is non-native and has a suite of other characteristics that make them really successful at growing here.

But in doing that, they kind of take up space and opportunities from our local organisms.

Some organisms are specialist, so they require one plant or a group of plants for their food, or some insects in particular, need certain species to lay their eggs on or feed their larvae.

And if those plants are not in the ecosystem, neither will those insects.

[Sanford]: So the green illusion is that when people see the forest and they think, oh, it's healthy, it's beautiful, but in fact it's not really that it has a bunch of non-native things that are not doing the good services that the native plants directly.

Okay. So it's yeah, it's really a misperception, isn't it?

When they see the forest. [Cathryn]: Yeah.

So what's happening is with these invasive plants, they are really good at reproducing.

So they produce lots of seeds they can grow in to newly disturbed areas first.

So they're taking up space that would otherwise be there for native plants to grow.

And on top of that they have this interesting phenomenon called extended leaf phenology, meaning that these plants that turn phenology is like the cycle of plants characteristics.

And so extended leaf analogy means they have leaves that come out in the spring, a week or two earlier than our natives, and then hold on to those leaves a week or two longer.

[Sanford]: So they've got a competitive advantage, don't they?

They get in food a little earlier and they're hanging in there a little.

When do people experience this green illusion phenomenon?

[Cathryn]: It happens when you're looking at the forest with an untrained eye.

So essentially to overcome or or to not experience the green illusion, you have to get to know the plants in your forest.

And there are a lot of ways that you can do that.

Some are talking to somebody like your service forester through DCNR or coming to an Extension event.

Lots of plant identification walks and workshops happen.

[Sanford]: Cat. I want to thank you very much for joining me today.

This has been fun.

Invasive plants and native plants are important for people to know about.

And this green illusion of seeing the ecosystem that you're in, like a forest or even a field, and thinking that it looks healthy is something that people need to be aware of.

Thank you very much for listening, and thank you for joining me.

[Cathryn]: Thanks for having me.