Presenter: This is Close to Nature. Hello and welcome! In our studio today is Robin Black, a Professor of Biology at the University of Iowa and the founder of the Center for Native Peoples and the Environment, who has recently published a book Trees Can Talk. Good morning, Robin!

Robin: Good morning!

Presenter: So, the obvious question is  — can trees really talk? Can they have actual conversations like people?

Robin: That mindset  — comparing trees to people  — is exactly the problem. In our Native American stories trees talk to each other. But science has long decided that this is impossible because plants lack the mechanism that animals and humans use to speak. Since they cannot form words or make sounds, it has been decided that any form of communication is out of the question.

Presenter: Which is not true?

Robin: Not in the least. But it is only recently that scientists have explored the possibility that trees can "speak". One theory is that they communicate via special substances called pheromones that are carried by the wind from one tree to another, full of meaning.

Presenter: This is getting complicated. Could you provide an example?

Robin: Sure. Let’s say one tree is being attacked by insects and is under severe stress. The tree sends out a distress call.

Presenter: No kidding! Like a tree-⁠version of an SOS?

Robin: Something like that. So, it starts producing this specific kind of pheromone that warns the other trees of the insect threat. This gives the other trees enough time to produce defensive chemicals. Wouldn’t you call that communication?

Presenter: That’s incredible! But is it only in an emergency that they talk like this?

Robin: Far from that. Actually, trees talking could explain something that scientists couldn’t understand for years. Do you know what mast fruiting is?

Presenter: Mast  — as in m-⁠a-⁠s-⁠t? Mast fruiting? No, never heard of it!

Robin: Well, unlike fruit trees, which produce fruit every season on a predictable schedule, there are some plants, like nut-⁠trees, that produce fruit at completely unpredictable intervals.

Presenter: Oh! This I have heard and actually experienced! I grew up on a farm, where we had lots of pecan trees. But we could never tell if they would bear nuts the approaching year. And I loved them so much! My father used to tell me that it all depended on how I behaved throughout the year. I still think that was mean. But it worked  — I tried as hard as I could helping him around the farm!

Robin: Honestly, that’s as good a theory as any! Like I said, scientists have puzzled over this for years! It makes no sense  — years of no nuts, and then, out of the blue, every pecan tree across the country bears nuts at the same time. One theory has always been that because nuts are so high in calories, it takes years of storing up sugar for the tree to produce them. But if this were true, each tree would produce nuts on its own schedule, predictable by its condition, age, as well as the habitat and the weather. However, this doesn’t happen. If one tree fruits, they all do. There are no individuals. They act as a collective.

Presenter: How do they do that?

Robin: Again, through a sort of communication, only this time not through the air, but underground.

Presenter: Underground communication? That sounds like a conspiracy theory.

Robin: Not when you hear the explanation. All the trees in the forest are connected by their roots. These root networks redistribute the wealth of sugar from one tree to the other. A kind of Robin Hood  — they take from the rich and give to the poor. So that all the trees are ready to produce nuts at the same time.

Presenter: But why would they do it?

Robin: Through unity they survive. All flourishing is mutual... (fades out).