(pensive music) - Soils are deep and complex places, like when I walk around on the soil, I like to think of it like I'm walking on the surface of an ocean of land and that that ocean of land stretches down deep, deep underground and is full of life.

(waves rumbling) Coniferous forest we see here in Oregon, those have particular types of fungal relationship and bacterial relationship and they in turn shape the soil that they grow in and the fungi shape the conditions for the plant.

So it's a kind of feedback system where you have chemical weather systems, you have microbial populations, you have plant activity and all are conditioned by the other.

And so yeah, what we see is just the visible part of a much vaster and more complex system.

My name's Merlin Sheldrake, I'm a biologist and a writer and I think a lot about fungi and in particular, the fungi that form relationships with plants.

It really helps, I think, see things a little bit more from their perspective.

But a lot of time, you just got to let your eyes get used to the forest and you see one or two and you start to see more, but it helps to come down, I find, also just to enjoy them.

Plants tend to produce their own food by eating sunlight and carbon dioxide to produce sugars and fats.

Animals tend to go around in the world and find food and put it inside their bodies.

But fungi do things differently, they put their bodies inside their food and they do this by growing, branching, fusing networks of tubular cells called mycelial networks.

From a fungus's point of view, it's like, well, I've got all these plant partners, it's in my interest as a fungus to make sure that I have these multiple plant partners, in case one of them dies, in case one of them gets eaten, one of them is squashed by a falling tree.

They have to rise to the challenge of living.

They have to explore a changing environment.

They have to adapt to these changes in their environment.

They have to make decisions in their way, between different causes of action.

And so fungi have evolved all sorts of ways to do that, to solve problems.

We forget how hard it is to digest wood.

Lignin is one of the parts of wood and lignin is really hard to digest, 'cause it's in irregular structure and so normal enzymes just can't handle it.

Some fungi you have the certain types of enzyme, which can break down the lignin in wood and unlocks all the carbon in this wood and allows it to become available for other organisms.

So they play really vital roles, helping nutrients to journey through their earthly cycles.

I love thinking about the life of the tree after it's fallen and you have this tree when it's alive, and then you have this body of the tree when it's fallen, it becomes the site of, like a planet, for so many different organisms, continuing their lives and in some ways it's more living than it ever was.

It's a world of communication outside, we live in a communicating world.

Some of that communication is visible and apparent to us and most of it passes under our feet, over our heads.

(pensive music continues) (participants talking indistinctly) (Merlin laughing)