Amy Stewart

From the creative nonfiction book The Earth Moved: On the Remarkable Achievements of Earthworms

There is a diagram of an apple tree pinned to the wall above my desk - an entire apple tree, meaning that the drawing shows the tree's roots as well as its trunk and branches. The tree itself is only five or six feet tall, but the roots extend an astonishing twelve feet into the soil, and spread much wider than the outer boundary of the tree's canopy. What's fascinating about the drawing is this: the part of the plant that we think of as the apple tree is, in fact, a fairly insignificant part of the full plant. It's just a squat, knobby protrusion at the top of a graceful, expansive system of roots.

Or is the tree at the top of the drawing at all? In some ways, the tree really seems to be at the bottom of its enormous root system. When I turn the picture upside down, so that the roots are on top and the tree is underneath, a much more graceful creature emerges. The limbs run like rivers in every direction. The shape of the root system is perfect, as airy and symmetrical and as any arborist could hope to achieve through years of careful pruning.

When the drawing is turned upside down like this, I am forced to think about the tree's function in a different way. The branches and leaves and fruit are significant, of course: they provide pollen for honeybees, branches for nesting birds, fruit for the gardener, and leaves to carry on the endless respiration of oxygen into the air. But now that I've taken a second look, I see that the roots are the real body of the tree, and I wonder, in a way that perhaps I've never wondered before, what kind of life those roots have underground. How far does the rainwater penetrate? What does the earth look like twelve feet below the surface? If you asked someone what the ocean is like twelve feet below the surface, most people could give you a reasonably accurate description. But how little most of us know about life twelve feet belowground, even in our own backyards.

I realized that I understood very little about the plot of land under my own house. Do I even hold title to this ground twelve feet down? What about twenty, fifty, a hundred feet? The earth's crust extends about fifteen miles down here on the coast where I live. Beyond that, the mantle is thousands of miles thick. Is this little piece of earth mine, all the way down to its hot red center? Surely at some particular depth I lose my claim to it, and it becomes part of a vast unexplored territory owned by no one, like space or the middle of the ocean.

And who lives down there, under my house? When I think of my property as extending not just across to the neighbor's fence, and back to the alleyway, but down a hundred feet or more, I realize that I paid a paltry sum for a kingdom that just happened to have a house sitting on top of it. Millions - no, billions - of organisms inhabit my little piece of land, and it shocks me to realize how little I know of them.

The first inhabitant of the soil to capture my attention was an earthworm. I am a gardener, after all; I can't miss the fact that gardeners and earthworms work in tandem, tilling the soil, feeding the plants. Still, I've always suspected that there was something more to the story of the earthworms. I thought they might have a few surprises in store for me, so I began investigating their habits and lifestyles. Soon I realized that earthworms held the key to most of what was happening belowground.

I keep this picture of the apple tree because it reminds me of something else: a plant's real beauty, its true purpose, might not lie aboveground in the tiny dominion of my garden. There is more to an apple tree than what we can see, much more. To know the land for what it is, to find its heartbeat, to expose its soul, you have to go underground where it lives and breathes.