Opening my eyes and crouching with one knee in the damp earth, I place the flat of my palm on the ground, feeling the tangled web of corded roots. It’s just a fraction of what’s down there. The merest glimpse of the forest’s dynamic internal system. Like the few visible veins on the back of your hand. “A tree is a passage between earth and sky,” as Richard Powers has written. But much of it is well hidden. Hard to believe that, even now, moisture and nutrients from the soil are silently traveling along not so very far beneath my fingers, inching up toward the foliage high above. Making their own climb through the forest as we make ours. That the leaves and needles are cooking them up, concocting the sugars and sap they need to survive. That much of the oxygen we’re breathing is simply a by-product—an airy sizzle in the pan.