I sat at the table as a student while a fellow educator modeled a lesson. We first made observations of different tree leaves. Words poured out. Smooth, zig-zag, oval, pointed, thin, fuzzy, bumpy, green, symmetrical, not symmetrical, dark green, even darker green.

She then asked, “Why are there so many different shaped leaves?”

Conversation stopped. I’ve never thought about that question before. Why the diversity? There are over 60,000 species of trees worldwide not to mention the leaves of all other green plants. If one were to compare all the leaves on one individual tree, none would be exactly alike. But each leaf is designed to do the same job. They collect sunlight, create sugar, and release excess water and oxygen. Over the millions of years that green plants have been evolving, the leaves have been the food factory of the plant. Each leaf developed to work in the place it lived. Could it be that the ones that work are still around and the ones that didn’t work aren’t?

Hemlock Cones release their seeds in fall and early winter.

I think about this idea sitting in the woods, looking up at the deep green canopy. Various leaf shapes overlap, layer upon layer, some catching sun, others shaded. Small patches of blue make it through, the leaf shapes silhouetted against the sky. Petite but tough oval needles of Eastern Hemlock and papery, serrated ovals of Yellow Birch dominate the canopy. Occasionally, the softer color and texture of White Pine and Sugar Maple break the pattern.

A creek among the forest.

This is my favorite kind of forest. In the cool, damp ravines of our eastern region, this forest thrives. In the loamy, rocky soils these trees grow where many others cannot. Along with the creek, gurgling as it tumbles over and under moss covered rocks, they create an atmosphere of comfort and peace.

This place appears calm and quite. But at this very moment, things are being broken. In the canopy, sunlight is breaking apart the bonds of water and carbon dioxide and rearranging them into sugar and oxygen. Green plants are the only thing that can take these non-living materials and build life. From the leaves, this sugar is transported throughout the tree to make more leaves, buds and flowers, larger branches, wider trunk and bigger roots. What a marvelous thought — to feed oneself off the very elements of the earth. To be the foundation of the living food chain upon which all other life depends.

But in this forest, bigger things are breaking too. A tree that has fallen. Maybe due to disease, lack of resources, or just old age. It decomposes on the forest floor. Hundreds of years of building is now being torn apart.

Looking closer at a decomposing tree, I see a carpet of moss, tunnels from insects where they have traveled, and the dusty remains of their meals. Each movement of root, foot, and mouth knock off a bit more of the tree.

I touch it and feel the work of things I cannot completely see. Fungus and bacteria have softened the wood to a spongy consistency, perfect for holding on to rain long after the forest floor has dried. While the round, elongated shape of tree trunk is still recognizable, it appears less like a tree and more like the soil it will one day become. It feels as if it crossed a line and is no longer a tree. But what do I call it? Old tree or new soil? It makes we wonder, in the process of change, when do we stop being what we once were and claim the title of our new being? Or are we always what we’ve been and what we will be?

I look at the seedlings on this fallen tree. Perhaps a year old, maybe two. Their first real leaves a micro version of what could be. There are at least twenty in a square foot. Just to get to this point is a miracle. Every year, seeds rain on the ground. Yellow Birch can produce over a million seeds in one year. They hope for a place such as this. Where there is just enough soil, water and light. Where the temperature is just right. Then they put down roots, literally, in their one and only chance to become what they came from.

Hemlock and birch seeds often germinate on decomposing logs because they are warmer and wetter than the forest floor.

But who is to win? When the old hemlock, whose ample branches now shade the seedlings, finally falls, who will capitalize on the light to rise up and take its place? It will be the one that doesn’t get too wet or too dry, fall to a fungus, fire, feeding insect, hungry deer or other unknown calamity.

In the deep shade under the hemlocks, this forest feels ancient. As if the trees and the rocks have always been here. But of course they have not. Yellow Birch may hold its place in the forest canopy for over to 200 years and Eastern Hemlock double that. But there was a time when these trees were not here. A time when these towering giants landed as a seed in this very place and put down a single root. The ones whose leaves I stare up at now are the ones that survived. And these are the ones that will nurture those yet to come.

Trees feed themselves in the most remarkable way. And when their life comes to the end, they feed the new forest. The forest is constantly renewing itself. And when you go into the forest it can feed and renew you too.

Katie Finch is a naturalist at Audubon.

Audubon Community Nature Center builds and nurtures connections between people and nature. ACNC is located just east of Route 62 between Warren and Jamestown. The trails are open from dawn to dusk as is Liberty, the Bald Eagle. The Nature Center is open from 10 a.m. until 4:30 p.m. daily except Sunday when it opens at 1 p.m. More information can be found online at auduboncnc.org or by calling (716) 569-2345.