Old forests don’t need any fences, coverings for the trees, or birdhouses. They worked out a better survival strategy millions of years ago. If you know where to look, you can discover many of their secrets.

“Have you seen a natural forest?” I asked the couple I was meeting with one morning in the Białowieża Forest in eastern Poland. The Białowieża Forest in eastern Poland is a primeval or “old-growth” forest, meaning that it has developed and grown over centuries with no disturbance, and in that time, created robust and diverse ecosystems. One third of the forests in the world are old-growth forests, including the Redwood National Forest in California.

On their faces I saw consternation. They exchanged a furtive glance, as if they didn’t understand the question, or thought I was nuts. That was no surprise; their professional outfits and decent binoculars showed that they were familiar with being out in nature.

“Well, of course, several times,” the man said.

“We’ve been living by a forest for several years, in central Poland,” the woman added. “It’s natural, it’s been growing for decades since it was planted.”

“Great,” I replied. And off we went.

We walked down a trail through a bright, mixed deciduous forest. Around us grew old lindens, oaks and the occasional spruce. It was the second half of April, my favorite time in the woods. The vegetation was just getting started; first, it had burst out down below and under our feet were growing vast fields of wood anemones, creating a green carpet with a dense covering of white splotches. Over our heads, the crowns of the trees were preparing to open their parasols of leaves. The buds were slowly swelling, but betrayed no outward sign that their brown husks would soon burst as living greenery emerged. Up there, it was the calm before the storm. You