In "A Walk in the Woods: Rediscovering America on the Appalachian Trail," Bill Bryson reflects on the ancient presence of the Appalachian Mountains. He notes that these mountains have been a constant since the early days of life on Earth, witnessing the transition of basic plant life to more complex organisms as they made their way onto land. The Appalachians, therefore, embody both a geological and a biological history that spans millions of years.

Bryson's observation underscores the significance of the Appalachian region, serving as a backdrop for the evolution of life. As one of the oldest mountain ranges, the Appalachians have a rich history that intertwines with the development of ecosystems on land, marking a pivotal moment in Earth's natural history.