Old growth forests in the eastern U.S were formidable barriers to colonization, places to be subdued and civilized, to fuel industrialization, not preserved. Today, we view old growth forests differently. They give refuge to rare species, support diverse ecological communities, and often provide the conditions necessary for trees to attain their maximum size and age. While visiting Joyce Kilmer Memorial Forest in the Nantahala National Forest, I thought about why these forests remain so important despite the some negative changes they’ve recently undergone.
Prior to European colonization, forests in the eastern U.S. formed a mosaic of complex habitats, owing to natural disturbance regimes and the influences of American Indian nations. An unbroken old growth canopy stretching for the Atlantic Ocean to the Mississippi River is mythical and never existed. Lightning-caused fires, human-caused fires, tornadoes, ice storms, hurricanes, and insects imparted constant change. Some forests were likely disturbed every few decades at minimum, while others grew undisturbed for hundreds of years.
Joyce Kilmer Memorial Forest is one of those places that grew relatively undisturbed. It is a pocket of old growth tucked away in the rugged mountains of western North Carolina. While many impressive trees grow here, the most impressive and largest trees are Liriodendron tulipifera, the tulip tree. Also known as tulip-poplar or yellow-poplar, tulip trees grow fast and tall (the tallest individual tree in the eastern U.S. is currently a tulip tree) and are easy to identify in summer because of their distinctively-shaped leaves.
No live leaves hung from the tulip trees on the overcast, early January day when I visited, but this allowed me to contemplate the trees’ full scale. The tulip trees at Joyce Kilmer are the largest of the species that I’ve ever seen. Many exceed 15 feet in circumference at chest height, approach 150 feet tall, and are several hundred years old.
I was impressed by complex crowns of the largest trees. Most trees in the eastern U.S. today don’t attain such large, complex crowns. They simply aren’t allowed to grow long enough. Many of the crowns were scarred and broken by centuries of battles with wind, ice, and other forces that try to break the tree down.
Since tulip poplars are intolerant of shade, the largest tulip trees at Joyce Kilmer likely sprouted and began to dominate the canopy after a major disturbance, like a fire or tornado, swept through the area several hundred years ago. The now towering tulip trees effectively shade the understory, suppressing the germination and growth of their offspring. Instead of young tulip trees, the understory of the forest was filled with more shade tolerant species like sugar maple and American beech. In a couple of hundred years future visitors may see giant sugar maples growing over the decaying remnants of tulip poplars.
Despite the beauty and stateliness of the trees at Joyce Kilmer, this isn’t forest primeval. No such thing exists in the eastern U.S. Evidence of significant, human-caused changes are easy to find here. Until recently, Joyce Kilmer Memorial Forest contained many large eastern hemlock trees. Now, however, almost every hemlock tree in the grove has been killed by hemlock woolly adelgid, a non-native, invasive insect that basically sucks starch out of the hemlock. I found only a handful of live hemlocks in the grove, and none were particularly large.
Disturbed, young forests are easy to find. Joyce Kilmer Memorial Forest is different. It represents the forests which used to exist and provides examples of the threats forests face today. The tulip trees at Joyce Kilmer are massive, dwarfing almost everything there, especially me. I walked under the trees in wonder even though this place is very changed. I can’t pretend this is the same forest with the same species composition as it was even a hundred years ago. Among other changes, the hemlocks are dead or dying, American chestnuts are functionally extinct, and passenger pigeons no longer darken the skies. Still, I don’t want to demean this place as less special because it’s not what it once was. On the contrary, it is more special because forests like this are so rare.