Shagbark hickory trees are tall, straight columns reaching into the canopy.
Shagbark hickory trees can live for three hundred and fifty years. That means that there could be shagbark hickory trees in the Sourlands that started their life at about the same time that European settlers arrived. These trees would have been a hundred years old when George Washington became president. They would have been two hundred years old when the Wright Brothers made the first airplane flight.
Shagbark trees can grow to more than a hundred feet tall, but they are quite thin for a tree of that height. There are reports of hollow old sycamores that became big enough around to be used as shelters for livestock and even for people, but the trunks of fully mature shagbarks are only about three feet in diameter. They may not have girth, but two of their features give them presence. First, the bark; while most trees have furrows or plates in a pattern as ordered as a Haydn symphony, shagbark trees have long strips of loose bark, usually running up and down the tree. Sometimes, however, squirrels, woodpeckers, or strong winds cause the strips to become twisted sideways. The shaggy and irregular bark creates a black-on-black pattern; the outer layer of bark is lighter, really charcoal grey, while the gaps between the strips and the shadows they cast are black and blacker.
The irregular appearance of the bark is in stark contrast to the hard, straight-grained wood. Their slow growth contributes to the hardness of shagbark hickory wood. From the outside, the tree may look like it is coming apart, but inside the shagbark hickory is solid and sturdy.
The second feature is only visible in the spring. They have very large leaf buds which, when they open in spring, display a pattern of unfolding leaves that is as bizarre and exotic as a tropical flower. The rolled leaves are yellow, even orange and sometimes mauve, and when they emerge they point in different directions, displaying their release after being tightly confined inside a bud for six months. Soon this display turns into clusters of small, prominently veined yellow leaves that glow in the spring sun for a short time before they gain chlorophyll and become a conventional shade of green.
The shagbark hickory leaf bud opening in spring is an exotic-looking display.
When I see a shagbark hickory in the forest I see it as an integrated part of all that is before me. Together, with the other trees, it is shading the ground, preserving soil moisture and determining where understory trees and shrubs can find enough light to grow beneath them. Together, with the other canopy trees, the understory trees, and the shrubs, they create a pattern of shadow and light that determines where the ferns, grasses, sedges, and other herbaceous woodland plants will grow. Together, with all of the leafy plants, they are changing the atmosphere around them by absorbing carbon dioxide and exhaling oxygen and water vapor. Together, all the plants in a forest drop leaves, twigs, and other parts that eventually enrich the organic content of the soil. Together, they are all connected through mycorrhizal fungi, drawing water and minerals from the soil and using the fungal network to share these resources amongst themselves.
The forest is a whole, not a collection of individual plants, but I also see each tree in the forest as the center of its own universe. Included in a tree’s universe are the animals that are attracted to it for food and safety and the animals that are attracted by those animals. The universe of a shagbark hickory tree has some qualities that are unique. Beneath those long, loose bark strips insects, spiders, and even, on occasion, a roosting bat find safety. More than two hundred species of moths and butterflies lay their eggs on shagbark hickories so that the caterpillars that hatch from those eggs in spring can eat the shagbark leaves and flowers. Neotropical songbirds—warblers, orioles, tanagers, and grosbeaks in particular—are drawn to these caterpillars as a source of protein for themselves and their new families. The birds that rely on these insects often build nests or make cavities in shagbarks. Hawks, especially sharp-shinned and coopers, are attracted to the birds that are attracted to the caterpillars.
Shagbark hickory trees are unreliable bearers of nuts; some years there is an abundance, while most years the nuts seem to be eaten by wildlife as soon as they fall from the trees. This is the pattern of oaks and all trees that bear nuts; the maximum population of the nut and acorn-eating wildlife is determined by the low-productivity years so when there is a year of high productivity the extra nuts and acorns bring seeds to replenish the forest with new seedlings.
Shagbark hickory nuts are sweet and are food for a wide range of birds and mammals. Wild turkeys, woodpeckers—especially red-bellied woodpeckers—blue jays, and even wood ducks eat the nuts. (Turkeys and ducks swallow the nuts whole and their digestive systems crack them open; the shell is passed with their waste material.) Black bears, chipmunks, red, grey, and flying squirrels, raccoons, rabbits, and white-footed mice also eat shagbark hickory nuts. Foxes eat the nuts and try to eat the small mammals that are eating the nuts. Native Americans of the eastern forest and European colonists relied on shagbark nuts as part of their diet. Few people eat them today because it is difficult to extract the meat from the shell, but as I was writing this essay I realized that I had not eaten a shagbark nut for several years. It was mid-September, so I went out and gathered some nuts, came home, got a hammer and broke them open. It was really hard to get more than a fragment of nutmeat at a time but they were delicious.