Even if you weren’t already aware that it’s winter here in the Smokies region, the shimmering white trunks and branches of the sycamore trees along the river valleys would let you know. When the sycamores reveal their bone-like architecture, it’s time to get serious about winter and hope you’ve got enough firewood in place.

This is one tree, however, that won’t do much in the way of providing heat. Its wood is just about impossible to split. Axes literally bounce off of it because the grain of sycamore wood is peculiar; indeed, everything about the structure of the tree is downright strange.

The grain for a given species of tree is determined by the alignment of its xylem cells. These cells form the woody tissue that conducts water for and supports the tree. In woods that are easily split, these cells lie in a more or less parallel plane. That’s why it’s such a pleasure to pile up kindling from, say, tulip poplar.

Some trees are more difficult to split because their cell structures are slightly irregular or even spiraled. But sycamore wood takes the cake. The tree’s cells alternately spiral right-handed one year and left-handed the following year. (Elm is the only other tree I know of that utilizes this growth strategy.) The result is an interlocked arrangement that has been accurately described as “an ax-wielder’s nightmare.”

The early settlers respected this innate toughness. They utilized sycamore wood to make solid wheels for ox carts, wooden washing machines, rolling pins, saddletrees, butcher’s blocks, and shipping crates. Hollow sections made excellent storage bins for grain.

The outer covering of the tree is about as peculiar as its inner grain. Go to the base of most any large sycamore specimen and you’ll find bark plates that have scaled off the upper trunk and limbs. The technical term for this is “exfoliation.” Apparently the outer bark isn’t able to stretch as the tree grows and is cast off. Snakelike, a sycamore sheds its outer skin, exposing ivory-colored inner bark that catches the slanting evening light and gleams like a beacon, signaling winter.

George Ellison is a writer who lives in Bryson City. He wrote the biographical introductions for the reissues of two Appalachian classics: Horace Kephart’s Our Southern Highlanders and James Mooney’s History, Myths, and Sacred Formulas of the Cherokees. Readers can contact him at P.O. Box 1262, Bryson City, N.C. 28713, or at ellisongeorge@cs.com.