I really kind of like weird wood. You know, trees with character: twisted trunks, branches with 90 degree elbows, two trees of different species growing intertwined, completely hollow trunks sprouting live branches, and other freakish abnormalities. Winter walks in a leafless forest, especially with highlights of snow outlining branches, allow these interesting anomalies to pop out of the scenery.
Each one must have a story, and I find myself guessing at the cause when confronted by such a freak of nature. Was this tree, as a sapling, clobbered by a nearby fallen giant, causing the main stem to bend then grow straight up again after the trauma? Did that tree sprout on top of a rotting, fallen log, causing its roots to grow around the now-absent log so that today it looks like it’s standing on tip toes? I don’t perceive these trees as funny-looking. Rather, I’m awed by their strength to survive obstacles and hardship.
Sometimes there’s a really big, misshapen blemish, a giant tumor, covered by bark. These huge tree swellings are known as burls (in Britain they’re called burs or burrs). What causes them? One can guess, but can’t truly say why with certainty in most cases. Like galls on smaller, soft-tissued plants, they can be caused by insects and other arthropods, fungi, bacteria, physical wounds, and environmental stress.
Occurring on trunks and occasionally on larger branches, burls can be found on most tree species and commonly on ash, birch, cherry, elm, maple, oak, sycamore, spruce and walnut in northeast Ohio. Sometimes they protrude from one side and other times they encircle an entire trunk. They can be found near the base, at eye level, and sometimes 30 feet up or more. There may be a single growth or a profusion of tumors on one tree. They might be as big as your head, or four feet in diameter, sometimes more. Burls will grow on skinny 10-year-old specimens or giants of great girth.
While they’re odd and sometimes even painful-looking, burls don’t measurably affect the continuing growth of a tree. Sometimes adventitious buds will even sprout from them.
The wood grain inside of a burl is something special. It’s twisted and gnarly and multidirectional. It has been prized for centuries by craftsmen who use thin sheets of it as decorative veneer on cabinetry and in detailed inlay work. More recently, wood turners fashion beautiful bowls from burls using a lathe. Some will even make table tops from thick slabs of large burls. They can make a beautiful, highly decorative piece without effort of carving or inlay. However, the unexpected twists of the grain can also cause unexpected splitting, or reveal rot and knots. Burls can lower the timber value of a tree, but in the right hands and in the right market, they can actually increase its total monetary value.
In fact, burl poaching has become a problem in the giant redwood forests of the west coast. Redwoods can be prolific burl producers, with large knobs near the base. Hacking off huge swaths of wood along with the growing cambium layer and protective bark is like downing an elephant to hack off tusks. It dooms the individual tree and further, because the redwood burls often contain unsprouted bud tissue, it can eliminate growth of potential future trees. When purchasing any wood or other forest products, it’s wise to ask the species and whether it was sustainably harvested.
Be sure to keep your eyes on the woods during your winter walks. I know that you’ll find trees with character, sculpted by Nature.