By Katie Neis
Gray, furrowed, smooth, peeling, scaly, brown, plated, exfoliating, and the list goes on.
Does the bark you love have a smooth texture that lets you rest your back against it when you are sitting in the tree’s shade? Or is it plated chunks that look like armor that tickle your fancy?
Bark is much more than just an afterthought in the evolutionary chain of trees. It provides many visible—and invisible—benefits to the tree. Aside from being a tough weather-proof barrier, the bark traps moisture and keeps air out. This delicate balance can protect the tree from diseases, insect invasion, and even damage from mammals.
Think of how stationary a tree is. Its entire life it never moves. Period. The end. Everything this world throws at it, a tree must not only defend itself from but persevere against. Leaves and bark contain chemical defenses to ward off attacking intruders, and some trees even produce sharp thorns that make them unpleasant to munch on by those who pass by.
Since a tree carries all its nutrients and water through its bark, wounding can be deathly.
Every year during a tree’s life cycle a new tree grows inside the old tree—just under the bark layer that we see. Trees cannot “heal” wounds like a human can. They can only “seal” wounds. In a nutshell, the tree closes off different compartments of wood in order to stop disease and decay from spreading, new bark tries to grow over the wound to seal it off from continued damage. This process is called “CODIT.”
Bark damage that is too great to be sealed over creates decay cavities throughout the tree, cutting off nutrient flow and weakening the tree’s structure.
If your tree has bark damage, mulch and water it regularly to bolster its natural defenses until the wound seals. Do not “dress the wound.” This is an old practice that causes more damage than good.
Be kind to your tree through this tough time. Think of your tree, and its bark, like a mini fortress. With proper establishment, you can solidify your living fortress and protect your new tree for many years to come.
–Neis is a Neighborhood Trees Assistant for Friends of Trees.