The Living Landscape: The secret life of bark
- Kathleen Scavone
- Posted On
LAKE COUNTY, Calif. – Winter allows us to slow down and observe the underpinnings of nature.
With the autumn season's job of coloring, then dropping leaves, now it's easier to study a tree's distinctive covering – its bark.
Depending on the species, a tree's bark can be smooth as wet stone or deeply ridged with character-giving “craters.”
Anatomically speaking, bark – or the tree's periderm – is a protective layer that keeps it safe from disease, dehydration, harmful parasites, pests and pathogens.
According to Glenn Keator's “Life of an Oak,” all trees hold within them cells called vascular cambium which add to the tree's size each year, and a tree's bark secretly holds differing layers consisting of cork and cork parenchyma.
The tree's wood is a complicated coordination of fibers, vessels and cellulose molecules to name but a few parts.
Tree bark often gives us features and hints to identify a tree's species.
The complex compounds that make up bark include tannins, lignins and suberins. Those components have the capacity to both reflect and hold certain wavelengths of light, thereby creating a bark's color.
Some trees, like mature oaks, hold deep ridges and furrows, gaps which are called rhytidome.
Other trees, such as pine, have bark with plates or scales, and flowering dogwood's bark is unusual with its little puzzle-piece plates.
According to Bay Nature Magazine, manzanita trees “are derived from a group of trees, the madrones, that have fossils dating as far back as 50 million years.”
While madrone trees exhibit flesh-colored, smooth bark, manzanita bark is often a deep, red-mahogany color.
Both trees have adapted a special way to protect their lovely, smooth bark surfaces by way of peeling. Each year their bark peels into papery scrolls which protects their smooth surfaces from the ravages of parasites, fungi, mosses and lichens.
While a tree's bark can help to identify it when it is leafless, another way bark can aid in a tree's identification is by its unique smell.
Ponderosa pine is said to give off a unique scent with hints of vanilla, and Jeffrey pine holds a butterscotch smell, while other pine trees may smell of turpentine.
A tree's bark can show age or time in the sun, much like our sun-ravaged epidermis, and similar to us, a tree can sport a callus in response to a wound.
Over time, people have appreciated or been dependent on trees not only for their food and fuel. Trees have "generously" provided humankind with bark for boats and shelter, medicines, cork, cloth, mulch, shingles and so much more.
Sometimes you don't have to look very closely to examine tree bark's nuances; its patterns and textures. Many trees' furrowed, patchy or scaly skin can play host to numerous types of mosses, lichens and fungi, which stand out like a beacon in the woods.
Moss anchors to tree bark like a vivid, velvet cloak. When the season is dry, moss that grows on bark or stone places itself into a phase of dormancy. Then, it awaits life-giving moisture from fog, or rain when it plumps up like a wet sponge.
Trees, those intricate, stalwart life forces, give us much to ponder, so next time you are wandering the woods get up close and personal to a tree, hone in your art of perception and enjoy the varieties, nuances and textures – secrets that each tree has to offer.
Kathleen Scavone, M.A., is a retired educator, potter, freelance writer and author of “Anderson Marsh State Historic Park: A Walking History, Prehistory, Flora, and Fauna Tour of a California State Park” and “Native Americans of Lake County.”