Eugene d’Ors 1882-1954
Tree bark has many forms. Some of these are:
- Smooth – American beech, yellowwood
- Smooth with a peeling outer layer – paper birch, sycamore, paper bark maple
- Fissured – oaks, redbuds, some maples
- Interlacing ridges – walnut, linden
- Small to moderate scales – firs, spruces
- Large scales – pines, some cedars
- Flexible narrow strips – many junipers, dawn redwood
- Rigid long plates peeling up from the bottom – shagbark hickory, some false cypress
Bark is the main factor determining which trees are struck by lightning. Water is a much better electrical conductor than wood. Smooth bark trees get uniformly wet. Lightning travels through the water and into the ground with little or no damage to the tree. Bark that has shallow or connected fissures also lets the electricity travel through the water and into the ground. Bark with deep, unconnected furrows not does not give lightning a path to the ground. The electricity penetrates the bark and travels through the sap. This heats the tree and may even start it on fire. The damage can be substantial, even deadly. Oaks, with their deep rough furrows are struck by lightning more than any other genus.
Tree bark is very useful to humans. We use it for medicine, nutrition, building materials, canoes, dyes, fibers for baskets, clothing and ropes, and the ornamental bark of many trees for landscaping.
Bark is also very useful for tree identification in the winter. Trees have opposite branching (maples, ash, dogwood, horse chestnut) or alternate branching (all others). With this concept and a key to tree bark you can put most trees in their genus and often in their species.
Include looking at bark when you look at trees. The more you look, the more interesting it will be.