It is the protective structure around the trunk, that is, the bark that can be peeled off from the trunk in the process of wood cutting or processing, including phloem, cortex, periderm and all dead tissues except cork layer accumulated many times from the inside out.
In woody plants, all tissues except cambium are mainly dead tissues, and the bark produced by cork cambium is usually thinner than that produced by xylem in stem.
Bark is the outermost part of stems and roots of woody plants, such as trees. Bark in a narrow sense includes cork, cork cambium and cork inner layer, as well as various dead tissues outside, and bark in a broad sense also includes phloem.
The bark of some plants contains various alkaloids, tannins, dyes and spices, which can be used to extract various medicinal materials, drugs, poisons, resins and so on. Some kinds of bark can also be used to make cork, rope, weaving, making bark boats, drawing bark paintings and so on. , or directly used as decoration.