Bark is the vitally important skin of the tree, protecting its insides from drying out or being damaged by fungi, insects or animals. It also protects the tree from extremes of heat and cold.
Like animal skin bark is made up of several layers (the outer layer that we see is actually called ‘cork’), and each layer has an important job to do. The thickness of the bark layer varies enormously; in some trees the bark layer can be almost paper thin, whereas in the giant redwood trees of California it can be up to two feet thick.
Each type (or species) of tree has a different pattern and texture to its bark, so by looking carefully at the bark you can often identify the tree.
If you take the bark off a tree it will do damage to the tree itself which may then die. However you can make and keep an accurate record of the bark by making a bark rubbing, examples of which you can see at the bottom of this page.