Tree bark can vary greatly throughout the life of a tree, often becoming rougher as a tree grows. Only a few trees (such as Beech) retain smooth bark throughout their life.  Below are examples of just a few of the many different bark types.

 

Beech bark stays smooth its entire life, as can be seen on this older tree.	Shagbark hickory shreds its bark in long strips as it gets older.	Pitch pine has large plates.  Epicormic sprouting is also common as can be seen on the left side of this tree.
Persimmon has small blocky plates and often looks like charcoal briquettes.	Tulip-poplar bark displays a pattern of interlacing ridges and furrows that form a diamond shaped pattern.	Yellow birch has a very fine shreddy bark that peels into small strips.