What is Bark?
[[File:Pine bark.jpg|thumb|200px|the bark of a [[Monterey Pine]]]] '''Bark''' is the covering of the [[Plant stem|stems]] of woody [[plant]]s, like [[tree]]s. Bark protects the tree. Bark of different plants and trees can look very different, it can be rough or smooth and can have different [[colors]]. It is the outer layer of tree trunks. Most of the bark grows from the [[vascular cambium]]. Some outer parts of the bark sometimes come from a [[cork cambium]]. In the bark are [[lenticels]] which allow gases to move in and out of those inner tissues which have living cells. Bark of one kind or another has been on trees from the [[Carboniferous]] period. It is obvious on stems and branches, and on some kinds of storage organs. {{commons|Bark}} [[Category:Plant anatomy]] [[Category:Plant physiology]] {{biology-stub}}