it keeps a tree warm
purpose of outer bark
That depends on the species and size of the tree. For instance "cork oaks" have a very deep outer bark while "silver birch" outer bark is paper thin.
the role of this outer for bark is i dont know
Bark
Bark, as of a tree; hence, an outer covering., Bark; rind; specifically, cinchona bark., The outer or superficial part of an organ; as, the cortex or gray exterior substance of the brain.
The outer protective covering of a tree is called the bark
The outer bark of a tree protects it.
It is normally called the tree's bark.
bark
bark
bark.
The six layers are pith, cambium , inner bark or phloem outer bark , bark
Bark