Anytime bark is damaged or missing is stressful for a tree. The outer ring including the bark is where the transport of water and nutrition take place. If the inner portion of the tree is exposed, it will dry out and can split similar to what happens to a piece of firewood as it seasons. If the damage is sufficient, then the leaves are not getting adequate water and nutrients from the soil and small than normal leaves could be the result. Leaves may also not be the deep green you expect. A certified arborist can evaluate your tree and provide appropriate suggestions.
