what is the relation between the brothers in 'As You Like It'

It is clear that at the beginning of this excellent comedy Oliver and Orlando are not the best of friends, in spite of their sibling relationship. Note the way that in Act I scene 1 they fight, and Orlando, having his brother trapped in some kind of wrestling hold, tells us that his brother has committed the following crimes against him:

My father charged you in his will to give me good education. You have trained me like a peasant, obscuring and hiding from me all gentleman-like qualities. The spirit of my father grows strong in me, and I will no longer endure it!

Clearly the hatred that they feel for one another is expressed through their behaviour and the words they use for each other, such as when Oliver insultingly calls his brother a "boy" and he tells the Duke that he hates Orlando just as much as he does, knowing that this will be bad for his brother.

However, the power of the Forest of Arden to transform characters is shown strongly in Olvier's change of heart and his softening of his attitude towards Orlando. Through what he sees and learns in the forest, and through meeting Celia, he comes to love his brother and regret his past actions towards him, even wanting to give the estate and wealth of their father, that previously he had kept to himself, to Orlando alone:

It shall be to your good, for my father's house and all the revenue that was old Sir Rowland's will I estate upon you, and here live and die a shepherd.

Thus by the end of the play, one of the central conflicts, that between Orlando and Oliver, is resolved as they are restored to loving siblings, which is in direct contrast to how they began the play.