Using the well-proven methodology of drawing a line on the side of a post-it, we can observe that the man in the tree is precisely the same height in perspective as the man in the white shirt standing on the stone wall.
Allowing for the tree being nearer to the photographer the tree we can judge that the man in the tree, while appearing larger due to a trompe l’oeil, is in fact perfectly in scale with the wider photograph.
Further using the post-it methodology, we can conclude that he is standing some 17 -18 ft above the head of the person immediately below him in the crowd. Thus he is some 24ft above the ground. The man is wearing sunglasses because he is cool, or at least as cool as you can get in South Galway hurling country.
He is leaning against a deeper branch rather than the more obvious branch to the front of the perspective and is in a natural pose for the position.