The man appears to be passionately celebrating nature as a wall of water roars down on him through the trees. (Actually, he is throwing large rocks at the falls -- the big tree at right has obscured a rock in flight, leaving him to echo the thrust of the branches with both of his outstretched arms.) He seems so small, while the wall of water and the trees around him are so large. I wanted to express the simple human desire to exult in nature.