Answer:
One tree is taller than the other trees and therefore gets more sunlight whilst the trees below are in the shadow of the taller tree.
For example, a toucan has a much larger beak than a Malachite Kingfisher. They both eat nuts but there is not enough to go around the rainforest! So, the toucan has the advantage because of its large beak. This way, the competition is always in the toucan's favor, but the Malachite Kingfisher must fight for its survival!