He is climbing a Brazil nut tree to collect Brazil nuts. They are called Para nuts in Brazil, because they are grown in the province called Para. Brazil nuts grow in a circle in wooden pods. Brazil nuts are sold to other parts of Brazil, and the world. Have you ever eaten a Brazil nut?
He has a piece of palm frond tying his ankles together so he can climb the tree easier. People climb coconut palm trees the same way. It's hard to climb a tree that has no branches along the trunk!