This passage poetically describes the flow of oxygen and carbon dioxide as a kind of long, cyclical breath between people and the trees, a form of living reciprocity in action. The third man that Robin asks suggests that another way to practice reciprocity (which is essentially what her citizenship question is about) is to simply be grateful for the gifts of the land and to
enjoy them. Community is an important aspect of this enjoyment, as the gift is passed on to and shared with others.