Humans are highly unnatural creatures. We tend to forget this fact. We are highly unnatural in the sense that we are conditioned by society and the historical circumstances in which we find ourselves. Birds and trees and other creatures of nature are not conditioned in this way. Whereas nature has no control over its own history, humans do. As Feuerbach wrote in his Theses on the Reform of Philosophy, in a line that resonated with Marx, "Man as a being sprung from nature is a creature of nature, not a man. Man is the product of man, of culture, of history."
Though the human essence is determined and expressed through man's social relations, man is nonetheless in some sense a creature of nature. People have always felt a peculiar sensation when they have spent days among forests and lakes. There is something invigorating about it; something that ever inspires reflection and wonder.
For me, time spent in the woods of northern Minnesota (yes, in a modern, well-stocked cabin), reminds me of the primordial fact that everything humans make requires a tremendous amount of work and activity, which depends upon community. Nature has to be constantly worked on to make way for the trappings of human society. In a sparsely populated area, it is easier to observe the fact that people are sustained by their relations with other people, by cultural activities and rituals, and the memory of times past; in the woods, utter solitude can be death to man, can sap the humanness from him. Nature is a relentless process indifferent to the concerns of humans. Humans cannot live by nature alone.