We humans, the descendants of 55 million years of tree-dwelling ancestors, who lived and died in the open air of the forest, are no longer able to live out in the open. Instead, we crave “a roof over our heads” in the form of a secure canopy that not only protects us from the wind, rain, and snow but also forms a closed, cave-like environment that traps the heat from our fires and protects us from attack by predators.
