in Thoreau’s Journal:

To insure health a man’s relation to nature—must come very near to a personal one—he must be conscious of a friendliness in her—when human friends part or die she must stand in the gap to him. I cannot conceive of any life which deserves the name, unless there is a certain tender relation to nature— This it is which makes winter warm—& supplies society in the desert & wilderness— Unless nature sympathizes with & speaks to us, as it were, the most fertile & blossoming regions are barren & dreary…