I gave a short answer above, but I wanted to expand on it because I just remembered a Nessmuk quote that I thought was applicable. Indeed, when one is sitting by a fire, relaxing in a nice campsite on a warm summer day, being in nature can be sublime, and to some people spiritual. For me the experience changes drastically as the conditions become more challenging. When I've been pushing through dense bush for days, when I am exhausted, short on water, cold, getting rained on, etc, the spirituality gets lost very quickly. There is a quote from Nessmuk I like:
“...there are some who plunge into an unbroken forest with a feeling of fresh, free, invigorating delight... These know that nature is stern, hard, immovable an terrible in unrelenting cruelty. When wintry winds are out and the mercury far below zero, she will allow her most ardent lover to freeze on her snowy breast without waving a leaf in pity, or offering him a match; and scores of her devotees may starve to death in as many different languages before she will offer a loaf of bread. She does not deal in matches and loafs; rather in thunderbolts and granite mountains. And the ashes of her camp-fires bury proud cities. But, like any tyrant, she yields to force, and gives the more, the more she is beaten. She may starve or freeze the poet, the scholar, the scientist; all the same, she has in store food, fuel and shelter, which the skillful, self-reliant woodsman can wring from her savage hands with axe and rifle.”