It starts with asking how did people in the pre-Christian world understand the gods? Part of that, part of where the gods exist, is in nature.
Nature worship and god worship have a lot of overlap. The bodies of the gods were in pivotal natural phenomena and manifested in a myriad of smaller and more localised aspects. There were big differences in interpretation of phenomena, and a large space for the creative and the novel (let alone the poetic) in Classical, and wider European, paganism.
>35 . The 35th introduces two shepherds grazing under Mt. Lysson in the Ephesian territory who spot a swarm of bees in some deep and inaccessible cave. However, one of them gets into a basket to go down, and well tethered he descends. The one who descends finds honey and also much gold, and filling up the basket three times he called for it to be drawn up. When the gold was finished he shouted that he himself was going to get in, but as he said it the idea of treachery came to him, so he put a stone in the basket instead of himself, and called for it to be drawn up. When it was near the crown, the lifter let go. Then, thinking he had killed the other he went away to some gorge and buried the gold. He then crafted plausible excuses to use with those who asked about the disappeared shepherd. Completely at a loss how to save himself, the shepherd in the cave was commanded by Apollo in a dream to slash his body with a sharp rock and to lie quiet. When he does what is commanded, vultures grabbed onto him as to a corpse with their claws; some to his cloak, others fixing onto his clothing, they lifted up and bore him safe to the hollow below. He came to the archive and told everything. And the Ephesians questioned the plotter and punished him after making him divulge the buried gold. Half the gold they gave to the wronged man, and and other half they allotted to Artemis and Apollo. The rescued shepherd, now very rich, installed an altar of Apollo at the summit of the mountain, and he called it Gypaieus (Vulturian) as a memorial of those who lifted him up together.
(from the epitome of Conon in Photius' 'Bibliotheca')
is a good example of the gods in nature, Apollo acting through a flock of vultures, which then ends in the building of an altar on the mountaintop. The magical in nature, as the sacred in nature, as the gods in nature.
Even more directly you get things like:
>"If you have ever come upon a grove that is thick with ancient trees rising far above their usual height and blocking the view of the sky with their cover of intertwining branches, the loftiness of the forest, the seclusion of the spot, and your wonder at the unbroken shade in the midst of open space will create in you a sense of the divine (numen). Or, if a cave made by the deep erosion of rocks supports a mountain with its arch, a place not made by hands but hollowed out by natural causes into spaciousness, then your mind will be aroused by a feeling of religious awe (religio). We venerate the sources of mighty rivers, we build an altar where a great stream suddenly bursts forth from a hidden source, we worship hot springs, and we deem lakes sacred because of their darkness or immeasurable depth."
(Seneca the Younger, Letters 41.3)
or if you go to Burchard's Corrector in the aftermath of paganism (c. 1012ad) you get examples like:
>Canon 57 [66]: “Have you gone to any place to pray other than a church or some other religious place that your bishop or priest showed you; for example, to springs, rocks, trees, or crossroads; and have you burned candles or small torches there to venerate that place, have you brought bread or some other offering there, have you eaten there, or sought anything there for the health of the body or the soul? If you have done this or approved of it, you should do penance for three years on the appointed fast days.”
Neither of the last two are very distant from what is written off as ahistorical modernising nature worship.