This character loves nature.
Whether living in the countryside or city, this character opts for many picnics or long walks in the wilderness, or else fascinated inspection of animals and plants about; the character sometimes lives in the wild. Extensive knowledge of animals and plants is common. Prone to The World Is Just Awesome both as a character trait and as something to reveal to others. Trapped in the city, he will often be seen in any park or just Watching the Sunset.
Usually a sign of Goodness, indicating a wholesome character uncorrupted by the Vice City. Mostly a modern trope, found where most members of the audience live in cities and do not have to wrestle with nature's dangers and inconveniences regularly.
Arcadia may suffice for natural settings — all that greenery — though sometimes it is not wild enough, and the Ghibli Hills are required for the character's taste. When it does suffice, the character often has a Green Thumb.
This does not require the character to exert himself — mountain climbing, or canoing, etc — though outdoors sports are popular with many Nature Lovers. Walks, picnics, and even just hanging out may be all that's required. Hunting is also possible, particularly in older works, but the Nature Lover is seldom the Egomaniac Hunter. Compare Outdoorsy Gal.
The Friend to All Living Things is a subtrope with a magical fillip, and the Nature Hero is a subtrope where the character is definitely resident in the wild and so used to it as to have few social skills.
In Three to Triumph Luna stated that she was able to talk to trees and sense their needs and that she believed her magic had an affinity with anything green.
Film - Animated
Princess Mononoke's San was literally Raised by Wolves after her parents threw her at Morro's feet, to save themselves, when they were caught trespassing in Morro's forest. She's even the poster child for the Nature Hero trope.
In Tangled, Rapunzel is in ecstasies everything she finds in nature. To be sure, that's part being out of the tower.
Kristoff's character bio in Frozen describes him as "a true outdoorsman". This is also justified since he was raised by trolls.
Film - Live Action
Julie Baker in Flipped is very attached to the sycamore tree at her bus stop. Ever since Juli retrieved a kite at the uppermost branches, she has loved the view. She tries to stop the workers from cutting it down and once they do she isn't the same for weeks but Juli's spirits are lightened when her father paints her a picture of her sycamore tree.
L. M. Montgomery's Anne of Green Gables is familiar with every inch of the woods about Green Gables. At the end of House of Dreams, Gilbert, describing a new home to her, carefully cites all the trees about it.
In Poul Anderson's "The Pirate", Trevelyn finds the alien ruins a bit odd, because they had no gardens or parks, even though they obviously loved and had a care for landscapes, and used floral motifs extensively. He reminds himself that they were, after all, aliens.
She told me that having a considerable taste for the Beauties of Nature, her curiosity to behold the delightful scenes it exhibited in that part of the World had been so much raised by Gilpin's Tour to the Highlands, that she had prevailed on her Father to undertake a Tour to Scotland and had persuaded Lady Dorothea to accompany them.
In John Varley's Steel Beach, humanity has been kicked off of Earth, and nature is only available in small, artificial "disneylands". David Earth, the leader of the Earthists, loves nature so much that he has bio-engineered grasses growing on his head; has giant breast implants to represent Mother Earth, with more plants growing on them; has animal skin cells that grow fur implanted on his arms and legs; and has several varieties of insect, and even a few rodents living (and going to the bathroom) on him at all times. He brings nature (or as close as one can get) with him wherever he goes.
Heidi: The title character actually becomes literally homesick to the point of sleepwalking while living in the city.
In Devon Monk's Allie Beckstrom novel Magic Without Mercy, Allie quips about the "great outdoors" when they have to hike somewhere.
Rafael from Gives Light, who lives on an Indian reservation. He loves nature to such a degree that he knows everything there is to know about the wildlife and hates being indoors for too long (even in his own house).
In The Changeover, it's implied that all witches have a closer relationship with nature. As a child, it was one of the things that set Sorry apart from his foster parents, and later on was an excuse for the abuse he suffered.
In Robin McKinley's Sunshine, Constantine's stated reason for living near New Arcadia was the natural beauty about it.
In Andre Norton's Catseye, the Rangers. They carefully cultivate Tikil as a luxury port for the rich because it helps them protect the wild.
Shallan Davar in The Stormlight Archive loves to get out of the house and sketch animals, and seems to be the first person to notice the principle of symbiosis (or at least she'd never heard of the concept before, though the repeated extinction of 90+% of humanity has resulted in a certain loss of knowledge).
And this, our life, exempt from public haunt, finds tongues in trees, books in the running brooks, sermons in stones, and good in everything.
The Legend of Zelda: Twilight Princess: According to official supplemental material, Ilia spends much of her time at the spring, just outside the village, where she bathes Epona. She also pitches in at the ranch, on occasion.
In Sid Meierís Alpha Centauri, two factions turn their affinity for nature into a powerful strategy, since the ecosystem is sentient and the most common lifeform is a swarm of psychic mind eating worms.
"Loves the Outdoors" is among the traits a Sim can have in The Sims 3. Unsurprisingly, said Sim receives a mood boost for being outdoors.
In Valkyria Chronicles, there are two types: the Nature Lover, like Welkin (or Country Bred, like Alicia), who can get a temporary boost from being in a natural setting, and the Child of Nature, like Largo, who can temporarily lose effectiveness when not in a natural setting.