TomasGrizzly's avatar
1. Photographer PoV (though hobbyist, not artist): While they are mostly background, I have some photos (not uploaded yet) with a tree (or group of them) as central subject. Willow and Larch trees have some charm early in april when the fresh leaves start to grow. And while not single tree as centerpiece, the puzzle of various colors a forest becomes in fall has it's charm as well.
2. The only I can think of is Avatar and the Tree of souls. Not sure Nordrassil in Warcraft could be considered a character as much.
3. I'd say it depends on the skill of artist as well as personality of those who see it. I, as someone who likes to visit nature a lot, think that they have its place. If you want to point out some place that looks nice by itself, adding something for sake of having subject might actually make it worse.
4. Really important? Probably not.
5. Can't really say as I live in flat. Even though my grandparents have a garden, never thought about estetic aspect of it, more as source of delicious fruits and vegetables.