Hi! I know a fair bit about plants and am quite elated at how well the trees are executed in terms of shape and their occurences.
Here are some ideas or suggestions:
1. Willow or Poplar trees. Notoriously soft wood (less firewood yield), Poplars grow to great size, Willows could prefer proximity to water.
2. Cattails like to grow near or in water and worldgeneration reflects that, so I think being required to keep them near a body of water when replanting would only make sense.
3. As it is now you have to find pines with resinous logs. Freshly grown trees don't have them, which makes sense. If you've ever worked with any kind of resinous Conifer IRL however, you may well know that the dont just leak but outright ooze resin when you cut them especially with fresh wood. Apart from that if you want to collect resin from a tree you can just cut through the bark and it'll leak resin out of the cut. In terms of gameplay you could use a knife to cut a resin channel into a log face which then oozes out resin continously exactly in the way it's already implemented. To balance that and to mimic realism moreso the channels (also the ones provided by worldgen) would eventually dry up and if you cut too many into a tree it'll wither and die (no logs for you, I suppose). Also if using stone knifes it has a chance to fail, as a poasibility for including knife quality.
4. I really wonder why flax seeds are split into edible and plantable ones in the game. Surely everyone knows that IRL they are the same. Just give more seeds and have those ones be plantable.
5. Related to 4, Why exactly do games always simplify the gardening process so much, especially complex games like Vintage Story? If you want your turnips, carrots, parsnips, onions to seed, they need to be left to grow for another season, then they'll flower and fruit. IRL you'd need to leave a patch of veggies outside overwinter, ingame it could just be another bunch of days.
6. Tule. This plant isn't very useful ingame as it is, and I keep wondering why it doesn't have more uses. It's terribly inefficent food, it takes forever to make a thatch roof out of it and it doesn't burn well. On a side note, I do really wonder about the plant itself. Me being european I'd never heard of tule prior to this game. I know Phragmites australis which at least nowadays is prolific everywhere (whatever if's english name is). Just out of curiosity, why isn't it that plant?
7. In the spirit of survivalism, it'd be kind of cool to have oaks drop acorns in fall and be able to process them to food.
Alright, that's it. Those are my Ideas for now.