So I got rid of a ton of trees in my farm in Stardew Valley. I also removed all the acorns and used them all in a bunch of different things. And now I can't find any more Oak Trees anywhere in the world and it's spring year 2.
I don't think it's possible to completely eliminate trees from the game, but you might have to wait a while. Some things to check:
- Just wait for the seasons to turn; I believe you may randomly spawn new oak saplings even if there's not a mature oak around to seed it.
- Make sure you didn't overlook the trees in the Forest, which you can also cut down and which also respawn eventually.
Oaks may respawn on your farm as the seasons pass. This typically happens from Winter to Spring, by my observations.
You can also find them scattered around the maps outside of your farm. These trees can be tapped or cut down, and I'm pretty sure that they re-grow much faster than the trees on your farm if you do cut them down. They may drop Acorns, which may be used to plant new Oaks.
Finally, if all else fails, the traveling merchant (found in the north-western part of the forest, which is south of your farm) occasionally sells Acorns for a random amount of gold, between 100 and 1000g per seed. This is the game's fail-safe to ensure that oaks cannot go 'extinct', though even 100g for an Acorn is quite outrageous under normal conditions. (I never throw 'seed' type items away, personally!)