Project C.A.R.S.

[Googolplex]

Those trees do, in fact, look like flat textures.

You can tell because the perspective on them don't change as the car moves or turns.

I can't say that because I never played an alpha version.
But the devs said, that the trees actually are just placeholders and they become replaced in later builds.

It is wrong to say, trees are generally flat textures. There are many games with real tree models.