This is a very specific suggestion that needs a bit of a back story.
So I'm out at the farm with the chicken coop & well and driving on the driveway as nature begins its reclamation. I start running into saplings to the sound of glass breaking. So I jump out of the vehicle with my newly acquired ax to chop down the tree but the ax does not interact with the sapling no matter what I try. I chop down a couple trees just to make sure it is a not a bug.
So my suggestion is one of two:
1) Have the vehicle take a small amount of damage and destroy the sapling (preferred-seems a bit more realistic)
2) If the tree is large enough to 'crash' the vehicle, have the ax be able to interact with it.
If you go with option #1, I would think driving over a path would keep it rather clear of all growth.