Salem

Hi,

Is there a way to plant new tree's yet?.. I'm I little worried the trees near my claim are almost gone.

and also...

Is there a way to dig for granite?? As far as I know there is Lime and Stone dig sites but not granite.
The granite boulders I found nearby ran out already.

Not yet and no

Then again, what is an effective method to find granite?

I grab my sled, go to nearby badlands, find boulders and haul them to my base. If you don't have badlands nearby then you will run out of boulders in the area quickly.
If you have 2 accounts then you can make a character on second one, travel to some badlands with it, make lean-to there, and find boulders with it, chip granite, and trade it to your main through Boston. If you run out of boulders then simply change location.