The mottling in the trees is great. I think some of your white's could go darker though (at least on the nearer trees)
I think its amazing to see your traditional skills transfer so well to digital work. I like how you used transparencies to get different effects in the light. I think you're directing the viewer very effectively with the highest value contrast at the edge of the house and the background trees. Very nice!
I love the light in this--so great. Um . . . suggestions . . . maybe those little dark spots farther towards the front could be toned back a little, but they're not really pulling away from the focus of the house, so I don't think you HAVE to do that.
This image has a really nice effect. I with Spencer about the trees in front going darker. I think I would tone down the nearest tree specifically and the two little trees on the right side in front of the house. Nice work!