Re: Birch Grove
Wonderful scene. Yes, it needs shadows on the snow and on the central trunk. I think the flashes of light on the trunks are too prominent, maybe should be somewhat broken or non-existent esp near the base as the sun is pretty low.
The brush and grasses adds to the sense of serenity.
The differentiation of the purple snow in shadow is appropriate, but the land seems to "roll slightly, so the show is in shadow not only from where it is in front of the background, but the grasses will cast a shadow, as will the little variations--dips, etc, of the shadowed snow on the ground.
I wonder if the yellow on the snow is a bit too bright. Maybe a whisper of a purple glaze over the yellow on the snow would lower that bright chroma esp on the two center streaks.
I really like your sky, esp the gray area, the clumps of snow on some bushes/brush.