Okay, got my pine trees covered in snow for the scene...
First, I lined them all up, and gave them a spray of white matt paint, but only from above, so as to preserve the natural shadows a bit.
Then I mixed up a bit of snow flock, white glue, and water, following the directions outlined in the "Nuts!" board build outlined in Wargames Illustrated 301.
I liberally wiped the trees down with this mixture, trying to get the outsides as best as possible, and looking out for where overhanging branches might leave empty spots (but that was tricky...)
After that, I gave each tree a good sprinkling with a bit more of the snow flock.
I'll wait a bit and then give them a touch of varnish, I think, to help hold everything in place.
Overall I am pleased with how they turned out!