The grasdipfoliage-version will most likely not look like a dead tree.

I'd go for the spray version, too. Brushing could be a bit tricky, not because there are so many, but because you cannot reach everywhere. Maybe they will bend into the brush, making more smear then brushing of it.
So ... spray base colour, then spray "highlights". I won't use plain white, cause that might look like frost and a bit too "wintery".
IMHO a cold brown like bleached bone, kommando khaki (if you can get such a spray) or something should be it, but not too much. No warm colours like ie terracotta, etc.
Finally I would put more effort into the bases and they will pull the treess in the right direction.