Your trees appear to be lighted up wrong.
use info_lighting and configure the tree's options to use that as a reference.
(info_lighting should be placed somewhere above your trees)
to further enhance your lighting use advanced compiling options and put this in the vrad parameters under hdr full compile
-StaticPropLighting -StaticPropPolys -TextureShadows
your vrad hdr parameter should look something like this:
-hdr -StaticPropLighting -StaticPropPolys -TextureShadows -game $gamedir $path\$file
these cmds are how Valve compiles their maps
NOTE: it does not have to be an hdr full compile configuration. You can use default and/ or fast compile and add those cmds to the vrad run line.
If this sounds unclear then talk to me on steam