Can't read any of the values with the screengrab reduced that small.

Firefly (Pro2014GameDev) won't acknowledge PNG's alpha. It seems to be defaulting to a black background in the image map preview window. You might get decent results by plugging it into transparency, with falloff set to zero, and be sure to set specular value to zero, or at least restrict the specular with the transmap.

If the trees aren't sufficiently opaque, some math nodes can exaggerate the lightness of the trees and/or the darkness of the alpha.

edit: cross-posted :)

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5