I read the sticky on render settings and tried several different things, but the trees I am using (Xfrog) show up very black. You can only see hints of their true color. Along with that, the shadows seem too dark to me as well. Does anyone have any hints?
It appears that the sun is behind and to the right of the plants. You could try adjusting the sun position. I don't know which xfrog plants you are using, but normally there is no translucence for the needles(or leaves). Go to your parts shader and check the shader for the needles and you will probably find 0 for the translucence. You can adjust that to your liking.
It's hard for me to make out details in your image, but if you do a close-up of the needles and they appear to have black squares around them, you'll need to create a mask for your needle image.
Thanks, Ill look into that opacity issue. I know they do come with opacity masks, but perhaps they arent hooked up correctly, as I am unfamiliar with terragen material networks.