This looks familiar and someone may have posted it previously, so forgive me if it is already up. I searched, but couldn't find it. Let me know if it is under a different name or something.

From Stitched on the RPTools forums:

Hey all,

Found this little bit of software that generates procedural trees, with shadows (Windows only, sorry Mac and Linux users).

Software located here: http://www.frecle.net/treed/tree%5Bd%5D-setup300.exe

More info. on it here : http://www.frecle.net/forum/viewtopic.php?t=780

If you swing the camera to its highest limit, you can use Gimp or another screen-capture software to rip an image. With the solid grey backdrop, it's dead simple to apply a Colour to Alpha filter on it.