check you settings in byrce especially antialiasing. check defrag (it may be time to do that) check available disk space (getting low) only use 3d trees in the foreground make 2D objects (as suggested above by agent smith) from photos of trees. properly masked and if your camera doesn't move you can't easily tell. you can even rotate the images a few degrees, rescale and reverse them to give the illusion of more unique trees. also distant trees could be one large 2d object used as a background (mask could be a bear - solid??). also 67 trees? wow that's a lot. when you get done let's see what you get.