I see many big game developers make shitty forests these days. I'm not saying what you did is wrong, I'm trying to just explain what a good looking forest will look like, and realistic look.
You see, natural forests(virgin forests), and those that are only pathed are very dense. Look at this description picture I made.
RED the distance between trees is usually equal or less than three meters, orig pic:
http://imagesfrombulgaria.com/d/113-6/Ea...forest.jpg
Most developers usually make trees that are very distant from each other. They put grass to cover the sparse tree placing. A perfect example of a forest is crysis1(
http://tzelun.com/blog/wp-content/upload.../30rc0.jpg ) IMO. Some ppl may say it's a jungle, but maybe they never went out for a mountain walk. A jungle is like a forest with palms and other exotic plants. If it's not pathed and you aren't Bear Grylls you won't be able to walk past those forests. In the pic above you see that this type of forests has very tiny grass. Also you can see the angle of this terrain is ~20°
YELLOW, despite that the trees grow 90° straith
BRIGHT ORANGE.
Forests are that stacked that you can barely see light when in the centre between trees
BLUE, but there are also blank spots
GREEN, also you can use some leaves-dirt-sticks texture for the ground like in episode2
http://images.anandtech.com/reviews/mac/hl2ep2/osx.png with very short grass.