Actually I'd say that somewhere in between is best. I have found ginseng in woods so thick you couldn't get through it, although that isn't the norm. if there are alot of plants growing on the forrest floor then that probably means that those woods are getting to much sun. Ginseng doesn't like too much sun. If there are few plants on the floor then it may not be getting enough sun.
I can tell you this, you never know if a woods has ginseng in it until you look. I've been to places that I would have sworn there was no ginseng and find it all over the place. We found a pine forrest last year that was loaded with ginseng (that's abnormal) and on the other hand you can go someplace that seems ideal and not find a thing.
The people on this site can tell you and I would agree that it's true. Once you get a little experience you can walk into a woods and almost feel that it's there. I know that probably doesn't help, but it's true.
Woods with walnut, beach, tulip trees. If you see ferns growing or jack in the pulpit... or a really strong sign is if you can find yellowroot. Around here Mayapple is everywhere, but it can also be a good sign. There is a plant called a pointer, it has white berries on it. if you find that then you're definitly in the right place. The old timers call it a pointer because it's suppose to point to ginseng.
Also, look along deer paths or Find a nice shady hill that overlooks a water source like a creek, stream or pond.
Finally I can tell you that you might find ginseng growing about anywhere. I have even found it growing in gravel and even grass.
Look around dead tree stumps and fallen timber that is rotting. Don't be content with just looking in the wide open. Move stuff around, look under larger plants, small trees. walk the same path from different angles. There is a reason we call it \"hunting\" ginseng.
Good luck.