There are some trees, that's why it took you all an hour to find the camp and how the caravan is hiding it, but there isn't a lot of trees in the bandit camp itself. They chopped most of those down for wood, like the light fortifications and the watch tower. That's not to say there's open space; Ssarak would only have the immediate air above the bandit camp to fly around in, and while it's big enough to give sleeping space for a crew of twenty bandits, he's not exactly going to be able to fly freely through the forest. I'd say there's only about 600 or so of space with no trees for Ssarak to be flying around in. The general area of the bandit camp is squarish. 

Also how many of you can see in pitch blackness?