Tank you for the comments!

@Rayraz: You're right, it's to light for the forest where the scene is. I'll try to fix it with 2D trees behind the camera. The shadow the tree makes the scene a bit more realistic, unfortunate also more complex, and bryce crashes...
I'll try again and hold my fingers crossed. 

@Wildman2: I'll made the hourglass with supports, but it looks a lot better without them. : )
And how exactly would you place the parallel lights? I don't get that one.