Would it be possible to have trees sway by giving them several different positions and have them play on a loop? (Similar to how water shimmers and monsters take steps). This would give the game world a much more dynamic feel. 
You could also make wind louder and trees sway more when it gets stormy outside.
			
		

 But thanks for the suggestion! (We already have ideas for making the world more dynamic, we'll see which one will be in the final game.)
 But thanks for the suggestion! (We already have ideas for making the world more dynamic, we'll see which one will be in the final game.)