For example on tree branches like this:
Image from Wikimedia commons
Blender Stack Exchange is a question and answer site for people who use Blender to create 3D graphics, animations, or games. It only takes a minute to sign up.
Sign up to join this communityThere is no doubt that the best result can be generated by using Particle or Physics system, which is a bit complicated to talk about in a few words. A quick-and-dirty way is shown as below: