Why are sound waves difficult to block

You cant distroy it so it can make it throw many things but in a forest there a so many trees so they block trees

Sounds propagates through some kind of medium. Usually it's air, but it goes just as well through solid objects like walls, windows etc. A soundwave will compress the (air) molecules in front of it, and if this increased density wave hits your ears, you register it as sound. Solid objects like walls are a lot denser than air, this means that they will damp a wave, but also carry it easier.