Hello mojang , i was playing to minecraft and i create a world in survival and i taked cave type

What I expected to happen was:
i though it gonna have tree on the the world...

What actually happened was...:
*When i launch the game no tree so i can't do my survival on a good world type...

Steps to Reproduce:
1. add a way to get wood without going in a mineshaft
 

thanks for attention , have a nice day

Nathan.