Hello! You can link the pictures by: pasting the link where you actually uploaded them (prikachi.com, postimg.com, and similar) and then marking the link with your cursor, after you've done so click the underlined URL you see. Now on-topic, about the trees with their leaves torn, this is something people call 'Herobrine', who doesn't really exist in minecraft as far as I know, if these tunnels are 2x2, they may be just a corruption of the world, as well as the trees with no leaves. Finally, if you are playing cracked minecraft which you have downloaded from somewhere 'else', there could be secretly installed Herobrine mods meant to make you freak out.
There is a way to check out where does that tunnel lead to. Just click escape, then Open to LAN, set gamemode on adventure (so if anyone joins he wont be able to grief)
and then enable cheats. After you've done so, enable spectator mode, and just go all the way down. I hope I've helped you!
- Ivanko
