So it's not herobrine.
Like I said, I've seen plenty of tunnels similar. And there was a time when a single missing block on a tree would cause the leaves to despawn.
If you or another play breaks even a single block of wood, then the trees.will lose leaves. It could have also been a mob. I've seen plenty of 2x2 tunnels spawned it, so that's normal.
People make up stuff with herobrine, or think they saw him because of their friends, or because they really wanted to.
He isn't real. He is only in mods.
Mine is Sweden.