I made a tree house on minecraft. and i wondered if villagers can climb up and down vines. So they can come in and out of the tree house.
Mobs do not use ladders or vines in their path-finding, but if they are pushed by something into a climbable, they will climb it.
From the wiki:
Villagers can climb ladders if they are in their path, like other mobs.
This means if they walk into a ladder or a vine, they will climb it.
However, in your case the villagers will not purposely climb up and down into the tree houses.