Vines on trees don't dissapear when tree is destroyed

I loaded up a new world, so I cut down a tree with vines hanging down the sides, and I waited for saplings to fall, and when all of the leaves of the tree were gone, I started to notice that the vines on the sides weren't dissapearing. I started to tear down the vines one by one afterwards.
(I apologise for having such a bad picture 🙂 )