Leaves that are part of a hedge decay over time. This happens if the leaves are considered to be naturally generated, if they are player-placed or a log is near them, this wont happen.

I drafted a change to always place an oak log underneath every hedge segment, but this may not be the best solution. If the block state persistent could be set to true, theese leaves wont decay.

Is the world editor currently capable of setting block states? (If yes, I would be happy to create a PR 🙂)