I was just wondering if there is a way to display the changes made using the parralax builder in the editor. Currently the changes only apply when in-game. I created a forest with the parralax builder but the editor basically just shows a blank field with no trees.

I'm not quite getting it. If you add a layer trees to editor then in the game it should show trees immediately. Can you tell me what you're trying to achieve more detaily?

It isn't standard parallax building in RPG Maker so there isn't a way to really do what you're asking for. Even Yanfly's equal to this plugin for MV doesn't do what you're asking for, that is due to an engine limitation, but otherwise intended behavior.