I’m afraid that there is no easy way of doing . To make blueprint work in editor whole forest creation process must be called from contruction scrip, however in construction scrip you cannot create custom events. Because of that you cannot split work between multiple actors, so whole functionality (creating grid, choosing spots to spawn, adding tree instances etc) must be called from one blueprint as single chain of functions. It should work ok for small areas with low tree density, but larger ones might freeze whole editor.