How to minimize the load times impact once you start populating the scene?

I’ve been working in my game for a few months, basically in UI/Inventory things, savegames and other support tools, but my scene is almost empty.
Now I am at the point where I would like to spawn my landscape and foliage to start testing some things, but I know that will add a big penalty in load times.
Then I suspect I will regret when I need to get back to work in other unrelated stuff that requires me to constantly restart the editor and the game.
I’m not sure if there is a way to deal with this issue, it would be great if somehow I could temporarily disable the landscape and related objects in a way the engine doesn’t load them at all, but really doubt that’s possible.
Any suggestions?…-removing.html