Computer freezes or program crashes when i try to add tree assets

I’m creating a scene for a game i’m developing, and have gotten to the point of adding tree assets,however once i try the program either freezes or crashes…

Is there by any chance a way i could add the trees without it crashing, or do i have to upgrade my hardware. if so; what would i need to look for in a new computer to ensure the program runs smoothly in the future?