How to increase the foliage density afterwards?

Hello,

is it somehow possible to increase the foliage density afterwards? Under Scalabilty is a Button to enable Density Scaling. But if i check it, nothing happens. I read that you can make it over the Command Line, but i want it only for specific Assets and i want it permanently of course. For me as a Bledner user, this is the most normal thing in the world, but i don’t seem to be able to check it here…

I am very grateful for any help!