How to create interactive foilage? Cuttable/Regrowable grass and trees

What is the theory behind making grass that you can cut and will grow back after some time and trees which you can chop down and remove the stumps?

Basically I would like to know what things I need to use and do to create plants that have various states of existence and remove them altogether.

Thanks for any help.

I’m really not sure about this, but I think you can make something similair with morph target.