While PrusaSlicer doesn't directly support tree supports for FDM/FFM printing, there is a way to work around it and make PrusaSlicer create tree supports.
1. In PrusaSlicer create a new printer profile for the Prusa SLA printer.
2. Set the bed size to the same as your FDM/FFM bed size.
3. Import the STL into the SLA profile and generate the typical SLA tree supports. I like to increase the support size from 1mm to 2mm as it'll print better. You can also orient the model for best printing with FDM/FFM.
4. Once everything is set as you want, export the plate as an STL with the supports.
5. Switch over to your regular FDM/FFM profile and import the STL you just exported.
6. The STL now has tree supports and can be printed on your FDM/FFM printer.
