For each separate tree You would like to separate into its own database:
- Create a new separate database
- Choose Tools (or Command Pallette)->Count Trees->Highlight a Start Person->Click Go to tree
- With your mouse pointer, drag that Start Person out of source database across to new database window.
- Answer<- Who do you want to copy with ->Everyone in the same tree as Start Person.
- Rinse. Repeat for all Trees.