ACOM member tree queries are best posted on the Member Tree board. This board is for rootsweb world connect.
Regardless, for any tree you want to delete, and do this on the site, not via the web browser in FTM.
1)- select and open the tree
2)- There is a pull down menu *Tree Pages* to the right of the tree name.
3) Pull down and select *Tree Info*
4) on the right side mid-page, find *Delete Tree* in red. To proceed further, you should have your username and password handy, you'll be asked for it to delete the tree.
Deleting a tree doesn't affect another, however it appears you have them linked to FTM. I would turn off auto-sync in FTM before deleting.
If you look at your member profile, your trees are listed. This might help you see which ones to delete.