"Family Tree" of 'FamilySearch' is a, SINGLE, "One" World, PUBLIC, "Tree".
All Users/Patrons can view/access ALL the "Deceased" individuals/persons in "Family Tree" of 'FamilySearch'.
And, there ARE separate, 'standalone' (ie. that are UNLINKED/UNCONNECTED), "Trees", in the "Genealogies" Part of 'FamilySearch', that have been supplied by Users/Patrons, for research purposes.
Those separate, 'standalone' (ie. that are UNLINKED/UNCONNECTED), "Trees", can also be accessed/viewed by ALL Users/Patrons; as, they are PUBLIC.
Please explain what you mean by, either,
▬ How to view public trees
▬ How to access public family trees
ps: Related 'Question'
How to view public trees