If farmers plant trees on a field they can regard the land as their property provided they can prove that the trees are theirs.
(they; can regard; the land) (their property; provided; ) (they; can prove; that the trees are theirs) Context(they can prove,List([86, 100))):(the trees; are; theirs)
they can prove,List([86, 100))
they their property they the trees
can regard provided can prove are
the land
that the trees are theirs
theirs