  We introduce a general notion of a seminorm on sheaves of rings or modules
and provide each sheaf of relative differential pluriforms on a Berkovich
k-analytic space with a natural seminorm, called Kahler seminorm. If the
residue field is of characteristic zero and X is a quasi-smooth k-analytic
space, then we show that the maximality locus of any global pluricanonical form
is a PL subspace of X contained in the skeleton of any semistable formal model
of X. This extends a result of Mustata and Nicaise, because the Kahler seminorm
on pluricanonical forms coincides with the weight norm defined by Mustata and
Nicaise when k is discretely valued and of residue characteristic zero.
