  We describe edge labelings of the increasing flip graph of a subword complex
on a finite Coxeter group, and study applications thereof. On the one hand, we
show that they provide canonical spanning trees of the facet-ridge graph of the
subword complex, describe inductively these trees, and present their close
relations to greedy facets. Searching these trees yields an efficient algorithm
to generate all facets of the subword complex, which extends the greedy flip
algorithm for pointed pseudotriangulations. On the other hand, when the
increasing flip graph is a Hasse diagram, we show that the edge labeling is
indeed an EL-labeling and derive further combinatorial properties of paths in
the increasing flip graph. These results apply in particular to Cambrian
lattices, in which case a similar EL-labeling was recently studied by M.
Kallipoliti and H. M\"uhle.
