Eventually, if the saguaros survive, their shallow roots may intercept the tree's rainwater and kill it.
(the saguaros; survive; ) (their shallow roots; may intercept; the tree's rainwater; T:Eventually) (their shallow roots; kill; it; T:Eventually)
the saguaros their shallow roots their shallow roots
survive may intercept kill
the tree's rainwater T:Eventually
it T:Eventually