Regularity of powers of Stanley-Reisner ideals of one-dimensional simplicial complexes

Let $Delta$ be a one-dimensional simplicial complex. Let $I_Delta$ be the Stanley-Reisner ideal of $Delta$. We prove that for all $s ge 1$ and all intermediate ideals $J$ generated by $I_Delta^s$ and some minimal generators of $I_Delta^{(s)}$, we have $${rm reg} J = {rm reg} I_Delta^s = {rm reg} I_Delta^{(s)}.$$