  We investigate the von Neumann entropy of a block of subsystem for the
valence-bond solid (VBS) state with general open boundary conditions. We show
that the effect of the boundary on the von Neumann entropy decays exponentially
fast in the distance between the subsystem considered and the boundary sites.
  Further, we show that as the size of the subsystem increases, its von Neumann
entropy exponentially approaches the summation of the von Neumann entropies of
the two ends, the exponent being related to the size. In contrast to critical
systems, where boundary effects to the von Neumann entropy decay slowly, the
boundary effects in a VBS, a non-critical system, decay very quickly. We also
study the entanglement between two spins.
  Curiously, while the boundary operators decrease the von Neumann entropy of L
spins, they increase the entanglement between two spins.
