  The interaction of open and closed field lines at coronal hole boundaries is
widely accepted to be due to interchange magnetic reconnection. To date, it is
unclear how the boundaries vary on short timescales and at what velocity this
occurs. Here, we describe an automated boundary tracking method used to
determine coronal hole boundary displacements on short timescales. The bound-
ary displacements were found to be isotropic and to have typical
expansion/contraction speeds of \leq2 km s^-1, which indicate magnetic
reconnection rates of \leq 3 \times 10^-3. The observed displacements were used
in conjunction with the interchange reconnection model to derive typical
diffusion coeffi- cients of \leq 3 \times 10^13 cm^2 s^-1. These results are
consistent with an interchange reconnection process in the low corona driven by
the random granular motion of open and closed fields in the photosphere.
