Please, try creating the Forest object again. It has some transformations (rotation and negative scaling) that seems to affect in some way to the item's alignment.
Once recreated, the alignment works correctly but i just noticed the separation between items is not exact (you can check it at the spline's end). This error seems caused by the Max function used for interpolating splines, because the Normalize Spline modifer suffers the same problem. Sadly, we can't fix it.