Well, Forest uses a 'F' icon as gizmo, but it is displayed only where exists some error condition and the object is not selectable.
The problem of using a standard gizmo as other plugins have, is that perhaps we should change also the creation process: From Add Forest->Pick Spline/Surface as now, to Add Forest->Create Gizmo->Assign Properties. Unfortunately this could mean changing the users' habits and many media content as tutorials, videos and so.
We will think if there is an intermediate solution for adding it.