Same question as TreeKiller64, but for an Acer Palmatum Dissectum that has a probable 6" trunk base and no visible graft scar. I say probable as I have not finished clearing the lonicera, helix, azalea and cotoneaster growing in that area so I can not yet measure the base flare. As far as I know, the tree has been in that spot for more than 10 years.
Based on previous digs in that general area of my garden, there should be no vertical tap root. I have to dig it out this year or next year latest as this is an area we plan to totally redevelop over the next 3 years.