A thing is deemed to be affixed to land when it is attached to it by roots, as in the case of trees, vines, or shrubs, or imbedded in it, as in the case of walls, or permanently resting upon it, as in the case of buildings, or permanently attached to what is thus permanent, as by means of cement, plaster, nails, bolts, or screws.
N.D.C.C. § 47-01-05