6. a. Nothing in P.L.1983, c.337 (C.45:3A-1 et al.) shall be construed to prevent or limit the practice of architecture, engineering, land surveying or professional planning by a holder of a license to practice that profession licensed by this State, but no architect, engineer, surveyor or professional planner shall use the designation "landscape architect" unless licensed as a landscape architect in this State.
b. No municipal or county policy or action purporting to define, or having the effect of defining, the scope of professional activity of architects, engineers, land surveyors, planners, or licensed landscape architects in the preparation of landscape design plans shall reduce or expand the scope of professional practice recognized by the respective boards that regulate these professions.