"Landscape architectural services" means services including but not limited to consultation, investigation, reconnaissance, research, design, preparation of drawings and specifications and administration of contracts where the dominant purposes of such services are:
A. the preservation or enhancement of land uses and natural features;
B. the location and construction of functional approaches for structures, pathways or walkways; or
C. the design of trails, plantings and landscape irrigation. Excluded from the provisions of this section are the services of architects, engineers and surveyors as defined in the Procurement Code.