arboriculture vs gardening

arboriculture

noun
  • The branch of horticulture concerned with the planting, growth, and maintenance of trees. 

gardening

noun
  • The process or action of cultivating the soil, particularly in a garden; the care of a garden; horticulture. 

  • Any process of care, maintenance, or curation, especially digitally. 

  • The act of a batsman prodding at the pitch with his bat, typically in order to flatten any bumps. 

How often have the words arboriculture and gardening occurred in a corpus of books? (source: Google Ngram Viewer )