afforestation vs agroforestry

afforestation

noun
  • The act or process of creating a new forest where none had existed before, or reforestation of areas long deforested. 

agroforestry

noun
  • An agricultural approach of using the interactive benefits from combining trees and shrubs with crops and/or livestock. 

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