dendrology vs vegetation

dendrology

noun
  • the study of trees and other woody plants 

vegetation

noun
  • There were large amounts of vegetation in the forest. 

  • An abnormal verrucous or fibrinous growth 

  • The act or process of vegetating, or growing as a plant does; vegetable growth. 

  • Plants, taken collectively. 

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