Swiss pine vs stone pine

Swiss pine

noun
  • A pine tree of the species Pinus cembra, native to alpine Europe, North Africa, and western Asia. 

stone pine

noun
  • A species of pine native of southern Europe, Pinus pinea. 

  • Swiss stone pine (Pinus cembra) 

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