sapling vs seedling

sapling

noun
  • A young tree, bigger than a seedling. 

  • A youngster, especially a male nearing maturity. 

seedling

noun
  • a tree smaller than a sapling. 

  • one grown in a nursery for transplanting. 

  • A young plant grown from seed. 

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