hat tree vs hatstand

hat tree

noun

  • A hat rack; hatstand. 

hatstand

noun

  • A device used to store hats upon, consisting of a vertical pole with a sturdy base to prevent toppling, and an array of pegs to hold the hats. 

adj

  • Crazy, insane. 

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