alpenstock vs blackthorn

alpenstock

noun
  • A stout adjustable walking stick with a metal point, used by mountain climbers and walkers in hilly or uneven terrain. 

blackthorn

noun
  • A stick or staff taken from this tree. 

  • A large shrub or small tree, Prunus spinosa, that is native to Europe, western Asia, and north Africa. It has a dark bark and bears thorns. 

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