crossbeam vs summertree

crossbeam

noun
  • A horizontal structural beam that runs perpendicular to the primary support beams; a girder. 

  • A beam laid across the bitts, to which the cable is fastened when riding at anchor. 

summertree

noun
  • A horizontal beam brought even with the face (breast) of a wall, to support a wall above a gap or opening; a beam bearing a load above. 

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