culm vs haulm

culm

noun
  • the stem of a plant, especially of grass or sedge 

  • anthracite, especially when found in small masses 

  • waste coal, used as a poor quality fuel; slack. 

haulm

noun
  • An individual plant stem. 

  • The stems of various cultivated plants, left after harvesting the crop, which are used as animal food or litter, or for thatching. 

  • Part of a harness; a hame. 

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