Tree pine ("Pinus" species) the bark exudes sticky resin which deters attackers whereas in rubber trees ("Hevea brasiliensis") it is a milky latex that oozes out. The quinine bark tree ("Cinchona officinalis") contains bitter substances to make the bark unpalatable. Large tree-like plants with lignified trunks in the Pteridophyta, Arecales, Cycadophyta and Poales such as the tree ferns, palms, cycads and bamboos have different structures and outer coverings. Although the bark functions as a protective barrier, it is itself attacked by boring insects such as beetles. These lay their eggs in crevices and the larvae chew their way through the cellulose
Bark mill used extensively in France, Weldon’s bark-grinding mill, and a device known as a Wiltze’s or Catskill's mill, prevalent in 19th-century America. The Swansea, Tasmania bark Mill processed black wattle bark in colonial times and is now a combined museum. Bark mill Bark mills, also known as Catskill’s mills, were water, steam, horse, ox or wind-powered edge mills used to process the bark, roots, and branches of various tree species into a fine powder known as tanbark, used for tanning leather. This powdering allowed the tannin to be extracted more efficiently from its woody source material. A barker would strip the