Ironbark

This article is about species of trees in the genus Eucalyptus. For other uses, see Ironbark (disambiguation).
E. crebra bark

Ironbark is a common name of a number of species in three taxonomic groups within the genus Eucalyptus that have dark, deeply furrowed bark.[1]

Instead of being shed annually as in many of the other species of Eucalyptus, the dead bark accumulates on the trees, forming the fissures. It becomes rough after drying out and becomes impregnated with kino (red gum), a dark red tree sap exuded by the tree.[2] The tree is so named for the apparent resemblance of its bark to iron slag. The bark is resistant to fire and heat and protects the living tissue within the trunk and branches from fire. In cases of extreme fire, where leaves and shoots are removed, the protective bark aids in protecting epicormic buds which allow the tree to reshoot.[3]

Being a very dense, hard wood, a length of ironbark is often used as a bug shoe on the bottom of a ship's skeg to protect it from shipworms.[4] Ironbark was widely used in the piles of 19th and early 20th century bridges and wharves in New Zealand.[5] It was widely used for railway sleepers in eastern Australia in the 19th and 20th centuries due to its durability; while other timber sleepers had to be replaced every 7-12 years, ironbark could last 30 years.[6][7]

  1. ^ Ian Brooker, "Botany of the Eucalypts" in J.J.W. Coppen, Eucalyptus, 3-35, Boca Raton, Florida: CRC Press, 2002 ISBN 0-415-27879-1, p. 31
  2. ^ CSIRO Forest Products Newsletter 1946
  3. ^ J.B. Reid & B.M. Potts, "Eucalypt Biology" in Reid et al. (eds.), Vegetation of Tasmania, Australian Government, 2005, pp. 198-223
  4. ^ "AFSC Historical Corner: Scoter, the Agency's Bristol Bay Boat". NOAA. Retrieved 6 April 2018.
  5. ^ "Report 05-116 collapse of Bridge 256 over Nuhaka River Palmerston North-Gisborne Line" (PDF). Transport Accident Investigation Commission. 6 May 2005.
  6. ^ Report on the Construction and Progress of the Railways of New South Wales from 1866-1871, Inclusive. New South Wales. Dept. of Railways and Tramways. 1876. p. 52.
  7. ^ Morris Lake (2019). Australian Forest Woods: Characteristics, Uses and Identification. CSIRO. p. 96. ISBN 9781486307791.