Hornbeam


Hornbeams are hardwood trees in the flowering plant genus Carpinus in the birch family Betulaceae. The 30–40 species occur across much of the temperate regions of the Northern Hemisphere.

Origin of names

The common English name hornbeam derives from the hardness of the woods and the Old English beam "tree". The American hornbeam is also occasionally known as blue-beech, ironwood, or musclewood, the first from the resemblance of the bark to that of the American beech Fagus grandifolia, the other two from the hardness of the wood and the muscular appearance of the trunk, respectively. The botanic name for the genus, Carpinus, is the original Latin name for the European species.

Taxonomy

Though some botanists grouped them with the hazels and hop-hornbeams in a segregated family, Corylaceae, modern botanists place the hornbeams in the birch subfamily Coryloideae.

Description

Hornbeams are small to medium-sized trees, Carpinus betulus reaching a height of 32 m. The leaves are deciduous, alternate, and simple with a serrated margin, and typically vary from 3–10 cm in length. The flowers are wind-pollinated pendulous catkins, produced in spring. The male and female flowers are on separate catkins, but on the same tree. The fruit is a small nut about 3–6 mm long, held in a leafy bract; the bract may be either trilobed or simple oval, and is slightly asymmetrical. The asymmetry of the seedwing makes it spin as it falls, improving wind dispersal. The shape of the wing is important in the identification of different hornbeam species. Typically, 10–30 seeds are on each seed catkin.

Distribution

The 30–40 species occur across much of the temperate regions of the northern hemisphere, with the greatest number of species in east Asia, particularly China. Only two species occur in Europe, only one in eastern North America, and one in Mesoamerica. Carpinus betulus can be found in Europe, Turkey and Ukraine.

Associated insects

Hornbeams are used as food plants by the larvae of some Lepidoptera species, including autumnal moth, common emerald, feathered thorn, walnut sphinx, Svensson's copper underwing, and winter moth as well as the Coleophora case-bearers C. currucipennella and C. ostryae.

Applications

Hornbeams yield a very hard timber, giving rise to the name "ironwood". Dried heartwood billets are nearly white and are suitable for decorative use. For general carpentry, hornbeam is rarely used, partly due to the difficulty of working it. The wood is used to construct carving boards, tool handles, handplane soles, coach wheels, piano actions, shoe lasts, and other products where a very tough, hard wood is required. The wood can also be used as gear pegs in simple machines, including traditional windmills. It is sometimes coppiced to provide hardwood poles. It is also used in parquet flooring and for making chess pieces.

Species

Accepted species:
  1. Carpinus betulus L. – European hornbeam - widespread across much of Europe; Turkey, Iran, Caucasus; naturalized in a few places in US.
  2. Carpinus caroliniana Walter – American hornbeam - Quebec, Ontario, eastern half of US
  3. Carpinus chuniana Hu – Guangdong, Guizhou, Hubei
  4. Carpinus cordata Blume – Sawa hornbeam - Primorye, China, Korea, Japan
  5. Carpinus dayongiana K.W.Liu & Q.Z.Lin – Hunan
  6. Carpinus eximia Nakai – Korea
  7. Carpinus faginea Lindl. – Nepal, Himalayas of northern India
  8. Carpinus fangiana Hu – Sichuan, Guangxi
  9. Carpinus hebestroma Yamam. – Taiwan
  10. Carpinus henryana H.J.P.Winkl. – southern China
  11. Carpinus japonica Blume – Japanese hornbeam - Japan
  12. Carpinus kawakamii Hayata – Taiwan, southeastern China
  13. Carpinus kweichowensis Hu – Guizhou, Yunnan
  14. Carpinus langaoensis Z. Qiang Lu & J. Quan Liu – Shaanxi, China
  15. Carpinus laxiflora Blume – Aka-shide hornbeam - Japan, Korea
  16. Carpinus lipoensis Y.K.Li – Guizhou
  17. Carpinus londoniana H.J.P.Winkl. – southern China, northern Indochina
  18. Carpinus luochengensis J.Y.Liang – Guangxi
  19. Carpinus mengshanensis S.B.Liang & F.Z.Zhao – Shandong
  20. Carpinus microphylla Z.C.Chen ex Y.S.Wang & J.P.Huang – Guangxi
  21. Carpinus mollicoma Hu – Tibet, Sichuan, Yunnan
  22. Carpinus monbeigiana Hand.-Mazz. – Tibet, Yunnan
  23. Carpinus omeiensis Hu & W.P.Fang – Sichuan, Guizhou
  24. Carpinus orientalis Mill. – Oriental hornbeam - Hungary, Balkans, Italy, Crimea, Turkey, Iran, Caucasus
  25. Carpinus paohsingensis W.Y.Hsia – China
  26. Carpinus polyneura Franch. – southern China
  27. Carpinus pubescens Burkill – China, Vietnam
  28. Carpinus purpurinervis Hu – Guizhou, Guangxi
  29. Carpinus putoensis W.C.Cheng – Putuo hornbeam - Zhejiang
  30. Carpinus rankanensis Hayata – Taiwan
  31. Carpinus rupestris A.Camus – Yunnan, Guangxi, Guizhou
  32. Carpinus shensiensis Hu – Gansu, Shaanxi
  33. Carpinus shimenensis C.J.Qi – Hunan
  34. †Carpinus tengshongensis W.C.Cheng – Zhejiang but probably extinct
  35. Carpinus tropicalis Lundell – Mexico, Central America
  36. Carpinus tsaiana Hu – Yunnan, Guizhou
  37. Carpinus tschonoskii Maxim. – Chonowski's hornbeam - China, Korea, Japan
  38. Carpinus turczaninowii Hance – Korean hornbeam, - China, Korea, Japan
  39. Carpinus viminea Wall. ex Lindl. – China, Korea, Himalayas, northern Indochina