alder

1 wood of any of various alder trees; resistant to underwater rot; used for bridges etc

2 north temperate shrubs or trees having toothed leaves and conelike fruit; bark is used in tanning and dyeing and the rot-resistant wood [syn: alder tree]

English

Etymology

From alor

Pronunciation

• (UK): [ˈɔːldə]
• (US): [ˈɔldɚ]

Noun

1. Any of several trees or shrubs of the genus Alnus, belonging to the birch family.

Related terms

• Andean alder
• black alder
• Caucasian alder
• common alder
• Formosan alder
• green alder
• grey alder
• hazel alder
• Himalayan alder
• Italian alder
• Japanese alder
• Mexican alder
• Nepalese alder
• oriental alder
• red alder
• seaside alder
• white alder

Translations

Danish

Noun

alder

1. age

Norwegian

Noun

1. age

Derived terms

• aldring

Alder is the common name of a genus of flowering plants (Alnus) belonging to the birch family (Family Betulaceae). The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate zone, and in the New World also along the Andes southwards to Chile.

Alder leaves are deciduous (not evergreen), alternate, simple, and serrated. The flowers are catkins with elongate male catkins on the same plant as shorter female catkins, often before leaves appear; they are mainly wind-pollinated, but also visited by bees to a small extent. They differ from the birches (Betula, the other genus in the family) in that the female catkins are woody and do not disintegrate at maturity, opening to release the seeds in a similar manner to many conifer cones.

Varieties

The best-known species in Europe is the Common or Black Alder (A. glutinosa), native to most of Europe and widely introduced elsewhere. The largest species is Red Alder (A. rubra), reaching 35 m (the tallest is 32 m) on the west coast of North America, with Black Alder and Italian Alder (A. cordata) both reaching about 30 m. By contrast, the widespread Green Alder (A. viridis) is rarely more than a 5 m shrub.

Uses

Alders establish symbioses with the nitrogen-fixing Actinobacteria Frankiella alni. This bacteria converts atmospheric nitrogen into soil-soluble nitrates which can be utilised by the alder, and favorably enhances the soil fertility generally. Alders benefit other plants growing near them by taking nitrogen out of the air and depositing it in the soil in usable form; fallen alder leaves make very rich compost.

Alders are sturdy and fast-growing, even in acidic and damaged sites such as burned areas and mining sites. Italian Alder is particularly useful on dry, infertile sites. Alders can be used as a producer of simple bio-mass, growing quickly in harsh environments.

Alder catkins are one of the first sources of pollen for bee species, especially honeybees, which use it for spring buildup. Alders are also used as a food plant by some Lepidoptera (butterfly and moth) species, see list of Lepidoptera that feed on alders. Alders are also grown in gardens, and are sometimes made into bonsai.

Alder is a preferred wood for charcoal making, formerly used in the manufacture of gunpowder, or for smelting metal ores, now used primarily for cooking. The wood is also traditionally used for smoking fish and meat, though this usage has often been replaced by other woods such as oak and hickory. An exception is the smoked Pacific salmon industry in the Pacific Northwest, where alder smoking is essentially universal. This is partly due to indigenous traditions of food preservation in the area, and partly because oak, hickory, mesquite and other woods favored for smoking elsewhere are not locally available in any large quantities. Species used for Pacific salmon smoking are Red alder A. rubra and to a lesser extent Sitka alder A. viridis ssp. sinuata.

Alder is popular as a material for electric guitar bodies. It is used by many guitar makers, notably the Fender Guitar Company, who use it on top quality instruments such as the Stratocaster and Jaguar. Alder provides a brighter tone than other woods (such as mahogany), and as alder is not a particularly dense wood it provides a resonant, well-rounded tone with excellent sustain.

Alders are also exceptionally good windbreakers and are planted on the west coast of Scotland to shelter gardens.

Classification

The genus is divided into three subgenera:

Subgenus Alnus. Trees. Shoot buds stalked. Male and female catkins produced in autumn (fall) but staying closed over winter, pollinating in late winter or early spring. About 15-25 species, including:

• Alnus acuminata — Andean Alder. Andes Mountains, South America.
• Alnus cordata — Italian Alder. Italy.
• Alnus cremastogyne
• Alnus glutinosa — Black Alder. Europe.
• Alnus incana — Grey Alder. Eurasia.
  • Alnus oblongifolia (A. incana subsp. oblongifolia) — Arizona Alder. Southwestern North America.
  • Alnus rugosa (A. incana subsp. rugosa) — Speckled Alder. Northeastern North America.
  • Alnus tenuifolia (A. incana subsp. tenuifolia) — Thinleaf or Mountain Alder. Northwestern North America.
• Alnus japonica — Japanese Alder. Japan.
• Alnus jorullensis — Mexican Alder. Mexico, Guatemala.
• Alnus nepalensis — Nepalese Alder. Eastern Himalaya, southwest China.
• Alnus orientalis — Oriental Alder. Southern Turkey, northwest Syria, Cyprus.
• Alnus rhombifolia — White Alder. Interior western North America.
• Alnus rubra — Red Alder. West coastal North America.
• Alnus serrulata — Hazel alder, Tag Alder or Smooth alder. Eastern North America.
• Alnus subcordata — Caucasian Alder. Caucasus, Iran.

Subgenus Clethropsis. Trees or shrubs. Shoot buds stalked. Male and female catkins produced in autumn (fall) and expanding and pollinating then. Three species:

• Alnus formosana — Formosan Alder Taiwan
• Alnus maritima — Seaside Alder. East coastal North America, plus disjunct population in Oklahoma.
• Alnus nitida — Himalayan Alder. Western Himalaya.

Subgenus Alnobetula. Shrubs. Shoot buds not stalked. Male and female catkins produced in late spring (after leaves appear) and expanding and pollinating then. One to four species:

• Alnus viridis — Green Alder. Widespread:
  • Alnus viridis subsp. viridis. Eurasia.
  • Alnus viridis subsp. maximowiczii (A. maximowiczii). Japan.
  • Alnus viridis subsp. crispa (A. crispa). Northern North America.
  • Alnus viridis subsp. sinuata (A. sinuata, Sitka Alder or Slide Alder). Western North America, far northeastern Siberia.

References and external links

• Chen, Zhiduan and Li, Jianhua (2004). Phylogenetics and Biogeography of Alnus (Betulaceae) Inferred from Sequences of Nuclear Ribosomal DNA ITS Region. International Journal of Plant Sciences 165: 325–335.
• Flora Europaea: Alnus
• Flora of Bolivia: Alnus
• Flora of China: Alnus
• Flora of North America: Alnus
• Flora of Pakistan: Alnus

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