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Alder

From Wikipedia, the free encyclopedia
(Redirected fromAlnus)
For other uses, seeAlder (disambiguation).
Not to be confused with the unrelated plantswitch alder,dwarf alder,andelder.

Alder
Temporal range:Paleocene–Recent
Common alder (Alnus glutinosa)
Scientific classificationEdit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fagales
Family: Betulaceae
Subfamily: Betuloideae
Genus: Alnus
Mill.
Type species
Alnus glutinosa
(L.) Gaertn.
Synonyms[1]
Genus synonyms
  • Betula-alnusMarshall
  • DuschekiaOpiz
  • AlnasterSpach
  • ClethropsisSpach
  • SemidopsisZumagl.
  • Alnobetula(W.D.J.Koch) Schur.
  • Cremastogyne(H.J.P.Winkl.) Czerep.
Female alder catkins after shedding their seeds
Alnus serrulatamale catkins

Aldersaretreesthat compose the genusAlnusin the birch familyBetulaceae.The genus includes about 35 species[2]ofmonoecioustrees andshrubs,a few reaching a large size, distributed throughout thenorth temperate zonewith a few species extending intoCentral America,as well as the northern and southernAndes.[1]

Description

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Pollen

With a few exceptions, alders aredeciduous,and the leaves are alternate, simple, andserrated.Theflowersarecatkinswith elongate male catkins on the same plant as shorter female catkins, often before leaves appear; they are mainlywind-pollinated,but also visited by bees to a small extent. These trees differ from thebirches(Betula,another 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 manyconifer cones.

The largest species arered alder(A. rubra) on the west coast of North America, andblack alder(A. glutinosa),nativeto most of Europe and widely introduced elsewhere, both reaching over 30 metres (100 ft). By contrast, the widespreadAlnus alnobetula(green alder) is rarely more than a 5 m-tall (16 ft) shrub.

Phylogeny

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Classification

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A young bull moosebrowsingon Alnus inHomer, Alaskain 2010
The same spot from the same angle in 2021, the plants are now about 3.7–4.6 metres (12–15 ft) in height

The genus is divided into three subgenera:

SubgenusAlnus

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Speckled alder (Alnus incanasubsp.rugosa)—leaves
Leaves of the tag alder

Trees with stalked shoot buds, male and female catkins produced in autumn (fall) but stay closed over winter, pollinating in late winter or early spring, about 15–25 species, including:

SubgenusClethropsis

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Trees or shrubs with stalked shoot buds, male and female catkins produced in autumn (fall) and expanding and pollinating then, three species:

SubgenusAlnobetula

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Green alder (Alnus viridis)

Shrubs with shoot buds not stalked, male and female catkins produced in late spring (after leaves appear) and expanding and pollinating then, one to four species:

Not assigned to a subgenus

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Species names with uncertain taxonomic status

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The status of the following species is unresolved:[citation needed]

  • Alnus balatonialisBorbás
  • Alnus cuneataGeyer ex Walp.
  • Alnus dimitroviiJordanov & Kitanov
  • Alnus djavanshiriiH.Zare– Iran
  • Alnus dolichocarpaH.Zare, Amini & Assadi– Iran
  • Alnus figertiCallier
  • Alnus frangulaL. ex Huth
  • Alnus giganteaNakai
  • Alnus glandulosaSarg.
  • Alnus henedaeSugim.
  • Alnus hybridaRchb.
  • Alnus laciniataEhrh.
  • Alnus lobataNyman
  • Alnus microphyllaArv.-Touv.
  • Alnus obtusifoliaMert. ex Regel
  • Alnus oxyacanthaLavalle
  • Alnus subrotundaDesf.
  • Alnus vilmorianaLebas
  • Alnus washingtoniaWetzel

Hybrids

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Alnus × spaethii

The following hybrids have been described:[4][5]

The status of the following hybrids is unresolved:[4]

  • Alnus×aschersonianaCallier
  • Alnus×koehneiCallier
  • Alnus×ljungeriMurai
  • Alnus×purpusiiCallier
  • Alnus×silesiacaFiek
  • Alnus×spaethiiCallier(A. japonica×A. subcordata)

Fossil record

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The oldest fossil pollen that can be identified asAlnusis from northernBohemia,dating to the latePaleocene,around 58 million years ago.[6]

Etymology

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The common namealderevolved from the Old English wordalor,which in turn is derived fromProto-Germanicrootaliso.[10]The generic nameAlnusis the equivalentLatinname, from whence Frenchaulneand SpanishAlamo(Spanish term for "poplar").[10]

Ecology

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Alders are commonly found near streams, rivers, and wetlands. Sometimes where the prevalence of alders is particularly prominent these are calledalder carrs.In thePacific Northwestof North America, thewhite alder(Alnus rhombifolia) unlike other northwest alders, has an affinity for warm, dry climates, where it grows along watercourses, such as along the lowerColumbia Rivereast of the Cascades and the Snake River, including Hells Canyon.

Alder leaves and sometimes catkins are used as food by numerous butterflies and moths.

A. glutinosaandA. viridisare classed as environmental weeds in New Zealand.[11]Alder leaves and especially the roots are important to the ecosystem because theyenrich the soil with nitrogenand other nutrients.

Nitrogen fixation and succession of woodland species

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A red alder seed is a tinysamaralike those of all alders

Alder is particularly noted for its importantsymbioticrelationship withFrankia alni,anactinomycete,filamentous,nitrogen-fi xingbacterium.This bacterium is found inroot nodules,which may be as large as a human fist, with many small lobes, and light brown in colour. The bacterium absorbsnitrogenfrom the air and makes it available to the tree. Alder, in turn, provides the bacterium withsugars,which it produces throughphotosynthesis.As a result of this mutually beneficial relationship, alder improves thefertility of the soilwhere it grows, and as apioneer species,it helps provide additional nitrogen for thesuccessionalspecies to follow.

Because of its abundance, red alder delivers large amounts of nitrogen to enrich forest soils. Red alder stands have been found to supply between 130 and 320 kilograms per hectare (120 and 290 pounds per acre) of nitrogen annually to the soil. From Alaska to Oregon,Alnus viridissubsp.sinuata(A. sinuata,Sitka Alder or Slide Alder), characteristically pioneer fresh, gravelly sites at the foot of retreating glaciers. Studies show that Sitka alder, a more shrubby variety of alder, adds nitrogen to the soil at an average rate of 60 kg/ha (54 lb/acre) per year, helping convert the sterile glacial terrain to soil capable of supporting a conifer forest. Alders are common among the first species to colonize disturbed areas from floods, windstorms, fires, landslides, etc. Alder groves often serve as natural firebreaks since these broad-leaved trees are much less flammable than conifers. Their foliage andleaf litterdoes not carry a fire well, and their thin bark is sufficiently resistant to protect them from light surface fires. In addition, the light weight of alder seeds – numbering 1.5 million per kilogram or 680,000 per pound – allows for easy dispersal by the wind. Although it outgrowscoastal Douglas-firfor the first 25 years, it is veryshade intolerantand seldom lives more than 100 years. Red alder is the Pacific Northwest's largest alder and the most plentiful and commercially important broad-leaved tree in the coastal Northwest. Groves of red alder 25 to 50 centimetres (10 to 20 in) in diameter intermingle with young Douglas-fir forests west of the Cascades, attaining a maximum height of 30 to 33 m (100 to 110 ft) in about sixty years and then are afflicted byheart rot.Alders largely help create conditions favorable for giant conifers that replace them.[2]

  • Alder root nodules
  • An alder root nodule
    Whole root nodule
  • A sectioned alder root nodule
    Sectioned root nodules

Parasites

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Alder roots are parasitized bynorthern groundcone.

Uses

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Alder coat of arms ofGrossarl,Austria

The catkins of some alder species have a degree of edibility,[12]and may be rich in protein. Reported to have a bitter and unpleasant taste, they are more useful for survival purposes. The wood of certain alder species is often used to smoke various food items such ascoffee,salmon,and other seafood.

Alder is notably stable when immersed, and has been used for millennia as a material for pilings for piers and wharves. Most of thepilingsthat form the foundation ofVenicewere made from alder trees.[13]

Alder bark contains the anti-inflammatorysalicin,which is metabolized intosalicylic acidin the body.[14]Some Native American cultures use red alder bark (Alnus rubra) to treat poison oak, insect bites, and skin irritations. Blackfeet Indians have traditionally used an infusion made from the bark of red alder to treat lymphatic disorders andtuberculosis.Recent clinical studies have verified that red alder containsbetulinandlupeol,compounds shown to be effective against a variety of tumors.[15]

The inner bark of the alder, as well asred osier dogwood,orchokecherry,is used by someIndigenous peoples of the Americasin smoking mixtures, known askinnikinnick,to improve the taste of thebearberryleaf.[16]

Alder is illustrated in the coat of arms for the Austrian town ofGrossarl.

Electric guitars, most notably those manufactured by theFender Musical Instruments Corporation,have been built with alder bodies since the 1950s. Alder is appreciated for its tone that is claimed to be tight and evenly balanced, especially when compared to mahogany, and has been adopted by many electric guitar manufacturers. It usually is finished in opaque lacquer (nitrocellulose,polyurethane,orpolyester), as it does not have a prominent grain.

As ahardwood,alder is used in making furniture, cabinets, and other woodworking products. In these applications, its aforementioned lack of prominent grain means that it is oftenveneered,either by stained light woods such as oak, ash, or figured maple, or by darker woods such as teak or walnut.

Alder bark and wood (likeoakandsweet chestnut) containtanninand are traditionally used to tan leather.

A red dye can also be extracted from the outer bark, and a yellow dye from the inner bark.[17]

Culture

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Ermanno Olmi's movieThe Tree of Wooden Clogs(L' Albero Degli Zoccoli,1978) refers in its title to alder, typically used to make clogs as in this movie's plot.[18][19]

References

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  1. ^ab"World Checklist of Selected Plant Families: Royal Botanic Gardens, Kew".apps.kew.org.
  2. ^abArno, Stephen F.; Hammerly, Ramona P. (2020) [1977].Northwest Trees: Identifying & Understanding the Region's Native Trees(field guide ed.). Seattle:Mountaineers Books.pp. 208–215.ISBN978-1-68051-329-5.OCLC1141235469.
  3. ^abVít, Petr; Douda, Jan; Krak, Karol; Havrdová, Alena; Mandák, Bohumil (2017). "Two new polyploid species closely related toAlnus glutinosain Europe and North Africa – an analysis based on morphometry, karyology, flow cytometry and microsatellites ".Taxon.66(3): 567–583.doi:10.12705/663.4.
  4. ^ab"The Plant List entry forAlnus".The Plant List,v.1.1.Royal Botanic Gardens, Kewand theMissouri Botanical Garden.September 2013.Retrieved14 December2020.
  5. ^Govaerts R."AlnusMill ".Plants of the World Online.Board of Trustees of the Royal Botanic Gardens, Kew.Retrieved14 December2020.
  6. ^Yang, Xiao-Yue; Wang, Ze-Fu; Luo, Wen-Chun; Guo, Xin-Yi; Zhang, Cai-Hua; Liu, Jian-Quan; Ren, Guang-Peng (September 2019)."Plastomes of Betulaceae and phylogenetic implications".Journal of Systematics and Evolution.57(5): 508–518.doi:10.1111/jse.12479.ISSN1674-4918.S2CID91509152.
  7. ^abcWolfe, J.A. (1966). Tertiary plants from the Cook Inlet region, Alaska (Report). Professional Paper. Vol. 398B. United States Geological Survey. pp. 1–32.doi:10.3133/pp398B.
  8. ^Chaney, R.; Axelrod, D. (1959).Miocene Floras of the Columbia Plateau: Part II. Systematic Considerations, by Ralph W. Chaney and Daniel I. Axelrod.Carnegie Institution of Washington. pp. 1–226.Miocene Floras of the Columbia Plateauat theHathiTrust Digital Library
  9. ^Wolfe, J. A.; Wehr, W. C. (1987). Middle Eocene dicotyledonous plants from Republic, northeastern Washington (Report). Bulletin. Vol. 1597. United States Geological Survey. pp. 1–25.doi:10.3133/b1597.
  10. ^abHarper, Douglas."alder | Etymology, origin and meaning of alder by etymonline".Online Etymology Dictionary.Retrieved22 March2022.
  11. ^Clayson, Howell (May 2008).Consolidated list of environmental weeds in New Zealand.Wellington: Department of Conservation.ISBN978-0-478-14412-3.
  12. ^"Plant Search Result, see e.g. Alnus rubra".pfaf.org.Retrieved17 November2020.
  13. ^Nakasako, Eric."A Look at Venice: Past and Present".Illumin.University of Southern California.Retrieved22 January2018.
  14. ^Ewing, Susan (2012).The Great Alaska Nature Factbook: A Guide to the State's Remarkable Animals, Plants, and Natural Features(2nd ed.). Graphic Arts Books. pp. 106, 142.ISBN978-0-88240-868-2.
  15. ^Tilford, Gregory L. (1997).Edible and Medicinal Plants of the West.Mountain Press.ISBN0-87842-359-1.
  16. ^Staff (2009)."Bearberry".Discovering Lewis and Clark.The Lewis and Clark Fort Mandan Foundation. Archived fromthe originalon 18 December 2010.Retrieved29 April2011.
  17. ^"Native Plant Dyes".United States Department of Agriculture Forest Service.Retrieved17 December2014.
  18. ^PRESSO LA RIVA: L'ONTANO(tr. AT THE SHORE: THE ALDER), December 2015officinadellambiente,accessed 17 November 2020
  19. ^Ontano nero(tr. Black Alder) accessed 17 November 2020uomoenatura.it

Further reading

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Wikimedia Commons has media related toAlnus.
Wikispecieshas information related toAlnus.
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