Alnus glutinosa 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Fagales Betulaceae

Scientific Name: Alnus glutinosa (L.) Gaertn.
Infra-specific Taxa Assessed:
Regional Assessments:
Common Name(s):
English Common Alder, Black alder, European Alder
Alnus alnus Britton
Alnus vulgaris Hill
Betula alnus var. glutinosa Gaertn
Betula glutinosa Lam
Taxonomic Source(s): The Plant List. 2017. The Plant List. Version 1.1. Available at:
Taxonomic Notes: Alnus glutinosa has been called A . vulgaris Hill in some older literature; that name was not validly published (Flora of North America)

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2014
Date Assessed: 2014-08-01
Assessor(s): Shaw, K., Roy , S. & Wilson, B.
Reviewer(s): Oldfield, S. & Rivers, M.C.
This species has a wide distribution across Europe and into North Africa. Although population size has not been quantified, it is not believed to approach threshold values for a threatened category. Due to the scattered nature of subpopulations, potential future threats exist, but these are not considered significant at present. The species is therefore evaluated as Least Concern. The species was previously categorised as Least Concern by participants of the IUCN SSC Central Asian regional tree red listing workshop, held in Bishkek, Kyrgyzstan (11-13 July 2006) and published as Least Concern on the IUCN Red List in 2007. This species is listed as Least Concern in the national Red Lists of Denmark, Estonia, Norway, Luxembourg, Switzerland and Great Britain. The category remains unchanged.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species has a wide but scattered distribution, throughout the whole of Europe, Russia including Siberia, and western Asia up to 65 degrees North, and south as far as North Africa. Its densest distribution is found in the lowlands of northern Germany, northern Poland, White Russia and the northwestern Ukraine. Alnus glutinosa usually grows between zero and 1,000 m asl but in the Alps this species has been known to grow up to 1,300 m asl. It was introduced to eastern North America in colonial times and has escaped from cultivation and now grows naturally on low lying lands of northeastern United States and maritime Canada. The duration of low winter temperature limits the range of this species in Scandinavia because the species does not extend into regions where the mean daily temperature is above freezing for less than six months of the year. The southeastern boundary of this species distribution in Eurasia corresponds closely with the 500 mm annual rainfall line.
Countries occurrence:
Albania; Algeria; Austria; Belarus; Belgium; Bosnia and Herzegovina; Bulgaria; Croatia; Czech Republic; Denmark; Estonia; Finland; France (Corsica, France (mainland)); Georgia; Germany; Greece (Greece (mainland)); Hungary; Italy (Italy (mainland), Sardegna, Sicilia); Kazakhstan; Latvia; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Montenegro; Morocco; Netherlands; Norway; Poland; Portugal (Portugal (mainland)); Romania; Russian Federation (Central European Russia, Chechnya, Dagestan, Eastern Asian Russia, East European Russia, European Russia, Ingushetiya, Kabardino-Balkariya, Kaliningrad, Karachaevo-Cherkessiya, Krasnodar, North European Russia, Northwest European Russia, Severo-Osetiya, South European Russia, Stavropol, West Siberia); Serbia; Slovakia; Slovenia; Spain (Spain (mainland)); Sweden; Switzerland; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe); Ukraine (Krym, Ukraine (main part)); United Kingdom (Great Britain, Northern Ireland)
Canada; United States
Additional data:
Upper elevation limit (metres):1300
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Across its range, A. glutinosa occurs in small isolated subpopulations which has led to extensive genetic diversity. Although population size has not been quantified it is not believed to approach the thresholds for it to be considered threatened.
Current Population Trend:Stable
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:A large deciduous tree growing to a height of 20-30 m, this species favours a moderate to cold climate and prefers damp or wet soils. It grows well in acidic soils and its growth is reduced under the alkaline or near-neutral conditions that are desirable for many other species. This species is commonly found in hilly regions, along the banks of streams and rivers, in damp marshy woods and riverside woodlands. It grows alongside spring-lines in oak woods and damp hollows or on wet slopes in high rainfall areas, away from the waterside. This species can also grow on poor quality soil due to nodules on the roots with nutrifying bacteria. The roots of this species can grow into open water as dense masses of hard, dark red cords which adds support to the banks. It can rapidly seed into open sites, producing even-aged stands of mature trees, but seedlings are very shade and drought sensitive, so regeneration in woodland is often poor. This species does not tolerate temperatures of below zero for more than six months of the year and prefers areas with annual rainfall in excess of 500 mm.

Use and Trade [top]

Use and Trade: This species has multiple uses in silviculture and the wood industry. It is used for coppicing, hedging, and historically for lock gates, mill wheels and troughs as it can withstand constant wetting and drying out. In Europe it has served for many centuries as an important source of hardwood for timbers and carved items, including wooden shoes. The wood has been called the Scottish Mahogany; it is resistant to rotting. The wood also makes good charcoal. The leaves and bark were historically used to make dyes. It also plays an important role in rural superstition, being used to keep pests from fields during the sowing season. The bark and leaves of the tree also have medicinal uses, the bark is astringent, and a decoction was used as a gargle for sore throats, and the leaves were used as a poultice for swelling and inflammation. Alnus glutinosa is cultivated as an ornamental tree throughout eastern North America and the Azores and is available in a variety of cultivars. It has escaped from cultivation and become widely naturalized throughout the temperate northeast. This plant may become weedy or invasive in some regions or habitats and may displace desirable vegetation if not properly managed. Alnus glutinosa is valuable for wildlife as the cones open gradually and release seed throughout the winter, they are a dependable source of food for seed-eating birds such as pine siskins and goldfinches. It is recommended species for use in shelterbelts to provide cover for pheasants. When combined with Prunus laurocerasus and Sorbus aria it makes a compact planting suitable for establishment adjacent to cropland. This species has also been used extensively to control erosion and improve the soil on recently cleared or unstable substrates, such as sand dunes and mine spoils. Its roots break up wet compacted soil where free oxygen is limited and with a bacteria-like organism on the roots it can convert atmospheric nitrogen into a usable form.

Threats [top]

Major Threat(s): Subpopulations are scattered which has resulted in high genetic variation between subpopulations and high specificity to local conditions. If habitat loss occurs, this will result in a narrowing of the gene pool and replanting efforts may be challenged by limited ability to survive outside of specific conditions. Adaptation to specific local conditions could also present a threat in future as climate change alters local conditions. This does not present a significant threat at the moment, but could present a greater threat in the future.

A recently evolved fungus, Phytophthora alni, has killed 10% of trees in south England and Wales, and may have a wider impact in the future.

Conservation Actions [top]

Conservation Actions: Due to the genetic differentiation between subpopulations, it is important to protect the existing diversity of natural subpopulations. The species was previously categorised as Least Concern by participants of the IUCN SSC Central Asian regional tree red listing workshop, held in Bishkek, Kyrgyzstan (11-13 July 2006) and published as Least Concern on the IUCN Red List in 2007. This species is listed as Least Concern in the National Red Lists of Denmark, Estonia, Norway, Luxembourg, Switzerland and Great Britain.

Citation: Shaw, K., Roy , S. & Wilson, B. 2014. Alnus glutinosa. The IUCN Red List of Threatened Species 2014: e.T63517A3125479. . Downloaded on 22 May 2018.
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