Alnus rubra - Wikipedia

Alnus rubra – Wikipedia

Alnus rubra, the pink alder,[3][4]
is a deciduous broadleaf tree native to western North America (Alaska, Yukon, British Columbia, Washington, Oregon, California, Idaho and Montana).[2][5][6]


Pink alder is the biggest species of alder in North America and one of many largest on the planet, reaching heights of 20 to 30 m (66 to 98 ft). The official tallest pink alder (1979) stands 32 m (105 ft) tall in Clatsop County, Oregon (US). The identify derives from the brilliant rusty pink shade that develops in bruised or scraped bark. The bark is mottled, ashy-gray and easy, typically colonized by white lichen and moss. The leaves are ovate, 7 to 15 centimetres (2.Eight to five.9 in) lengthy, with bluntly serrated edges and a definite level on the finish; the leaf margin is revolute, the very edge being curled beneath, a diagnostic character which distinguishes it from all different alders. The leaves flip yellow within the autumn earlier than falling. The male flowers are dangling reddish catkins 10 to 15 cm (3.9 to five.9 in) lengthy in early spring. Feminine flowers happen in clusters of (3) 4–6 (8). Feminine catkins are erect throughout anthesis, however in any other case pendant. They grow to be small, woody, superficially cone-like oval dry fruit 2 to three cm (0.79 to 1.18 in) lengthy. The seeds develop between the woody bracts of the ‘cones’ and are shed in late autumn and winter. Pink alder seeds have a membranous winged margin that enables long-distance dispersal.[7]


Alnus rubra grows from southeast Alaska south to central coastal California, almost at all times inside about 200 km (120 mi) of the Pacific coast, apart from an extension 600 km (370 mi) inland throughout Washington and Oregon into northernmost Montana.[5][8]


In southern Alaska, western British Columbia and the northwestern Coast Ranges of the USA, pink alder grows on cool and moist slopes; inland and on the southern finish of its vary (California) it grows principally alongside the margins of watercourses and wetlands.[9]

Generally related timber[edit]

Pink alder is related to coast Douglas-fir (Pseudotsuga menziesii subsp. menziesii), western hemlock (Tsuga heterophylla), grand fir (Abies grandis), western redcedar (Thuja plicata), and Sitka spruce (Picea sitchensis) forests.

Alongside streambanks it’s generally related to willows (Salix spp.), pink osier dogwood (Cornus stolonifera), Oregon ash (Fraxinus latifolia), and bigleaf maple (Acer macrophyllum).

In marginal habitat[edit]

To the southeast of its vary it’s changed by white alder (Alnus rhombifolia), which is a tree of comparable stature, however which differs within the leaf margins not being rolled beneath, lack of distinct lobes, and lack of membranous wings on seed margins. Within the excessive mountains it’s changed by the smaller and extra shrub-like Sitka alder (Alnus viridis subsp. sinuata), and east of the Cascade Mountains by thinleaf alder (Alnus incana subsp. tenuifolia).

As a pioneer species[edit]

In moist forest areas Alnus rubra will quickly cowl a former burn or clearcut, typically stopping the institution of conifers. It’s a prolific seed producer, however the small, wind-dispersed seeds require an open space of mineral soil to germinate, and so skid trails and different areas disturbed by logging or fireplace are preferrred seedbeds. Such areas could host a number of hundred thousand to a number of million seedlings per hectare within the first yr after panorama disturbance.[10]

Position as wildlife fodder[edit]

Twigs and buds of alder are solely truthful browse for wildlife, although deer and elk do browse the twigs in fall and twigs and buds within the winter and spring. Beaver often eat the bark, although it isn’t a most popular species. A number of finches eat alder seeds, notably widespread redpoll and pine siskin, and as do deer mice.

As soil enricher[edit]

Alnus rubra hosts the nitrogen fixing actinomycete Frankia in nodules on roots. This affiliation permits alder to develop in nitrogen-poor soils.

Damaged department exhibiting pink weathered bark

Typical leaf discoloration attributable to ozone air pollution

As dye[edit]

A russet dye will be constituted of a decoction of the bark and was utilized by Native People to dye fishing nets in order to make them much less seen underwater.

Conventional medication utilization[edit]

Native People used pink alder bark (Alnus rubra) to deal with poison oak, insect bites, and pores and skin irritations. Blackfeet Indians used an infusion constituted of the bark of pink alder to deal with lymphatic problems and tuberculosis. Current scientific research have verified that pink alder accommodates betulin and lupeol, compounds proven to be efficient in opposition to a wide range of tumors.[11]

In restoration[edit]

Alnus rubra is a vital early colonizer of disturbed forests and riparian areas primarily due to its skill to repair nitrogen within the soil. This self-fertilizing trait permits pink alder to develop quickly, and makes it efficient in overlaying disturbed and/or degraded land, equivalent to mine spoils. Alder leaves, shed within the fall, decay readily to kind a nitrogen-enriched humus. Pink alder is often used as a rotation crop to discourage the conifer root pathogen Phellinus weirii (Laminated root rot).

Alnus rubra are often planted as decorative timber and can do nicely in Swales, riparian areas, or on stream banks, in light-textured soils that drain nicely. Pink alder doesn’t thrive in heavy, moist clay soils. If planted domestically, alders ought to be planted nicely away from drainpipes, sewage pipes, and water traces, because the roots could invade and clog the traces[citation needed].

In woodworking[edit]

Alder lumber will not be thought-about to be a sturdy possibility for outside functions,[who?] however attributable to its workability and ease of ending it’s more and more used for furnishings and cabinetry. As a result of it’s softer than different well-liked hardwoods equivalent to maple, walnut and ash, traditionally alder has not been thought-about of excessive worth for timber. Nonetheless it’s now turning into one of many extra well-liked hardwood options as it’s economically priced in comparison with many different hardwoods. On this planet of musical instrument development, pink alder is valued by some electrical guitar / electrical bass builders for its balanced tonality. Alder is steadily utilized by Native People for making masks, bowls, instrument handles, and different small items.

The looks of alder lumber ranges from white by pinkish to mild brown, has a comparatively gentle texture, minimal grain, and has medium luster. It’s simply labored, glues nicely, and takes a very good end.

In fish smoking[edit]

Due to its oily smoke, A. rubra is the wooden of selection for smoking salmon.[12]

As an environmental indicator[edit]

Moreover, pink alder is commonly utilized by scientists as a biomonitoring organism to find areas vulnerable to ozone air pollution, because the leaves react to the presence of excessive ozone ranges by growing pink to brown or purple discolorations.[13]


Pink alder, western hemlock, and bigleaf maple forest

With a present stock of about 7.4 billion cubic ft, pink alder includes 60 % of the overall hardwood quantity within the Pacific Northwest, and is by far probably the most priceless hardwood in time period of variety of merchandise, industrial worth, and manufacturing employment.[14] Rising worth of alder logs, mixed with a greater understanding of the species’ ecological function, has led some land managers to tolerate and, in some circumstances, handle for alder. Since most forest land within the Northwest is managed for conifer manufacturing, nevertheless, over 80,000 hectares of timberland are sprayed with herbicides yearly in Oregon alone to regulate pink alder and different competing hardwood species.[15] Pink alder’s speedy early progress can intervene with institution of conifer plantations[16]Herbicide spraying of pink alder over giant areas of coastal Oregon and Washington has resulted in a variety of lawsuits claiming this spraying has brought on well being issues, together with delivery defects and different human well being results.

Along with including soil nitrogen, rotations of pink alder are used to cut back laminated root rot (Phellinus weirii) in Douglas-fir forests. Nurse stands of pink alder might also cut back spruce weevil injury in Sitka spruce stands on the Olympic Peninsula [17] Alder continues to draw curiosity as log values method and infrequently exceed these of Douglas-fir.[18] This curiosity is proscribed by pink alder’s complete stand productiveness, which is considerably decrease than that of Douglas-fir and western hemlock.



  1. ^ Stritch, L. (2014). “Alnus rubra“. The IUCN Pink Checklist of Threatened Species. IUCN. 208. e.T194598A2351803. doi:10.2305/IUCN.UK.2014-3.RLTS.T194598A2351803.en.
  2. ^ a b Kew World Guidelines of Chosen Plant Households
  3. ^ USDA Crops Profile: Alnus rubra
  4. ^ “BSBI Checklist 2007”. Botanical Society of Britain and Eire. Archived from the unique (xls) on 2014-10-23. Retrieved 2014-10-17.
  5. ^ a b Biota of North America Program, 2013 county distribution map
  6. ^ Alnus rubra“. Crops of British Columbia. Vancouver, BC: College of British Columbia.
  7. ^ Furlow, J. (1979). The systematics of the American species of Alnus. Rhodora, v81-825: 1-248.
  8. ^ Alnus rubra“. Flora of North America.
  9. ^ Alnus rubra“. Jepson Flora. Berkeley, CA: College of California.
  10. ^ Zavitkovski, J.; Stevens, R.D. (1972). “Major productiveness of pink alder ecosystems”. Ecology. 53 (2): 235–242. doi:10.2307/1934076. JSTOR 1934076.
  11. ^ Tilford, Gregory L. (15 June 1997). Edible and Medicinal Crops of the West (1st ed.). Mountain Press. ISBN 0-87842-359-1.
  12. ^ Ewing, Susan (1996). The Nice Alaska Nature Factbook. Portland, OR: Alaska Northwest Books.
  13. ^ Jeannie Allen (2003-08-22). “Watching Our Ozone Climate”. NASA Earth Observatory. Archived from the unique on 2008-10-20. Retrieved 2008-10-11.
  14. ^ Hibbs, D.E.; DeBell, D.S.; Tarrant, R.F. (1995). The Biology and Administration of Pink Alder. Corvallis, OR: Oregon State College Press.
  15. ^ Oregon Dept of Forestry 2014[full citation needed]
  16. ^ Haeussler, S.T.J. (1995). “Germination, survival and early progress of pink alder seedlings within the central Coast Vary of Oregon”. Canadian Journal of Forest Analysis. 25 (10): 1639–1651. doi:10.1139/x95-178.
  17. ^ Almond, Lyle. “The worth of pink alder as an built-in pest administration instrument for controlling weevil injury to sitka spruce” (PDF). In Deal, R.L.; Harrington, C.A. 2006 (eds.). Pink Alder: A State of Information. Pacific Northwest Analysis Station (Report). Portland, OR: U.S. Division of Agriculture. Common Technical Report PNW-GTR-669 – through Division of Forestry, Province of British Columbia, Canada.
  18. ^ Bluhm, Andrew A. (25 March 2017) [31 July 2010]. Pink alder administration: Silviculture to advertising (PDF) (Report). Tree Faculty. Oregon Metropolis, OR. Archived from the unique (PDF) on 2017-12-07. Retrieved 2017-12-07 – through Oregon State College Agricultural Extension Service.

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