Alnus incana, thegrey alder,tag alder orspeckled alder, is aspecies of multi-stemmed, shrubby tree in the birch family, with a wide range across the cooler parts of the Northern Hemisphere. Tolerant of wetter soils, it can slowly spread with runners and is a common sight in swamps and wetlands.
Alnus incana var. tenuifolia male flowers in early spring along the Columbia River
It is a small- to medium-sized tree 15–20 metres (49–66 ft) tall with smooth grey bark even in old age, its life span being a maximum of 60 to 100 years. Theleaves are matt green, ovoid, 5–11 centimetres (2–4+1⁄4 in) long and4–8 cm (1+1⁄2–3+1⁄4 in) broad. The flowers arecatkins, appearing early in spring before the leaves emerge, the male catkins pendulous and 5–10 cm (2–4 in) long, the female catkins1.5 cm (5⁄8 in) long and one cm broad when mature in late autumn. The seeds are small,1–2 millimetres (1⁄32–3⁄32 in) long, and light brown with a narrow encircling wing. The grey alder has a shallow root system, and is marked not only by vigorous production of stump suckers, but also byroot suckers, especially in the northern parts of its range. The wood resembles that of theblack alder (Alnus glutinosa), but is somewhat paler and of little economic value.
There are four to six subspecies, some treated as separate species by some authors:
Alnus incana subsp.incana; grey alder – NorthernEurope and northwesternAsia, and central and southern Europe in mountains, mainly in the regions of theAlps,Carpathians and theCaucasus
Alnus incana subsp.hirsuta(Spach) Á. & D.Löve (=A. hirsutaSpach); Manchurian alder – In mountains ofNortheast Asia andCentral Asia
Alnus incana is a light-demanding, fast-growing tree that grows well on poorer soils. In central Europe, it is a colonist ofalluvial land alongside mountain brooks and streams, occurring at elevations up to 1,500 metres (4,900 ft). However, it does not require moist soil, and will also colonize screes and shallow stony slopes. In the northern part of its range, it is a common tree species at sea level in forests, abandoned fields and on lakeshores. Several species ofLepidoptera use grey alder as a food plant for theircaterpillars. In theboreal forest area of Canada,A. incana is often associated withblack spruce in the forest type termed black spruce–speckled alder.[7] The larvae of thealder woolly sawfly sometimes cause considerable defoliation to the grey alder.[8]
A. rugosa provides cover for wildlife, is browsed by deer and moose, and the seeds are eaten by birds.[9]
Alder is an excellent tree for coppicing[13] and pollarding. Its cut branches may be fed to browsing livestock such as cows and goats, then used for kindling, firewood, or light construction - while root systems fertilize adjacent agricultural plots via nitrogen fixation.[12]
TheZuni people use the bark of thetenuifolia subspecies to dye deerskin reddish brown.[14]
TheHo-Chunk eat the bark of therugosa subspecies when their stomachs are "sour" or upset.[15]
Its wood and bark are used in smoking meat,[16] particularly fish[17] and duck.[18]
^Little, Elbert L. (1980).The Audubon Society Field Guide to North American Trees: Eastern Region. New York: Knopf. p. 363.ISBN0-394-50760-6.
^Lee, O.; Choi, M.; Ha, S.; Lee, G.; Kim, J.; Park, G.; Lee, M.; Choi, Y.; Kim, M.; Oh, C. H. (2010). "Effect of pedunculagin investigated by non-invasive evaluation on atopic-like dermatitis in NC/Nga mice".Skin Research and Technology.16 (3):371–377.doi:10.1111/j.1600-0846.2010.00443.x.PMID20637007.S2CID25752299.
