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Allen, L - European rowan

Page history last edited by PBworks 11 years, 11 months ago

 

Laura Allen

Plant topic: European Rowan or Mountain ash

Scientific/Botanical Name: Sorbus aucuparia glabrata

     I chose a subspecies of the European Rowan because I wanted to learn about a tree that is not native to America, but one whose name I have previously heard. To my untrained eye, the Rowan is pretty, but relatively normal in appearance. One interesting fact about it is that it has culturally been associated with magical properties, particularly in parts of England. I will discuss folklore about the Rowan at the end of this site.

Pictures:

This is a picture of the red berries (most common shape/color) of Sorbus aucuparia (Crellin 2007).

This is a picture of the small white flowers and leaflets of the most common subspecies of Sorbus aucuparia (Crellin 2005).

Map of the locations of Sorbus aucuparia:

This map shows the locations of several subspecies of Sorbus aucuparia in Europe and Asia (Anderberg 2000).

European Rowan (Sorbus aucuparia glabrata) is located in temperate coniferous forests, boreal forests or taiga, and in the subalpine tundra (WWF 2008).

     Sorbus aucuparia glabrata is a perennial tree reaching up to 15-20 meters of height at maturity. It is a slender tree with smooth, gray bark; its leaves are about 25cm long with thin, tapered pairs of 2-6cm long leaflets (Raspe et al. 2000). Tiny flowers occur in bundles of about 250 per bunch, and the flowers from the lowest part of the bunch are on long stems so that they are even with the ones on top (Raspe et al. 2000). Flowers are usually 5-merous, sometimes 4-merous, which means that the sepals and petals come in whirls of 5 or 4 (Raspe et al. 2000). Rowan's fruit has two to five chambers (with one to two seeds each), and the fruit type is pome (Raspe et al. 2000). Fruit color ranges within the wild forms of the species from a deep red to orange (Raspe et al. 2000).

European Rowan is a common species of tree. There are many subspecies of Sorbus aucuparia all over the world, and the European Rowan is invasive in several of the northern United States. Here is a map showing in which states it is present:

The European Rowan is present in Iowa, Illinois, Maine, Minnesota, Oregon, Washington, and Wisconsin (Swearingen 2007).

     The Rowan has been associated with having medicinal and magical powers throughout European folklore. It is said that one may ward off evil spirits by placing a sprig of Rowan over one's door, and that using Rowan in construction of one's house was thought to be a strong shield against witchcraft (Hunt, Relf 2005). It has many common names indicating its magical properties, a few of which are witchbane, witch ash, and witchwood. Making a cradle with Rowan rockers was said to promote innocence in a child, and placing Rowan garlands around the necks of pigs was thought to cause them to fatten faster (Hunt, Relf 2005).

 

European Rowan or Mountain ash

 

Sorbus aucuparia glabrata

 

By: Laura Allen

 

European Rowan (Sorbus aucuparia glabrata) is located in temperate coniferous forests, temperate broadleaf and mixed forests, boreal forests or taiga, and in the subalpine tundra (WWF 2008). The European Rowan can thrive in these very different habitats, and it is a common species of tree. It is native to northern, central, and southern Europe, northern Russia, and Iceland, but many subspecies of Sorbus aucuparia can be found all over the world, and the European Rowan is invasive in several of the northern United States (Anderberg 2000).  The European Rowan is invasive in Iowa, Illinois, Maine, Minnesota, Oregon, Washington, and Wisconsin (Swearingen 2007). 

 

Most of the tundra in which Sorbus aucuparia resides is relatively stable/intact, although some parts are vulnerable (WWF 2008).   One of the few threats to the tundra that humans pose in Russia is potential of gas and oil extraction (WWF 2008).  Other factors influencing the region are pollution due to ships and other marine travel and global warming.  The boreal forests and taiga are relatively stable/intact, and there are also vulnerable areas.  The threats are due to clear-cutting of old growth forests, mining, agriculture, pasturing, air pollution, and recreation (WWF 2008). Some of the temperate broadleaf and mixed forests are vulnerable, and some are critical/endangered due to clear-cuts, poaching, fires, pasturing, agricultural expansion, industrialization, and resource extraction (WWF 2008).  The temperate coniferous forests are vulnerable or critical/endangered due to agriculture, tourism, pollution form power plants and other industrial buildings, firewood collection, deforestation, overgrazing and soil erosion (WWF 2008).

 

Only a few of the human influences on the habitats of Sorbus aucuparia have been outlined above, but one can see that the impact of humanity on the ecosystems of the European Rowan is extensive.  The tree is very resilient and adaptable to changes in its environment, so it will probably not go extinct anytime in the near future. It's biological adaptations help it to survive by lending it flexibility to adapt to changing ecosystems. Sorbus aucuparia glabrata is a perennial tree reaching up to 15-20 meters of height at maturity. It is a slender tree with smooth, gray bark; its leaves are about 25cm long with thin, tapered pairs of 2-6cm long leaflets (Raspe et al. 2000). It’s tiny flowers occur in bundles of about 250 per bunch, and the flowers from the lowest part of the bunch are on long stems so that they are even with the ones on top (Raspe et al. 2000). The flowers are pollinated by insects, and so habitat destruction may pose a threat if its pollinators are eliminated.  Fruit color ranges within the wild forms of the species from a deep red to orange, attracting birds as seed dispersers (Raspe et al. 2000).  Many birds eat the seeds and disperse them through their dropping, and so loss of their seed dispersers could also result in a threat to Sorbus aucuparia.  But, Sorbus aucuparia’s pollinators and seed dispersers are not limited to any specific species, and so this flexibility gives it a better chance of surviving some habitat destruction.  

 

Humans have had an impact on the European Rowan for centuries.  The Rowan has been associated with having medicinal and magical powers throughout European folklore. It is said that one may ward off evil spirits by placing a sprig of Rowan over one's door, and that using Rowan in construction of one's house was thought to be a strong shield against witchcraft (Hunt, Relf 2005). It has many common names indicating its magical properties, a few of which are witchbane, witch ash, and witchwood. Making a cradle with Rowan rockers was said to promote innocence in a child, and placing Rowan garlands around the necks of pigs was thought to cause them to fatten faster (Hunt, Relf 2005). For these reasons, Rowans were grown in common or sacred gardens in England and Europe.

Because humans culturally value the Rowan for its magical and aesthetic purposes, extinction of Sorbus aucuparia is unlikely.  Measures are being taken to preserve many of the vulnerable or threatened habitats in which Sorbus aucuparia currently lives, and it will be able to repopulate those areas without human help from the largely stable/intact tundra habitats.

 

 

Bibliography

Anderberg A. Den Virtuella Floran: Sorbus L.. [homepage on the Internet].

Naturhistoriska riksmuseet; 2000 Mar. 16. [cited 2008 Feb. 18]. Available from:

http://linnaeus.nrm.se/flora/di/rosa/sorbu/.

Conservation Science - Palearctic. [homepage on the Internet]. World Wildlife Fund;

2008. [cited 2008 Feb. 18]. Available from:

http://www.worldwildlife.org/science/ecoregions/palearctic.cfm

Crellin J. Rowan (Sorbus aucuparia) [homepage on the Internet]. FloralImages; 2005

May 10. [cited 2008 Feb. 18]. Available from:

http://www.floralimages.co.uk/psorbuaucup.htm.

Crellin J. Rowan (Sorbus aucuparia) [homepage on the Internet]. FloralImages; 2007

Aug. 3. [cited 2008 Feb. 18]. Available from:

http://www.floralimages.co.uk/psorbuaucup1.htm.

Hunt, Jeremy, Relf, Tim. 2003. Devoted to rowan trees. Farmers Weekly 143(9): 3-3.

Raspe O, Finldlay C, Jacquemart A. Sorbus aucuparia L., The Journal of Ecology 2000;

88 (5): 910-930. Available from: http://links.jstor.org/sici?sici=0022-

0477%28200010%29.... Accessed  2008 Feb. 18.

Swearingen J. PCA Alien Plant Working Group [homepage on the Internet]. National

Park Service; 2007 Apr. 10. [cited 2008 Feb. 18]. Available from:

http://www.nps.gov/plants/ALIEN/list/s.htm.

 

 

 

 

 

 

 

 

 

 

 

 

 

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