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Species
Frangula alnus P. Mill.
IUCN
NCBI
EOL Text
Forest margins, riverbanks, lakesides. N Xinjiang (Manas) [Russia; N Africa, SW Asia, Europe].
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More info for the term: fen
Birds, Henry's elfin butterflies, and small mammals feed on glossy buckthorn. A number of bird species feed on glossy buckthorn fruits and are important in seed dispersal [31,64,92]. In southern Ontario, American robins, Bohemeian waxwings, cedar waxwings, rose-breasted grosbeaks, and European starlings were observed eating glossy buckthorn fruits (Darbyshire others, personal communications in [5]). The laxative effect of fruits may, however, limit their nutritional value [34].
Studies in the Wicken Fen in Cambridgeshire, England, showed that mice harvested, consumed, and cached glossy buckthorn fruits or seeds [30].
In Ottawa-Carleton, Ontario, which is near the northern limit of Henry's elfin's range, glossy buckthorn provides important rearing habitat and food. As glossy buckthorn abundance has increased in this area, so have Henry's elfin populations. Populations of Henry's elfin in the area have increased 7 fold from 1980 to 1996 [4].
Foodplant / gall
larva of Contarinia rhamni causes gall of flower bud of Frangula alnus
Foodplant / gall
Eriophyes annulatus causes gall of leaf of Frangula alnus
Foodplant / saprobe
immersed, in clusters of 7-15 perithecium of Eutypella scoparia is saprobic on dead twig of Frangula alnus
Remarks: season: 6-2
Foodplant / saprobe
fruitbody of Exidia thuretiana is saprobic on dead, fallen wood of Frangula alnus
Other: minor host/prey
In Great Britain and/or Ireland:
Foodplant / saprobe
immersed, becoming erumpent conidioma of Dichomera coelomycetous anamorph of Gibberella zeae is saprobic on twig of Frangula alnus
Foodplant / saprobe
Haplosporella coelomycetous anamorph of Haplosporella francisci is saprobic on dead Frangula alnus
Foodplant / saprobe
immersed, bark slightly raised pseudothecium of Karstenula rhodostoma is saprobic on dead twig of Frangula alnus
Remarks: season: 1-4
Foodplant / parasite
amphigenous cleistothecium of Microsphaera divaricata parasitises leaf of Frangula alnus
Foodplant / saprobe
solitary or in small group apothecium of Pezicula frangulae is saprobic on dead branch of Frangula alnus
Remarks: season: 9-11
Foodplant / spot causer
epiphyllous, scattered, or gregarious towards spot centre pycnidium of Phyllosticta coelomycetous anamorph of Phyllosticta rhamni causes spots on live leaf of Frangula alnus
Remarks: season: 8
Foodplant / gall
pycnium of Puccinia coronata causes gall of leaf (petiole) of Frangula alnus
Foodplant / feeds on
pycnidium of Sphaeronaema coelomycetous anamorph of Scleroderris frangulae feeds on branch of Frangula alnus
Foodplant / gall
Trichochermes walkeri causes gall of leaf of Frangula alnus
Foodplant / gall
Trioza rhamni causes gall of leaf of Frangula alnus
Foodplant / saprobe
2-8 per stroma perithecium of Valsa auerswaldii is saprobic on dead branch of Frangula alnus
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Source | http://www.bioimages.org.uk/html/Frangula_alnus.htm |
Glossy buckthorn has been used medicinally as a laxative, purgative, and cancer treatment (others cited in [81]).
More info for the term: fuel
A sparse surface fuel layer [15] and "prolific" postfire sprouting [33,82] may limit the usefulness of fire to control glossy buckthorn. However, while the complete removal of glossy buckthorn through burning is unlikely, seedlings are easily killed [60], and a short-term reduction in stem abundance is possible [7,66]. Associated native species may benefit from the short-lived reduction in shade after fire in dense glossy buckthorn stands [81].
Reviews report that fire spread can be difficult without dry and/or windy conditions in glossy buckthorn thickets, which are typically too shady to support much groundlayer vegetation [13,15]. However, if fires are possible, some suggest that combinations of cutting and burning may be useful in controlling glossy buckthorn. Once adult plants are top-killed, growing-season fires may kill seedlings and saplings. Another fire in the next growing season may be necessary to remove seedlings germinating from the soil seed bank [87]. Solecki [82] and Heidorn [39] suggest that repeated "hot" fires set nearly every year for 5 to 6 years may provide glossy buckthorn control. However, Lampa (1984, personal communication cited in [13]) indicates that given a glossy buckthorn seed source, exposed soils on the burned area are more hospitable to establishment than unburned areas with intact vegetation. Additional information on the use of fire in conjunction with other control methods is discussed in Integrated management.
Rhamnus frangula (synonym Frangula alnus), the alder buckthorn, is a tall deciduous shrub in the family Rhamnaceae. It is native to Europe, northernmost Africa, and western Asia, from Ireland and Great Britain north to 68°N in Scandinavia, east to central Siberia and Xinjiang in western China, and south to northern Morocco, Turkey, and the Alborz and Caucasus Mountains; in the northwest of its range (Ireland, Scotland), it is rare and scattered. It is also introduced and naturalised in eastern North America.[3][4][5][6][7]
Contents
Taxonomy and naming[edit]
Alder Buckthorn was first formally described by Linnaeus in 1753 as Rhamnus frangula. It was subsequently separated by Philip Miller in 1768 into the genus Frangula on the basis of its hermaphrodite flowers with a five-parted corolla (dioecious, and four-parted in Rhamnus); this restored the treatment of pre-Linnaean authors, notably Tournefort.[8] Although much disputed historically, the separation of Frangula from Rhamnus is now widely accepted, being supported by recent genetic data[9] though a few authorities still retain the genus within Rhamnus (e.g. the Flora of China[7]).
The genus name Frangula refers to the brittle wood. Both the English and scientific species names refer to its commonly growing together with alders (Alnus) on damp sites. Unlike other "buckthorns", Alder Buckthorn does not have thorns.[10][11] Other recorded names include glossy buckthorn and breaking buckthorn; historically, it was sometimes called "dogwood" through confusion of the leaves with those of Dogwood Cornus sanguinea.[10]
Description[edit]
Alder Buckthorn is a deciduous shrub, growing to 3–6 m, occasionally to 7 m tall. It is usually multistemmed, but rarely forms a small tree with a trunk diameter of up to 20 cm. The bark is dark blackish-brown, with bright lemon-yellow inner bark exposed if cut. The shoots are dark brown, the winter buds without bud scales, protected only by the densely hairy outer leaves The leaves are ovate, 3–7 (–11) cm long by 2.5–4 (–6) cm wide, slightly downy on the veins, with an entire margin, 6–10 pairs of prominently grooved veins, and an 8–15 mm petiole; they are arranged alternately on the stems. The flowers are small, 3–5 mm diameter, star-shaped with five greenish-white acute triangular petals, hermaphroditic, and insect pollinated, flowering in May to June in clusters of two to ten in the leaf axils. The fruit is a small black berry 6–10 mm diameter, ripening from green through red in late summer to dark purple or black in early autumn, containing two or three pale brown 5 mm seeds. The seeds are primarily dispersed by frugivorous birds, which readily eat the fruit.[3][5][6][11][7][12]
Ecology[edit]
Alder Buckthorn grows in wet soils in open woods, scrub, hedgerows and bogs, thriving well in sunlight and moderate shade, but less vigorously in dense shade; it prefers acidic soils though will also grow on neutral soils.[6][10][12]
Rhamnus frangula is one of just two food plants (the other being Rhamnus cathartica) used by the Common Brimstone butterfly Gonepteryx rhamni. The flowers are valuable for bees, and the fruit an important food source for birds, particularly thrushes.[11]
Invasive species[edit]
Rhamnus frangula was probably introduced to North America about 200 years ago, and in Canada about 100 years ago. It was planted for hedgerows, forestry plantings, and wildlife habitat, but has become an invasive species, invading forests in the northeastern United States and wetlands and moist forest in the Midwestern United States.[13][14][15] It is predicted to continue to expand its North American range with time.[13] Its invasiveness is assisted by its high adaptability and pollution tolerance.[16]
It invades forests and grows in the understory in spots with a lot of light. These areas, usually where a tree has fallen, normally allow locally native tree seedlings to grow and eventually fill in the gap in the canopy. But when F. alnus invades and grows in these locations, its dense canopy prevents light from reaching the ground and therefore prevents other seedlings from growing.[16] It tends to grow more densely and with larger individuals in lower topographical areas with moist, fertile soils, and is very problematic for land managers. Uplands forests are not invaded as easily as lower lying ones. Hemlock-oak stands, which tend to be older stands of trees, are much less suitable for F. alnus because the density of the tree canopy creates a more shady environment that is not as suitable for F. alnus. Eastern White Pine stands are easily invaded because they allow more light to reach the forest floor, and tree stands that are cut are very quickly invaded while undisturbed stands are rarely invaded.[17]
Control[edit]
Small saplings can be hand-pulled, but control of larger examples is best achieved using herbicides.[18]F. alnus and the related species Rhamnus cathartica have been banned from sale, transport, or import to Minnesota[19] and Illinois.[20] It is considered invasive, but not banned, in Connecticut.[21]
Uses[edit]
Decorative[edit]
Alder Buckthorn has limited decorative qualities without conspicuous flowers or bold foliage, and is mainly grown for its conservation value, particularly to attract Brimstone butterflies. A variegated cultivar Rhamnus frangula 'Variegata' and a cultivar with very slender leaves 'Aslenifolia' are sometimes grown in gardens as ornamental shrubs. The cultivar 'Tallhedge' has been selected for hedging.[22]
Medicinal[edit]
Galen, a Greek physician of the 2nd century A.D., knew of Alder Buckthorn, although he did not distinguish clearly in his writings between it and other closely related species. All of these plants though, were credited with the power to protect against witchcraft, demons, poisons, and headaches.[citation needed]
The bark (and to a lesser extent the fruit) has been used as a laxative, due to its 3 - 7% anthraquinone content. Bark for medicinal use is dried and stored for a year before use, as fresh bark is violently purgative; even dried bark can be dangerous if taken in excess.[3][22]
Charcoal[edit]
Alder Buckthorn charcoal is prized in the manufacture of gunpowder, being regarded as the best wood for the purpose. It is particularly highly valued for time fuses because of its very even burn rate.[3][10] The wood was formerly used for shoe lasts, nails, and veneer. The bark yields a yellow dye, and the unripe berries furnish a green dye.[22]
References[edit]
Wikimedia Commons has media related to Rhamnus frangula. |
- ^ "The International Plant Names Index". Retrieved 3 March 2013.
|chapter=
ignored (help) - ^ "The Plant List: A Working list of All Plant Species".
- ^ a b c d Rushforth, K. (1999). Trees of Britain and Europe. Collins ISBN 0-00-220013-9.
- ^ Flora Europaea: Frangula alnus
- ^ a b Den virtuella floran: Frangula alnus (in Swedish, with detailed maps)
- ^ a b c Stace, C., et al. Interactive Flora of NW Europe: Frangula alnus
- ^ a b c Flora of China: Rhamnus frangula
- ^ Miller, P. (1754). The Gardener's Dictionary, 8th ed. Facsimile at Botanicus.org
- ^ Bolmgren, K., & Oxelman, B. 2004. Generic limits in Rhamnus L. s.l. (Rhamnaceae) inferred from nuclear and chloroplast DNA sequence phylogenies. Taxon 53: 383–390.
- ^ a b c d Vedel, H., & Lange, J. (1960). Trees and Bushes in Wood and Hedgerow. Methuen & Co Ltd.
- ^ a b c Natural England: Alder buckthorn
- ^ a b Blamey, M. & Grey-Wilson, C. (1989). Flora of Britain and Northern Europe. ISBN 0-340-40170-2.
- ^ a b Wingard, Hanna S. "Invasion of transition hardwood forests by exotic Rhamnus frangula: Chronology and site requirements". University of New Hampshire, 2007.
- ^ "Common Buckthorn and Glossy Buckthorn". University of Maine Cooperative Extension Bulletin #2505.
- ^ "glossy buckthorn". Invasive.org: Center for Invasive Species and Ecosystem Health.
- ^ a b "Guide to invasive upland plant species in New Hampshire". New Hampshire Department of Agriculture, Markets & Food Terrestrial Invasive Plant Species, page 14.
- ^ Chelsea Cunard and Thomas D. Lee. "Is patience a virtue? Succession, light, and the death of invasive glossy buckthorn (Frangula alnus)". Biological Invasions:Volume 11, Number 3 / March, 2009.
- ^ "What you can do to control buckthorn!". MN Department of Natural Resources.
- ^ "Buckthorn". MN Department of Natural Resources.
- ^ "Reminder to Gardeners: Some Exotic Plants Banned in Illinois". Illinois DIllinois Department of Natural Resources. April 22, 2004.
- ^ "Connecticut Invasive Plant List July 2009". CT Invasive Plants Council.
- ^ a b c Plants for a Future: Rhamnus frangula
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More info for the terms: fire regime, fire-return interval, fuel, top-kill, total heat release
In its native habitat of southern Switzerland, glossy buckthorn was most frequent on sites with an average fire-return interval of up to 50 years and least frequent on sites unburned for more than 100 years [16]. While fire regimes were not explicitly described in invaded North American habitats, glossy buckthorn's ability to sprout following top-kill suggests a tolerance of short fire-return intervals. Persistence in shaded sites [12] and widely animal-dispersed seed [31,34,39,64] suggest that long fire-return intervals could be tolerated as well. In laboratory tests, glossy buckthorn produced low heat of combustion (11.45 MJ/kg) and total heat release (11.32 MJ/kg) when burned. These values were much lower than those of other associated native vegetation, suggesting that glossy buckthorn populations could possible alter properties of the native fuel bed [17]. The Fire Regime Table summarizes characteristics of FIRE REGIMES for vegetation communities in which glossy buckthorn may occur. Follow the links in the table to documents for more detailed information on these FIRE REGIMES.
The bark is used medicinally for stomach pain. The bark and young fruit contain dye. The timber is used for making charcoal and gunpowder.
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More info on this topic.
More info for the terms: basal area, density, fen, frequency, natural, shrub, succession
In its native European habitats, glossy buckthorn is described as "on the whole intolerant of shade". Glossy buckthorn is typical in the understory of open woodlands, is often abundant following logging and/or grazing, but is rare in late-seral, closed-canopy forests [31]. Based on studies and observations made in the Wicken fen of Cambridgeshire, England, glossy buckthorn was an early species in fen succession. It was one of the first to dominate the shrub stage but was later replaced by common buckthorn [30].
In the United States and Canada, glossy buckthorn is described in many early-seral nonnative habitats. Colonization of newly disturbed or abandoned sites by sprouting is nearly guaranteed if glossy buckthorn was present before the disturbance. Colonization by seed dispersed onto disturbed sites is also common. Contrary to reports from its native European habitats, reports from the United States and Canada indicate that glossy buckthorn tolerates both full sun and heavy shade [15,93], suggesting it may be less restricted to open-canopy woodlands and disturbed sites in North American habitats. In southern Ontario, glossy buckthorn occurs in old fields, shaded ravines, and dense woodlands, but may occupy only edge habitats in very dense forests [5,83].
Although possible in shady sites in North America, glossy buckthorn growth and reproduction may be reduced in low light conditions. In New England, glossy buckthorn fails to produce seed in densely shaded sites but may persist vegetatively for up to 50 years [12]. In the Mt Toby Experimental Forest, glossy buckthorn seedling survival and growth were compared in clearings and in the understory of a 14-year-old mixed-hardwood stand. Seedling survival, height, biomass, leaf area, and relative height growth were greater in clearings than in the understory [77]:
Differences in the characteristics of glossy buckthorn seedlings growing in the open and in a woodland understory [77] | |||||
Characteristic measured | Survival (%) | Height (cm) | Biomass (g) | Leaf area (cm²) | Relative height growth rates (cm/m/d) |
Open | 62a | 43.9a | 4.97a | 421a | 1.62a |
Understory | 48a | 12.5b | 0.14b | 13.7b | 0.10b |
Values within a column followed by different letters are significantly different (P=0.05). |
Glossy buckthorn is common in early-seral and recently disturbed habitats. Colonization or regeneration can be nearly immediate on disturbed sites. At the W. K. Kellogg Biological Station in southwestern Michigan, the emergence and density of glossy buckthorn stems increased with time since abandonment of an agricultural field with 3 small, adjacent forest fragments. Glossy buckthorn first appeared in the 3rd year after abandonment, and new seedlings emerged nearly every year after, through 7 years of abandonment. Density of glossy buckthorn was 0.17 plants/200 m² in the 3rd year after abandonment and 2.5 plants/200 m² in the 5th [23]. In a New England horse paddock abandoned for 10 years, a dense stand of glossy buckthorn 10 to 15 feet (3-4.6 m) tall dominated to the near exclusion of any other species [12]. In the Cedar Creek Natural History Area, glossy buckthorn was not present before a severe windstorm but had a density of 6.6 individuals/ha 11 years after the storm and 9.9 individuals/ha 14 years after the storm. Straight-line winds caused substantial mortality in the even-aged eastern white pine stand [2]. In southeastern Wisconsin, glossy buckthorn occurred with low frequency within 1 month of draining and surface mining that removed the existing vegetation and most of the seed bank [58]. After early spring or summer logging in Massachusetts, "germination of glossy buckthorn seeds (was) extraordinary, with hundreds of plants per square meter" (MacDougall, Land Manager for Essex County Greenbelt in Massachusetts, as cited in [12]). In western Massachusetts, researchers found that glossy buckthorn was positively associated with low carbon:nitrogen ratios and high-intensity harvests (>10 m² of basal area of stumps/ha) in mixed-hardwood, eastern white pine, eastern hemlock (Tsuga canadensis), and/or oak forests harvested in the last 20 years (P=0.003) [62].
Comments: Exotic in North America (Kartesz, 1999); often treated in the genus Rhamnus as Rhamnus frangula.
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