Alnus rubra
| Alnus rubra | |
| Light: |   |
| Moisture: |   |
| Hardiness: | 6 |
| Soil pH: | 5.6-8.4 |
| Height: | 66' |
| Speed: | Fast |
| Blooms: | Early Spring |
| Open Woods Forest | |
| Native to: | |
| Nitrogen Fixer | |
| Edible Rating: |  |
| Medicinal Rating: |  |
| Tea: | Yes |
 | |
Alnus rubra (common name: red alder)
Propagation: Seed - best sown in a cold frame as soon as it is ripe and only just covered[1]. Spring sown seed should also germinate successfully so long as it is not covered[1][K]. The seed should germinate in the spring as the weather warms up. When large enough to handle, prick the seedlings out into individual pots. If growth is sufficient, it is possible to plant them out into their permanent positions in the summer, otherwise keep them in pots outdoors and plant them out in the spring.
If you have sufficient quantity of seed, it can be sown thinly in an outdoor seed bed in the spring[2]. The seedlings can either be planted out into their permanent positions in the autumn/winter, or they can be allowed to grow on in the seed bed for a further season before planting them.
Cuttings of mature wood, taken as soon as the leaves fall in autumn, outdoors in sandy soil.
Cultivation: Prefers a heavy soil and a damp situation[3][4]. Grows well in heavy clay soils[4]. Tolerates very infertile sites[1]. A very wind resistant tree with excellent establishment in severely exposed sites, it tolerates severe maritime exposure[5][K].
The red alder is a very fast growing tree, even when planted in severe exposure[5][6][K], but it is short-lived, dying when 60 - 80 years old[6]. Trees that are 5 years old from seed have reached 6 metres in height on a very exposed site in Cornwall, they are showing no signs of wind-shaping[K]. This is an important pioneer tree, quickly invading logged or burnt over sites, and providing ideal conditions for other trees to become established[6][K].
A very ornamental tree[3].
This species has a symbiotic relationship with certain soil micro-organisms, these form nodules on the roots of the plants and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[1]. Red alder has been estimated to fix as much as 300 kg of nitrogen per hectare[7].
Range: Western N. America - Alaska to California.
Habitat: Moist rich soils in woods, usually below 600 metres and within 50 km of the coast[8][9][6].
Edibility: Catkins - raw or cooked. They are rich in protein but have a bitter flavour and are not very palatable[10].
Inner bark - cooked, It must be dried since it is emetic when fresh[11][12][13]. No more details are given but inner bark is often dried, ground into a powder and then used as a thickening in soups etc or mixed with cereals when making bread[K].
Sap - raw[14]. Harvested in late winter, the flow is best on a warm, sunny day that follows a cold frosty night. A sweet flavour, it was often used to sweeten other foods[15].
Buds[11][13]. No further information is given, does this refer to the flower buds or leaf buds?[K]
Medicinal: Red alder was widely employed medicinally by native North American Indians who mainly used the bark to treat a wide range of complaints[15]. The plant is little used in modern herbalism[K].
The bark is appetizer, astringent, cathartic, cytostatic, emetic, stomachic and tonic[16][10][15]. The bark contains salicin[17], which probably decomposes into salicylic acid (closely related to aspirin) in the human body[18]. This is used as an anodyne and febrifuge[17]. An infusion of the bark has been used in the treatment of many complaints such as headaches, rheumatic pains, internal injuries and diarrhoea[17][15]. Externally, a poultice of the bark has been applied to eczema, sores and aches[15].
The sap is applied externally to cuts[15].
The catkins and young cones are astringent and have been chewed in the treatment of diarrhoea[15].
Usage: A fast-growing and very wind resistant tree, it is an excellent plant for providing rapidly produced shelterbelts[K]. The trees extensive root system also makes it suitable for controlling erosion along the banks of rivers[17].
This is an excellent pioneer species for re-establishing woodlands on disused farmland, difficult sites etc[17]. Its fast rate of growth means that it quickly provides sheltered conditions to allow more permanent woodland trees to become established. In addition, bacteria on the roots fix atmospheric nitrogen - whilst this enables the tree to grow well in quite poor soils it also makes some of this nitrogen available to other plants growing nearby. Alder trees also have a heavy leaf canopy and when the leaves fall in the autumn they help to build up the humus content of the soil. Alder seedlings do not compete well in shady woodland conditions and so this species gradually dies out as the other trees become established[K].
Tannin is obtained from the bark and the strobils[9].
Both the roots and the young shoots have been used in making baskets[15].
A red to brown dye is obtained from the bark[16][14][15].
Wood - soft, brittle, not strong, light, close and straight-grained, very durable in water[9]. An important lumber tree, it makes a good imitation mahogany[8][19] and is used for cheap furniture etc[20][16][9][21][6]. A good fuel, it does not spark so can be used in the open[8][14][10], it also makes a high grade charcoal[19].
Pollinators: Wind
Notes: You will not fing a better pioneer plant - within 5 years the plants will be 5 metres or more tall.
Soil: Can grow in medium and heavy soils.
Wind: Tolerates maritime wind exposure
Seed Ripens: Early Fall-Mid Fall
Flower Type: Monoecious
Heavy Clay: Grows in heavy-clay soils.
Known Hazards: The freshly harvested inner bark is emetic but is alright once it has been dried[10].
Also Known As: A. oregona.
Links
References
- ↑ 1.0 1.1 1.2 1.3 Huxley, Anthony. The New Royal Horticultural Society Dictionary of Gardening. MacMillan Press, 1992.
- ↑ Sheat, Wilfrid. Propagation of Trees, Shrubs and Conifers. St Martin, 1948.
- ↑ 3.0 3.1 Chittendon, Fred. RHS Dictionary of Plants. Oxford University Press, 1951.
- ↑ 4.0 4.1 Bean, William. Trees and Shrubs Hardy in Great Britain. Murray, 1981.
- ↑ 5.0 5.1 Rosewarne Experimental Horticultural Station. Shelter Trees and Hedges. Ministry of Agriculture, Fisheries and Food, 1984.
- ↑ 6.0 6.1 6.2 6.3 6.4 Elias, Thomas. The Complete Trees of North America. Van Nostrand Reinhold, 1980.
- ↑ Duke, James. Handbook of Energy Crops. 1983.
- ↑ 8.0 8.1 8.2 Hitchcock, Leo. Vascular Plants of the Pacific Northwest. University of Washington Press, 1955.
- ↑ 9.0 9.1 9.2 9.3 Sargent, Charles. Manual of the Trees of North America. Dover, 1965.
- ↑ 10.0 10.1 10.2 10.3 Schofield, Janice. Discovering Wild Plants.
- ↑ 11.0 11.1 Tanaka, Tyōzaburō. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing, 1976.
- ↑ Yanovsky, Elias. Food Plants of the North American Indians Publication 237. US Department of Agriculture.
- ↑ 13.0 13.1 Kunkel, Günther. Plants for Human Consumption. Koeltz Scientific Books, 1984.
- ↑ 14.0 14.1 14.2 Gunther, Erna. Ethnobotany of Western Washington. University of Washington Press, 1981.
- ↑ 15.0 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 Moerman, Daniel. Native American Ethnobotany. Timber Press, 1998.
- ↑ 16.0 16.1 16.2 Usher, George. A Dictionary of Plants Used by Man. Constable, 1974.
- ↑ 17.0 17.1 17.2 17.3 17.4 Lauriault, Jean. Identification Guide to the Trees of Canada. Fitzhenry and Whiteside, 1989.
- ↑ Weiner, Michael. Earth Medicine, Earth Food. Ballantine Books, 1980.
- ↑ 19.0 19.1 Heywood, Vernon. Flowering Plants of the World. Oxford University Press.
- ↑ Uphof, Johannes. Dictionary of Economic Plants. Weinheim, 1959.
- ↑ Hill, Albert. Economic Botany. The Maple Press, 1952.