Species of the genus Betula are a difficult group taxonomically because of their high vegetative variability and frequent hybridization. Many species have been founded on only slight differences and many of these have subsequently been reduced to synonymy. Many morphologic and cytologic studies have attempted to deal with variation within the genus or its subgroups. Species of Betula form a polyploid series, with chromosome numbers of 2 n = 28, , , , and 112, plus additional numbers in some hybrids.

Common Name: Yellow Birch

General Information

Betula alleghaniensis is a deciduous tree with an open, narrowly round canopy; it usually grows from 18 - 23 metres tall, though can reach 30 metres. The bole is straight and cylindrical[, ]. At higher elevations it can sometimes form sub-alpine dwarf forests[].
The tree has a wide range of traditional uses as a food, medicine and source of materials. It is an economically important timber species, with 50% of the growing stock occurring in Quebec, Canada, and is one of the most valuable woods in North America[].
This species is listed as globally secure by NatureServe. It is a widespread, commonly encountered tree of eastern North America and Canada. There are no known threats that are or will adversely affect this species in the foreseeable future. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

, ,

Range

Eastern N. America - Ontario to Newfoundland, south to Alabama and Georgia

Habitat

Usually found in moist well-drained soils in rich woodlands on lower slopes, it is also found in cool marshlands in the south of its range[, ]. Stream banks, swampy woods, and rich, moist, forested slopes; at elevations to 500 metres[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	20.00 m
Growth Rate	Slow
Pollinators	Wind
Cultivation Status	Wild

Cultivation Details

Betula alleghaniensis at its northern geographic limit coincides with an average annual temperature of 2°c isotherm and at its southern and western geographic limits coincides with an average annual temperature of 36°c[]. Trees are generally very cold tolerant, but young trees are susceptible to late spring frosts[]. Annual precipitation ranges from about 1,270mm in the East to 640mm in central Minnesota at its western limit. More than half of the precipitation may be snow. The growing season ranges from 60 to 150 days and averages about 120 days[].
Succeeds in a well-drained loamy soil in a sheltered position[, ]. Grows well in heavy clay soils. The plant can often be abundant in soils where the drainage is impeded, though growth is usually poor in such conditions[]. Reasonably shade tolerant[]. Tolerates a pH in the range 4 - 8.0[].
A slow-growing tree, it is relatively long-lived for a birch, usually around 150 years but with specimens over 300 years old recorded[, ].
The trees are highly susceptible to forest fires - even when wet the bark is highly inflammable[].
The bruised foliage has a strong smell of wintergreen[].
Hybridizes freely with several other members of this genus, especially Betula lenta, with which it is closely related[, ].
Species in this genus are notably susceptible to honey fungus[].

Edible Uses

Inner bark - cooked or dried and ground into a powder and used with cereals in making bread[]. Inner bark is generally only seen as a famine food, used when other forms of starch are not available or are in short supply[].

Sap - raw or cooked. A sweet flavour[, , , ]. The sap is harvested in early spring, before the leaves unfurl, by tapping the trunk. It flows abundantly, but the sugar content is much lower than maple sap[]. A pleasant drink, it can also be concentrated into a syrup or fermented into a beer[, ]. An old English recipe for the beer is as follows:-
'To every Gallon of Birch-water put a quart of Honey, well stirr'd together; then boil it almost an hour with a few Cloves, and a little Limon-peel, keeping it well scumm'd. When it is sufficiently boil'd, and become cold, add to it three or four Spoonfuls of good Ale to make it work...and when the Test begins to settle, bottle it up . . . It is gentle, and very harmless in operation within the body, and exceedingly sharpens the Appetite, being drunk ante pastum.'[].

A tea is made from the twigs and leaves[, ]. The dried leaves are used according to another report[]. An excellent flavour[].

The twigs and leaves have the flavour of wintergreen and can be used as condiments[].

Medicinal

Yellow birch is little used medicinally, though a decoction of the bark has been used by the native North American Indians as a blood purifier, acting to cleanse the body by its emetic and cathartic properties[].

The bark is a source of 'Oil of Wintergreen'[]. An essential oil containing methyl salicylate, it is anti-inflammatory, analgesic and rubefacient[]. It can be used in the treatment of rheumatism, bladder infections, neuralgia etc[], though it is mainly used as a flavouring in medicines[].

Agroforestry Uses:

The plant is an early colonizer of open sites and disturbed soils, often persisting as climax tree species become established. It can be used as a pioneer for restoring native woodland[].

Other Uses

The bark is waterproof and has been used by native peoples as the outer skin of canoes, as roofing material on dwellings and to make containers such as buckets, baskets and dishes[].

The wood is of high quality - it is close-grained, fine-textured, very strong, hard, heavy. The wood is too dense to float[]. An important source of hardwood lumber, it is used for furniture, cabinets, veneer, boxes, agricultural implements, tubs of wheels, floors etc[, , , , ]. It is one of the most important hardwoods in the distillation of wood alcohol and acetate of lime[].
The wood is often used as a fuel[, ]. Within its range it is a very good firewood[].

Propagation

Seed - best sown as soon as it is ripe in a light position in a cold frame[, , , ]. Only just cover the seed and place the pot in a sunny position[, , ]. Spring sown seed should be surface sown in a sunny position in a cold frame[, ]. If the germination is poor, raising the temperature by covering the seed with glass can help[]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in a cold frame for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.
If you have sufficient seed, it can be sown in an outdoor seedbed, either as soon as it is ripe or in the early spring - do not cover the spring sown seed. Grow the plants on in the seedbed for 2 years before planting them out into their permanent positions in the winter[, , , ].