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: Water Birch

General Information

Betula occidentalis is a large, spreading, deciduous shrub that can grow 4 - 6 metres tall, sometimes becoming a small tree up to 10 metres tall[, ].
The tree has a wide range of traditional uses for food, medicine and as a source of materials. Very ornamental, it is sometimes grown in gardens.
Betula occidentalis is a very common species throughout a very large geographic range. 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

North, west and central N. America - Alaska to Ontario, south to California and New Mexico

Habitat

Montane stream banks, slopes, and ridges, also in moist open woods, at edges of marshes, along lakeshores, and in wet swales; at elevations from 100 - 3,000 metres[]. It is also occasionally found in drier sites[, ].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	9.00 m
Growth Rate	Fast
Pollinators	Wind
Cultivation Status	Ornamental, Wild

Cultivation Details

Succeeds in a well-drained loamy soil in a sunny position[, ]. Tolerates most soils including poor soils and heavy clays[]. Fairly wind tolerant[].
A fast-growing but short-lived tree[].
A very ornamental plant[], it hybridizes freely with several other members of this genus[]. It hybridizes in the wild with Betula papyrifera[].
A good plant to grow near the compost heap, aiding the fermentation process[].
Species in this genus are notably susceptible to honey fungus[].

Edible Uses

Young leaves and catkins - raw[].

The buds and twigs are used as a flavouring in stews[].

Inner bark - raw or cooked. Best in the spring[]. Inner bark can be dried, ground into a meal and used as a thickener in soups, or be added to flour when making bread, biscuits etc. 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[]. The sap can be used as a refreshing drink or beer, it can also be concentrated into a syrup by boiling off much of the water[]. Harvested in spring, the flow is best on a sunny day following a frost. 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.'[].

Medicinal

The bark is antirheumatic, astringent, lithontripic, salve and sedative[].

A decoction of the flowers and leaves has been used as an abortifacient[].

Agroforestry Uses:

This species is used in forested riparian buffers to help reduce steam bank erosion, protect aquatic environments, enhance wildlife and increase biodiversity[].

Other Uses

An infusion of the plant is used as a hair conditioner and dandruff treatment[].

The thin outer bark is waterproof and has been used as the cladding on canoes and dwellings, and also to make containers such as bags and drinking vessels[, ].

A brown dye is obtained from the inner bark[].

The wood is close-grained, light in weight, soft but strong[]. Trees do not grow large enough to be of use for lumber, but the wood is used locally for fence posts[]. Traditionally, the wood has been used to make paddles, snowshoes and axehandles[].
The wood makes a good fuel[, ]
The bark can be used as a kindling[].

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[, , , ].