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: Paper Birch

General Information

Betula papyrifera is a deciduous tree with a narrowly round, open crown; it usually grows up to 20 metres tall but sometimes reaches 30 metres. It usually has a single, straight, cylindrical bole, but sometimes has two or more[, ].
This species was an exceedingly important tree for the native North Americans - they utilized it for a very wide range of applications and it was a central item in their economy[]. It is still cultivated widely as an ornamental in temperate gardens, in particular for its attractive white bark[].
Betula papyrifera is a widespread, commonly encountered tree in Northern N. America. There are no known threats that are or will adversely affect it 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

Northern N. America - Alaska to Labrador and Newfoundland, south to Oregon and Virginia

Habitat

Woods, usually on slopes, edges of ponds, streams and swamps etc[, ]. Found in a wide range of soil conditions, but the best specimens are found in well-drained sandy-loam soils[].

Properties

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

Cultivation Details

At its northern geographic limit this species coincides with an average July temperature of 13°c isotherm and at its southern geographic limit coincides with an average July temperature of 21° c isotherm. It grows with wide variations in the patterns and amounts of annual precipitation from a low of 300mm in Alaska to 1,520mm at high elevations in the Appalachian Mountains[].
Succeeds in a well-drained loamy soil in a sunny position[, ]. Tolerates most soils including poor soils and heavy clays[]. Fairly wind tolerant[]. This species is very unhappy on our windy site in Cornwall[].
A fast-growing but short-lived species[].
It is often a pioneer species of areas ravaged by fire[]. The trunk and branches are easily killed by fire, though the tree usually regenerates from the roots[].
It hybridizes freely with other members of this genus[].
A good plant to grow near the compost heap, aiding the fermentation process[].
Betula papyrifera is the state tree of New Hampshire[].
Species in this genus are notably susceptible to honey fungus[].

Edible Uses

Inner bark - raw or cooked. Best in the spring[]. The inner bark can also be dried and ground into a meal and used as a thickener in soups or be added to flour and used in 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. A sweet flavour[]. Harvested in early spring, before the leaves unfurl, by tapping the trunk[]. The flow is best on warm sunny days following a hard frost. The sap usually runs freely, but the sugar content is lower than in the sugar maples[]. A pleasant sweet drink, it can also be concentrated into a syrup or sugar by boiling off much of the water[, ]. The sap can also be fermented to make birch beer or vinegar[]. 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.'[].

Very young leaves, shoots and catkins - raw or cooked[, ].

A tea is made from the young leaves[] and also from the root bark[].

Medicinal

Paper birch was often employed medicinally by many native North American Indian tribes who used it especially to treat skin problems[]. It is little used in modern herbalism.

The bark is antirheumatic, astringent, lithontripic, salve and sedative[]. Taken internally, the decoction has been used to treat dysentery and various diseases of the blood[].
The dried and powdered bark has been used to treat nappy rash in babies and various other skin rashes[]. A poultice of the thin outer bark has been used as a bandage on burns[]. A decoction of the inner bark has been used as a wash on rashes and other skin sores[].
The bark has been used to make casts for broken limbs. A soft material such as a cloth is placed next to the skin over the broken bone. Birch bark is then tied over the cloth and is gently heated until it shrinks to fit the limb[].

A decoction of the wood has been used to induce sweating and to ensure an adequate supply of milk in a nursing mother[].

A decoction of both the wood and the bark has been used to treat female ailments[].

Agroforestry Uses:

A pioneer species, it rapidly invades deforested areas (such as after a forest fire or logging) and creates suitable conditions for other woodland trees to follow. Because it cannot grow or reproduce very successfully in the shade it is eventually out-competed by the other woodland trees[].
The species is an important successional tree, coming up readily after fires, logging, or the abandonment of cultivated land[].
The tree has an extensive root system and can be planted to control banks from erosion[].

Other Uses

The thin layer of outer bark has a high oil content and is consequently waterproof, as well as being durable, tough and resinous[, , ].. It is used to make a wide range of products, including drinking vessels, canoe skins, roofing tiles, clothing, basketry, buckets etc[, , , , , , ]. The bark is still used in Canada today, where baskets and 'bark-biting' artwork are sold to tourists. Bark sheets are also used commercially for handicrafts and floral arrangement[, ].
Only the thin outer bark needs to be removed, this does not kill the tree[]. It is most easily removed in late spring to early summer[].

The thin outer bark can be used as a paper substitute. It is carefully peeled off the tree and used as it is[].

The outer bark has also been used as emergency sun-glasses in order to prevent snow-blindness[]. A strip of bark 4 - 5cm wide is placed over the eyes, the natural openings (lenticels) in the bark serving as apertures for the eyes[].

A brown to red dye can be made from the inner bark[].

The bark is a good tinder[].

An infusion of the leaves is used as a hair shampoo, it is effective against dandruff[, ].

A fibre is obtained from the inner bark and another from the heartwood, these are used in making paper[]. The heartwood fibre is 0.8 - 2.7mm long, that from the bark is probably longer[]. The branches of the tree can be harvested in spring or summer, the leaves and outer bark are removed, the branches are steamed and the fibres stripped off[].

The wood is light in weight, strong, tough, hard to relatively soft, very close grained, elastic, not durable. It weighs 37lb per cubic foot and is used for a variety of purposes including clothespins, spools, ice cream sticks, toothpicks, turnery, veneer, pulp etc[, , , , , , , ].
The wood is also used as a fuel[, ]. It splits easily and gives off considerable heat even when green, but tends to quickly coat chimneys with a layer of tar[].

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[, , , ].