Birch bark

From Wikipedia, the free encyclopedia

Birch bark or birchbark is generally understood to be the bark of the Paper Birch tree (Betula papyrifera), or sometimes of related species such as Gray (Wire) Birch (Betula populifolia).

The strong and water-resistant cardboard-like bark can be easily cut, bent, and sewn, which made it a valuable building, crafting, and writing material, since pre-historic times. Even today birch bark remains a popular material for various handcrafts and arts.

Birch bark also contains substances of medicinal and chemical interest. Some of those products (such as betulin) also have fungicidal properties that help preserve bark artifacts, as well as food preserved in bark containers.

A Russian birch bark letter (14th century).

1 Collection and storage
2 Working
3 Uses
4 See also
5 External links
6 References

[edit] Collection and storage

Birch bark can be removed fairly easily from the trunk or branches, living or recently dead, by cutting a slit lengthwise through the bark and pulling or prying it away from the wood. The best time for collection is spring or early summer, as the bark is of better quality and most easily removed.

Removing the outer (light) layer of bark from the trunk of a living tree may not kill it, but probably weakens it and makes it more prone to infections. Removal of the inner (dark) layer, the phloem, kills the tree by preventing the flow of sap to the roots.

To prevent it from rolling up during storage, the bark should be spread open and kept pressed flat.

[edit] Working

Birch bark can be cut with a sharp knife, and worked like cardboard. For sharp bending, the fold should be scored first with a blunt stylus.

Fresh bark can be worked as is; bark that has dried up (before or after collection) should be softened by steaming, by soaking in warm water, or over a fire.

[edit] Uses

Birch bark was a valuable material in any part of the world where birch trees were available. Containers like wrappings, bags, baskets, boxes, or quivers were made by most societies well before pottery was invented. Other uses include:

In Scandinavia and Finland, it was a valuable construction material when constructing roofs. For thousands of years it has been used for making shoes, see e.g. the Egtved Girl.
In Russia Birch bark documents have been found from the Middle Ages.
In North America the native population used birch bark for canoes, wigwams, scrolls, torches, fans, musical instruments, clothing, and more.
In Afghanistan, the oldest known Buddhist manuscripts (some of the Gandharan Buddhist Texts) were written on birch bark.
Birch bark makes an outstanding tinder, as the inner layers will stay dry even through heavy rainstorms. To render birch bark useless as tinder, it must be soaked for an extended period.