Birch bark or birchbark is the bark of several Eurasian and North American birch trees of the genus Betula.

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 type of wood for various handicrafts 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.

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.

Raymond Paul "Ray" Mears (born 7 February 1964) is an English woodsman, instructor, author and TV presenter. His TV appearances cover bushcraft and survival techniques, and he is best known for the TV series Ray Mears' Bushcraft, Ray Mears' World of Survival, Extreme Survival, Survival with Ray Mears, Wild Britain with Ray Mears and Ray Mears Goes Walkabout.

Mears grew up in Kenley, Greater London, and the North Downs, where he discovered a countryside abundant with wildlife. Educated at Reigate Grammar School, a co-educational independent school in Reigate, Surrey, he learned to track foxes in the forest at a young age. As a boy, he desired to sleep out on the trail, but unable to afford camping equipment, he resorted to setting up camp using what he could find in his surroundings.

Mears's enthusiasm for his subject, combined with his broad knowledge of survival and the uses which may be made of plants, trees and other natural materials found in woodland, forest or desert, have made him a popular figure in TV broadcasting in the UK.^{[citation needed]} He has travelled extensively across the world for his TV series and has learned survival techniques from the indigenous peoples he has met. In his programmes he demonstrates his knowledge of the wild, how to find food from seeds, berries, roots and other growing things, and how to survive by constructing temporary shelters, fires and canoes from natural materials.