Bark (botany) rope, used for example in the rigging of Viking age longships. Among the commercial products made from bark are cork, cinnamon, quinine (from the bark of Cinchona) and aspirin (from the bark of willow trees). The bark of some trees notably oak ("Quercus robur") is a source of tannic acid, which is used in tanning. Bark chips generated as a by-product of lumber production are often used in bark mulch in western North America. Bark is important to the horticultural industry since in shredded form it is used for plants that do not thrive in ordinary soil, such as epiphytes.
Bark hack The first sentence is basically correct except that the blade is straight rather than curved. With the bark hack, only the bark is removed; it does not cut into the wood as the wood hack did. The wood hack was used up until the early 1950's and the trees were "chipped or streaked" each week during the sap flow season. With the bark hack, only the bark was removed and a 50% sulfuric acid solution was sprayed on the "streak" and it had to be done only every 2 weeks. Bark hack A bark hack is a tool used to