FENCE

barrier erected to confine or exclude people or animals, to define boundaries, or to decorate. Timber, earth, stone, and metal are widely used for fencing. Fences of living plants have been made in many places, such as the hedges of Great Britain and continental Europe and the cactus fences of Latin America. In well-timbered country, such as colonial and 19th-century North America, many patterns of timber fence were developed, such as the split rail laid zigzag, the post rail, and the picket. On the East European Plain and in the western United States, fences of turf were erected that often stood for years in the absence of heavy rains. Wire, the preeminent modern fencing material, was first used in the mid-19th century, with the development of methods of mass production. Woven wire fences, affixed to wood, steel, or concrete posts, proved economical and durable (wood posts may be treated with preservative). The invention of the barbed-wire fence in the 1860s and of a machine for its manufacture in 1874 made possible effective fencing of cattle range (see barbed wire). Electrified fences, frequently a single strand of barbed wire, are sometimes used for temporary confinement of animals. A mild shock is given to the animal at intervals of a few seconds if it is in contact with the fence.