ARBOIS ([.a]r-bwä), a town of France, department of Jura; famous for its wines. Pop. 5000.
ARBOR DAY, a day officially set apart in the United States for the annual planting of trees by the people, and especially by school-children. The custom was instituted in 1872.
ARBORE´TUM (Lat. _arbor_, a tree), a place in which a collection of different trees and shrubs is cultivated for scientific or educational purposes. The largest arboretum in Britain, perhaps the finest in the whole world, is that of the Royal Gardens, at Kew, inaugurated in 1762, to which 180 acres are now devoted. Next in celebrity are the arboreta at Edinburgh (Inverleith) and at Dublin (Glasnevin), the Botanical Gardens at Oxford, and the Botanic Gardens at Glasgow. Other arboreta are that of the Jardin des Plantes, Paris, and the Arnold Arboretum, at Jamaica Plain, Boston. The term arboretum has also been applied in a restricted sense, as in the _Arboretum Fruticetum Britannicum_, the monumental work by J. C. Loudon.
AR´BORICULTURE includes the culture of trees and shrubs, as well as all that pertains to the preparation of the soil, the sowing of the seeds, and the treatment of the plants in their young state, the preparation of the land previous to their final transplantation, their just adaptation to soil and situation, their relative growth and progress to maturity, their management during growth, and the proper season and period for felling them.
ARBOR VITÆ (literally, 'tree of life'), the name of several coniferous trees of the genus Thuja, allied to the cypress, with flattened branchlets, and small imbricated or scale-like leaves. The name is derived from valuable medicinal properties having formerly been ascribed to the aromatic resin they mostly yield. Those generally cultivated in Britain are: the common Arbor Vitæ (_Thuja occident[=a]lis_), a native of North America, where it grows to a height of 40 or 50 feet, introduced into Britain about 1566; the giant Arbor Vitæ or Red Cedar (_Thuja gigantea_), introduced in 1854; and the Chinese Arbor Vitæ (_Thuja orient[=a]lis_).
ARBROATH (ar-br[=o]th´), or ABERBROTHOCK, a royal municipal and police burgh and seaport in the county of Forfar, Scotland, at the mouth of the small River Brothock. Its ancient abbey, founded by William the Lion in 1178, and dedicated to Saints Mary and Thomas à Becket, is now a picturesque ruin. There are numerous flax and hemp spinning-mills and factories, and much canvas and linen is made; also tanning, shoemaking, and fishing, and a small shipping trade, but the harbour is bad. Pop. 19,499. It unites with Montrose, Forfar, Brechin, and Inverbervie (the Montrose burghs) in sending a member to Parliament.