A beech of the family Fagaceae is tall, round-headed, and wide-spreading, with smooth, steel-gray bark and alternate, toothed, parallel-veined, shiny green leaves. Yellow-green male flowers hang from threadlike stems; the female flowers, usually in pairs on short, hairy stems on the same tree, develop into prickly burs enclosing three-sided, sweet-flavoured nuts.

The American beech (F. grandifolia), native to eastern North America, and the European beech (F. sylvatica), distributed throughout England and Eurasia, are the most widely known species. Both are economically important timber trees, often planted as ornamentals in Europe and North America; they may grow to 30 m (100 feet). The narrow, coarsely saw-toothed, heavily veined, blue-green leaves of the American beech are about 13 cm (5 inches) long and turn yellow in autumn; the slightly shorter, egg-shaped, dark-green leaves of the European beech turn red-brown in autumn but, in mild climates, persist through the winter.

An Asian species, the Chinese beech (F. engleriana), about 20 m (about 65 feet) tall, and the Japanese beech (F. japonica), up to 24 m (79 feet) tall, divide at the base into several stems. The Chinese and the Japanese, or Siebold's, beech (F. sieboldii) are grown as ornamentals in the Western Hemisphere. The Mexican beech, or haya (F. mexicana), a timber tree often 40 m (130 feet) tall, has wedge-shaped leaves. The Oriental beech (F. orientalis), a pyramidal Eurasian tree about 30 m (about 100 feet) tall, has a grayish-white trunk and wavy-margined, wedge-shaped leaves up to 15 cm (6 inches) long.

Pale, red-brown beech wood, durable under water, is valued for indoor use, tool handles, and shipping containers. The nuts provide forage for game animals, are used in fattening poultry, and yield an edible oil.

Beeches are often cultivated as ornamental and shade trees, especially varieties of the European beech, such as the copper, or purple, beech, with copper-coloured foliage; the Dawyck beech, a narrow, spirelike, glossy-leaved tree; the fernleaf, or cut-leaved, beech, with narrow, deeply lobed, fernlike leaves; the oak-leaved beech, with deeply toothed, wavy-margined, oaklike leaves; and the weeping beech, with long, pendulous branches and wide-spreading, horizontal limbs.

Beeches grow best in sandy loam. They are slow-growing but may live to 400 years or more. Propagation is usually by seed; the shallow, spreading root system often sends up suckers that may grow into thickets.

The wavy-leaved Antarctic beech, or nire (Nothofagus antarctica), and the roble beech (N. obliqua), both 30-m trees native to Chile and Argentina, differ from other species of false beech in being deciduous; they are planted as ornamentals on other continents. The pink-brown hardwood of the Antarctic beech is used in flooring and cabinetmaking. The remaining false beeches are evergreen timber trees of the Australasian area. Among the best known are the Australian beech (N. moorei), a 46-m-tall tree with leaves seven centimetres long, found in New South Wales; the mountain beech (N. cliffortioides), a 12-m-tall New Zealand tree with glossy, toothless leaves about one centimetre long; the myrtle beech, Tasmanian myrtle, or Australian, or red, myrtle (N. cunninghamii), a 60-m-tall Tasmanian tree important for its fine-textured wood; the slender, columnar red beech (N. fusca) of New Zealand, about 30 m tall; and the silver, or southland, beech (N. menziesii), a 30-m-tall New Zealand tree with doubly and bluntly toothed leaves bearing small, hairy pits beneath.