forests of deciduous (summer-green) trees with broad laminae. Broad-leaved forests are widespread in eastern North America, Europe, North China, and Japan as the native vegetation between the coniferous and boreal forests of the north and the steppes and the Mediterranean, or subtropical, vegetation of the south.
Broad-leaved forests are confined to humid and moderately humid regions with lessened continentality, even annual distribution of precipitation, and relatively high temperatures. Gray, dark gray, and brown forest soils are characteristic, with chernozems sometimes occurring.
The trees in broad-leaved forests constitute the first and second layers of foliage. An undergrowth stratum of shrubs makes up the third layer, and grasses and low brush make up the fourth and fifth layers. Beech and oak broad-leaved forests predominate in Europe, with hornbeam and linden forests less common. In addition to the principal trees, ash, elm, and maple commonly occur in European broad-leaved forests. In North America maple-beech, oak-hickory, and oak forests are most widespread. Oak-chestnut forests were common there until the chestnut was wiped out by the parasitic fungus Endothia parasítica. Other frequently encountered trees are the tulip tree, liquidambar, and American linden. In coniferous-broad-leaved forests, pines, spruces, larches, and other coniferous species constitute a significant part of the stand. Common members of the understory in the broad-leaved forests of Eastern Europe are hazel, hedge maple, Tatar maple, European bird cherry, and spindle tree. Mesophyllic eutrophic or mesotrophic species predominate in the grass cover of the broad-leaved forests; prominent species in European forests are mercury, goutweed, dead nettle, wild ginger, lungwort, woodruff, and hairy sedge. Vernal ephemeroid geophytes, whose leaves open and whose seeds mature before foliage appears on the trees, also are characteristic. Common species are corydalis, anemone, toothwort, snowdrop, squill, and star-of-Bethlehem.
In the southern hemisphere forests of evergreen beech (Nothofagus) are classified as broad-leaved forests.
REFERENCESRastitel’nyi pokrov SSSR: Poiasnitel’nyi tekst k “Geobotanicheskoi karte SSSR.” Moscow-Leningrad, 1956.
Schmithüsen, J. Obshchaia geografiia rastitel’nosti. Moscow, 1966. (Translated from German.)
Walter, H. Rastitel’nost’ zemnogo shara, vol. 2. Moscow, 1974. (Translated from German.)
Tolmachev, A. I. Vvedenie v geografilu rastenii. Leningrad, 1974.
O. V. SMIRNOVA