An area of vegetation in which the dominant plants are trees; forests constitute major biomes. Temperate forests have adequate or abundant rainfall and moderate temperatures. They may be dominated by deciduous trees (such as oak, ash, elm, beech, or maple), often growing together to form mixed deciduous forest, as in temperate regions of Europe, Asia, and North America; or by broad-leaved evergreens (such as southern beech, Nothofagus), as in Chile. Cold forests, of northern regions, are dominated by evergreen conifers (see taiga). Tropical forests include rainforest, characterized by regular heavy rainfall; monsoon forest, found in SE Asia and having heavy rainfall interspersed with periods of drought; and thorn forest, as in SW North America, SW Africa, and parts of Central and South America and Australia, which has sparse rainfall, is dominated by small thorny trees, and grades into savanna woodland (see grassland) and semidesert. See also deforestation.