Temperate broadleaf and mixed forests
Temperate broadleaf and mixed forest is a temperate climate terrestrial habitat type defined by the World Wide Fund for Nature, with broadleaf tree ecoregions, and with conifer and broadleaf tree mixed coniferous forest ecoregions. These forests are richest and most distinctive in central China and eastern North America, with some other globally distinctive ecoregions in the Caucasus, the Himalayas, Southern Europe, Australasia, Southwestern South America and the Russian Far East. Ecology. The typical structure of these forests includes four layers. Trees. In the Northern hemisphere, characteristic dominant broadleaf trees in this biome include oaks ("Quercus  spp.), beeches (Fagus" spp.), maples ("Acer" spp.), or birches ("Betula" spp.). The term "mixed forest" comes from the inclusion of coniferous trees as a canopy component of some of these forests. Typical coniferous trees include pines ("Pinus" spp.), firs ("Abies" spp.), and spruces ("Picea" spp.). In some areas of this biome, the conifers may be a more important canopy species than the broadleaf species. In the Southern Hemisphere, endemic genera such as "Nothofagus" and "Eucalyptus" occupy this biome, and most coniferous trees (members of the Araucariaceae and Podocarpaceae) occur in mixtures with broadleaf species, and are classed as broadleaf and  mixed forests. Climate. Temperate broadleaf and mixed forests occur in areas with distinct warm and cool seasons that give them moderate annual average temperatures — . These forests occur in relatively warm and rainy climates, sometimes also with a distinct dry season. A dry season occurs in the winter in East Asia and in summer on the wet fringe of the Mediterranean climate zones. Other areas, as central eastern North America, have a fairly even distribution of rainfall; annual rainfall is typically over and often over , though it can go as low as in some parts of the Middle East and close  to in the mountains of New Zealand and the Azores. Temperatures are typically moderate except in parts of Asia such as Ussuriland, where temperate forests can occur despite very harsh conditions with very cold winters. The climates are typically humid for much of the year, usually appearing in the humid subtropical climate without summer being extremely hot and winter very mild, and in the humid continental climate zones to the south of tundra and the generally subarctic taiga. In the Köppen climate classification they are represented respectively by "Cfa", "Dfa/Dfb" southern range and "Cfb", and more rarely, "Csb", "BSk  and Csa".