Temperate deciduous forests are broadleaf woodlands located in mid-latitude regions. Characterized by distinct seasons with cold winters and warm, wet summers, trees in this biome shed their leaves annually each autumn.
They represent the most extensive temperate forest type, comprising over 60 percent of temperate zone forests compared to 35 to 38 percent for coniferous and coniferous-deciduous mixed forests and under 2 percent for temperate rainforests. Altogether, temperate forests account for roughly 17 percent of the world's total forest area, versus about 45 percent for tropical forests and 28 percent for boreal forests.
Temperate forests as a whole store around 34 percent of the world's total forest carbon. In terms of living biomass, mature temperate deciduous forests typically hold 190 to 380 metric tons per hectare, which is substantially less than tropical rainforests, but more than boreal forests.
Temperate deciduous forests are intermediate in global biodiversity. They support the highest richness of understory plant and animal (including insect) species among temperate types. While tropical rainforests hold the highest overall terrestrial species count and temperate rainforests the highest biomass, temperate deciduous forests still outpace coniferous forests, which are hindered by acidic soils and dense canopies. However, deciduous forests often yield in overall diversity to mixed forests due to ecotone (a transition zone between two distinct ecosystems) effects.
Historically, these forests have been heavily reduced by agriculture, logging and urban expansion, leaving only about one-third of their original area. In recent decades, forest area has stabilized or rebounded in North America, Europe and parts of East Asia as a result of the abandoning of farmland, although these secondary forests are often greatly simplified and lack the rich structural and species diversity of original old-growth systems. Moreover, fragmentation and repeated harvesting also compromise overall habitat quality and ecological continuity. Globally, post-2000 losses in the temperate and boreal regions result largely from temporary events such as logging and fire rather than permanent deforestation, and net declines remain modest compared to the severe losses in the tropical regions.