Temperate Deciduous Forest
Although the temperate region is technically located between of the Polar rings and the Tropics (Cancer and Capricorn), when we refer to the temperate forests we usually mean an area that occupies the mid-Atlantic and north-eastern portions of the United States into Canada, as well as parts of Europe, Russia, Japan, eastern China, N.W. Zealand, S.E. Australia, S. Chile, as well as the east coast of Paraguay.
The dominant and obvious flora in this biome is large, deciduous, broad-leafed (flowering) hardwood trees. Coniferous trees occur in mixed stands in some areas, but tend not to dominate. The understory is a mix of saplings, understory trees, and shrubs. The forest floor is covered with springtime flowering perennials, ferns, mosses, and fungi. More than 600 species of trees and shrubs extend from Canada down to sub-tropical areas of the United States. Some trees like red maple (Acer rubrum) can be found in every state in the USA.
Climate
5-7 month growing season
Four distinct seasons: summers are active and warm; autumn is cool and dry and a time of preparation; winters are dormant and cold with frost; and spring is cool, wet, and active
Rainfall
75 - 220 cm/yr (28-85 in/yr) of precipitation all year.
Temperature
Annual average between 5°-17°C
The average annual temperature is 10° C.
Regional Expressions
Eastern North America, parts of Europe, eastern China, Japan, Russia, NW Zealand, SE Australia, So. Chile, as well as the east coast of Paraguay
Above: A Whittaker Graph showing where temperate deciduous forests occupy this abiotic space, based on precipitation and temperature
Soils
Autumn leaf fall provides for an abundant and rich humus which begins to decay rapidly in spring
Brown forest soils (alfisols) form in cool to hot humid areas from the Mississippi River through the Appalachians
Ultisols: in the humid southeast United States, which are intensely weathered and support more southern conifers
Flora & Fungi
Tree canopy: The canopy contains mature trees such as oak, beech, maple, hickory, elm, sweet gum and tulip trees.
This zone has height ranges between 60 and 100 feet. Many insects and birds as well as some mammals live in the canopy.
e.g. Quercus, Acer, Fagus, Carya, Ulmus, Tilia, Juglans and Liquidambar
Understory: The understory contains saplings of canopy trees, shrubs, as well as shade-adapted trees that are naturally small in stature
Some of the shrubs in this zone are witch hazels, rhododendrons, viburnums, and blueberries. Common small trees are sassafras and dogwoods.
Herb layer: The herb layer, an area a few feet above the ground, contains soft, green, mostly perennial plants
This zone is dominated by spring-flowering plants, even when snow is still present. During the summer and fall, ferns and other forest perennials proliferate in this zone.
Forest floor: The forest floor contains small plants such as lycopods and mosses, as well as fungi, lichens, protists, and bacteria
The soil of these forests is frequently moist to wet with many small to microscopic insects.
The forest floor is home to many amphibians and mammals.
Adaptations
Deciduous leaves: avoid desiccation in drying winter
Autumn color change - e.g. using secondary pigments for photosynthesisEarly flowering herbs, called spring ephemerals
Wind-pollinated trees with catkins (e.g. oaks, ashes, birches, etc.)
Shrubs with bracts to attract pollinators (e.g. dogwoods)
Shade-tolerant shrubs and understory plants
Additional Resources
How archaeologists use hazelnuts to reconstruct ancient woodlands (Phys.org 29Feb2024)
└ Styring et al. (2024) Carbon isotope values of hazelnut shells: a new proxy for canopy density
The Badass Spring Ephemeral (In Defense of Plants, 2016)