Rapid changes from cold and dry to wet and warm or to any of the other corners of the climate envelope are often swift and dramatic. The deciduous forest has four distinct seasons, spring, summer, autumn, and winter. In the autumn the leaves change color. During the winter months the trees lose their leaves. A favorite saying among the natives is "if you don`t like the weather, wait a minute". The temperate deciduous forest climate is fairly mild. It usually consists of a cold winter, warm spring, hot summer, and a cool autumn, with a temperature range of -30° C to 30° C. temperate deciduous forest gets about 51-152 centimeters of rain every year. There is an approximately 6 month growing season. The 20 to 60 inches of precipitation is distributed evenly throughout the year. The non-growing season is due to temperature-induced drought during the cold winters. The shortening days of fall stimulate the plants to withdraw chlorophyll from their leaves, allowing a brief but beautiful display of other pigments before the leaves are shed completely and plants enter an extended period of dormancy.

The plants of this biome must be very well adapted to survive in these conditions. Many of the same genera, previously part of an Arcto-Tertiary Geoflora, are common to all three of the disjunct northern hemisphere expressions of this biome. Included among these genera are Quercus (oak), Acer (maple), Fagus (beech), Castanea (chestnut), Carya (hickory), Ulmus (elm), Tilia (basswood or linden), Juglans (walnut), and Liquidamber (sweet gum). Different species of these genera occur on each continent. In the temperate deciduous forests there are five different zones, the first zone being he Tree Stratum zone, which contains trees like as oak, beech, maple, chestnut hickory, elm, basswood, linden, walnut, and sweet gum trees. The height of trees in this zone ranges between 60 and 100 feet. The second zone is the small tree and sapling zone, having young and short trees. The third zone or the shrub zone consists of rhododendrons, azaleas, mountain laurel, and huckleberries. The Herb zone is the fourth zone containing short, herbal plants. The final zone is the Ground zone containing lichen, club mosses, and true mosses. Oaks are one of the dominant tree species in the deciduous forest, at least in North America. Many of the dominant species produce very large seeds; the large seed contains enough food to sustain the seedling as it grows up through the leaf litter into the shaded world of the forest floor. Other important trees include hickories and walnuts (right); formerly the chestnut was a dominant tree until the chestnut blight was introduced and decimated this key species. Maples, beech, sycamores and a host of other trees also play a role in the forest and we will meet some of them later.

Wildflowers, here represented by Dutchman`s Breeches are also common in the forest, although they need some unusual strategies to survive on the heavily shaded forest floor. Many bloom early in the spring, before the big trees have leafed out, and may shed their leaves and remain dormant underground through the remainder of the summer. Other trees play a role in the succession leading up to a mature forest. These trees are found in abandoned farm fields that are reverting to forest, or in clearings caused by natural events such as tornados, windstorms or fires. The Redbud is most noticeable in the spring when its pink flowers add a touch of color to the woods, and sassafras has interesting leaves and tasty extracts which are made into tea.

The animals adapt to the climate by hibernating in the winter and living off the land in the other three seasons. The animals have adapted to the land by trying the plants in the forest to see if they are good to eat for a good supply of food. Also the trees provide shelter for them. Animal use the trees for food and a water sources. Most of the animals are camouflaged to look like the ground. Characteristic members of the fauna are either mast-eaters (nut and acorn feeders) or omnivores. Mammals show adaptations to an arboreal life; a few hibernate during the winter months. North American herbivores include whitetail deer, gray squirrel, and chipmunk. They feed on the mast (the nuts and seeds) that falls to the forest floor, although squirrels eat these on the tree itself. Omnivores include raccoon, opossum, skunk, and black bear. Carnivores have been largely eliminated through the deliberate effort of humans but should include timber wolves, mountain lions, and bobcats. The coyote, native to the western grasslands and deserts, has recently dispersed east and taken over the niche of its departed cousin, the timber wolf. Birds of all sorts make the forest home. In particular, many songbirds migrate north to the temperate forest from winter stays in Central or South America. The flush of insects in the spring, along with the long days of spring and early summer make it possible for the birds to raise more young. The Yellow-breasted chat is typical of this type of bird.

Resident bird species also tend to be seedeaters or omnivores. Many, like the several species of woodpeckers and the chickadees, are cavity-nesters. The loud, conspicuous blue jay is a major agent in the dispersal of oaks onto abandoned farmland and pastures. Migratory species tend to be insectivorous and include many so-called neotropical migrants, including warblers, wrens, thrushes, tanagers, and hummingbirds.

The soil is very fertile. In fact, some of the great agricultural regions are found in this biome. That is one of the reasons there aren`t a lot of original deciduous forests left in the world. Almost all of the forests in North America are second growth forests but it still has the biggest variety of original plant species. In Europe there are only a few species of original trees left. Most of the forests have been cleared for agriculture. China has been clearing the natural trees for at least 4,000 years and most of the forests are man-made. Broadleaf trees tend to be nutrient demanding and their leaves bind the major nutrient bases. Thus the litter under this forest is not as acidic as under needleleaf trees and aluminum and iron are not mobilized from the A-horizon. The autumn leaf fall provides for abundant and rich humus, which begins to decay rapidly in spring just as the growing season begins. Distinctive red or yellow subsoils have developed under the warmer climate.

A lot of deciduous forests have lost land to farms and towns. Although people are trying to protect the forests some poachers are trying to kill the animals in the forests. The animals are losing their homes because of people building their homes. Humans have often colonized places in the temperate deciduous forest. Because of this, a substantial percentage of the human race lives in the temperate deciduous forest. It is no coincidence that a good deal of the human population is found in areas that once supported temperate forests. The soils are rich and easily converted to agriculture. The climate is warmer than the boreal forest, yet not so warm as the tropics. One of the problems with the tropics is the prevalence of parasitic diseases found there, many transmitted by mosquitoes or other insects - and this is less of a problem in temperate areas where the onset of winter causes mosquito populations to crash. So, the biggest threat to temperate forests is once again development and agriculture. Other threats to the forest come from logging; most of the trees here are hardwoods, which means they have a denser wood than most of the coniferous trees. It also means they may grow more slowly, which means more pressure to cut the trees to maintain volume at the sawmill. Acid Rain from coal burning is another threat, as is global warming, which in particular may change rainfall patterns.

The Northern Dry Deciduous Forests eco-region is neither exceptionally species-rich nor high in numbers of endemic species. But it does harbor several large vertebrates, including Asia`s largest and most charismatic carnivore, the tiger (Panthera tigris). This eco-region also represents the northernmost extent of dry deciduous forests in India. The ecoregion extends across the Indian states of Bihar, Orissa, and Madhya Pradesh. It represents a north-south-directed island of dry deciduous forests in the rainshadow of the Eastern Ghats Mountain Range and is completely surrounded by the Eastern Highlands Moist Deciduous Forests. Most of these forests are open scrub influenced by human activities. The original sal dominated, multistoried vegetation has been replaced by teak, which favors drier conditions. In many areas, intensive livestock grazing, fire, and non-timber forest product harvest have converted the habitat to scrub and savanna woodland.

The Kathiawar-Gir forests in the main part of the ecoregion comprises the Aravalli Range and the eastern half of Rajasthan state, extending into eastern Gujarat and the Malwa region of Madhya Pradesh. The drier Northwestern thorn scrub forests ecoregion lies to the west, covering the remainder of the Kathiawar Peninsula and the strip of western Rajasthan between the Aravalli Range and the Thar Desert. To the northwest the Kathiawar-Gir dry deciduous forests transition to the Upper Gangetic Plains moist deciduous forests. To the southeast lies the Narmada Valley dry deciduous forests ecoregion, which covers the Vindhya Range and Narmada River valley.

Like many of the Deccan Plateau dry forest eco-regions, this region does not harbor large numbers of endemic species, nor is it exceptionally rich in biodiversity. The known mammal fauna consists of sixty-eight species. There are no eco-regional endemic species, but the threatened species include the tiger, wild dog sloth bear and chousingha. Land clearing and degradation remain the primary threat to the remaining habitat. Fires are regularly set to encourage grazing lands for livestock. Extensive poaching and collection of nontimber forest products by the tribal communities are also a serious concern. But degradation threats from industry and timer companies also are high. The large tribal populations in these areas are also shifting from subsistence to more materially demanding lifestyles.