FOREST BIOME

Forests occupy approximately one-third of Earth’s land area, account for over two-thirds of the leaf area of land plants, and
contain about 70% of carbon present in living things. Present-day forests are dominated by trees and other woody vegetation. There are three major types of forests, classified according to latitude: tropical, temperate, and taiga.

Tropical Forest

• Tropical forests have great diversity of species.
• They occur near the equator, within the area bounded by latitudes 23.5 degrees N and 23.5 degrees S.
• There are only two seasons (rainy and dry). The length of daylight is always 12 hours.
• Temperature is on average 20-25° C and varies little throughout the year.
• Precipitation is evenly distributed throughout the year, with annual rainfall exceeding 2000 mm.
• Soil is nutrient-poor and acidic. Decomposition is rapid.
• Canopy in tropical forests is multilayered and continuous, allowing little light penetration. Flora is highly diverse: one square kilometer may contain as many as 100 different tree species. Trees are 25-35 m tall, with buttressed trunks and shallow roots and large dark green leaves. Plants such as orchids, bromeliads, vines, ferns, mosses, and palms are present in tropical forests.
• Fauna include numerous birds, bats, small mammals, and insects.

Temperate forest

• Temperate forests have seasons with a distinct winter.
• Moderate climate and a growing season of 140-200 days during 4-6 frost-free months distinguish temperate forests.
• Temperature varies from -30° C to 30° C.
• Precipitation (75-150 cm) is distributed evenly throughout the year.
• Soil is fertile, enriched with decaying litter.
• Canopy is moderately dense and allows light to penetrate, resulting in well-developed and richly diversified understory vegetation and stratification of animals. Flora is characterized by 3-4 tree species per square kilometer. Trees are distinguished by broad leaves that are lost annually and include such species as oak, hickory, beech, hemlock, maple, basswood, cottonwood, elm, willow, and spring-flowering herbs.
• Fauna is represented by squirrels, rabbits, skunks, birds, deer, mountain lion, bobcat, timber wolf, fox, and black bear.
• Only scattered remnants of original temperate forests remain.

Taiga

• Taiga is the largest terrestial biome, occuring between 50 and 60 degrees north latitudes
• Seasons are divided into short, moist, and moderately warm summers and long, cold, and dry winters.
• The length of the growing season in taiga forests is 130 days.
• Precipitation is primarily in the form of snow, 40-100 cm annually.
• Soil is thin, nutrient-poor, and acidic.
• Canopy permits low light penetration, and as a result, understory is limited.
• Flora are mostly evergreen conifers, pine, fir, and spruce.
• Fauna include woodpeckers, hawks, moose, bear, weasel, lynx, fox, wolf, deer, hares, chipmunks, shrews, and bats.
• Current extensive logging in taiga forests may soon cause their disappearance.

edited from information on UCMP The World's Biomes website