Terrestrial Ecosystems

Forests

• The word forest is derived from the Latin word ‘foris’ meaning outside, the reference being to village boundary fence that must have included all uncultivated and uninhabited land. The forest ecosystem includes a complex assemblage of different kinds of biotic communities. The nature of soil, climate and local topography determine the distribution of trees and their abundance in the forest vegetation.

i) Coniferous Forest:

• Cold regions with high rainfall and strongly seasonal climates with long winters and fairly short summers are characterised by boreal coniferous forest which is transcontinental.
• These forests are characterised by evergreen plant species such as spruce, fir and pine trees and by animals such as the lynx, wolf, bear, red fox, porcupine, squirrel, and amphibians like tree frogs and pond frogs.
• The litter resultant from conifer needles is broken down very slowly and is not particularly rich in nutrients. These soils are acidic and are mineral deficient. The productivity and community stability of boreal forests are lower than those of any other ecosystem.

ii) Temperate Deciduous Forest:

• The temperate forests are characterised by a moderate climate and broad-leafed deciduous trees, which shed their leaves in winter and grow new foliage in the spring.
• These forests are characteristic of North America, Europe, Eastern Asia (including China and Japan), Chile and part of Australia with a cold winter and an annual rainfall of 75-150 cm. The precipitation may be fairly uniform throughout year.
• Trees are quite tall about 40-50 m in height and their leaves are thin and broad. The predominant genera of this biome are maple, beech, oak, hickory, basswood, chestnut, and cottonwood. In Himalayas, the temperate vegetation includes pines, cedars, fir and juniper trees along with rhododendrons and willow.
• The common animals are deers, bears, squirrels, gray foxes, bobcats, wild turkey and woodpeckers. Common invertebrates include earthworms, snails, millipedes, coleoptera and orthoptera. Vertebrates include amphibians such as toad, salamander, cricket and frog, reptiles such as turtle, lizard and snake, mammals such as racoon, opossum, pig and mountain lion, and birds like horned owl and hawks.

iii) Temperate Evergreen Forest:

• Many parts of the world have a Mediterranean type of climate which is characterised by warm, dry summers and cool, moist winters. These are commonly inhabited by low evergreen trees having needle-like or broad leaves. These include hemlock, yew and maple .Shrubs may range up to 3-4m in height. The characteristic animals of temperate evergreen woodland chaparral are mule, deer, brush rabbit, wood rat, chipmunk and lizard.

iv) Temperate Rain Forest:

• The temperate rain forests are colder than any other rainforest and exhibit a marked seasonality with regard to temperature and rainfall. Rainfall is high, but fog may be very heavy which may actually represent a more important source of water than rainfall itself. The diversity of plant and animals is much low as compared to their warmer counterparts.

v) Tropical Rain Forest:

• Tropical rain forests occur near the equator, and are among the most diverse communities on the earth. Both temperature and humidity remain high and more or less uniform. The annual rainfall exceeds 200 cm and is generally distributed throughout the year.
• The common vertebrates of tropical rain forests are the arboreal amphibian Rhacophorus malabaricus, aquatic reptiles, chameleons, agamids, geckos, many species of snakes and birds, and a variety of mammal such as leopard, jungle cats, anteaters, giant flying squirrels, monkeys and sloths.

vi) Tropical Seasonal Forest: 

• Tropical seasonal forests occur in regions where total annual rainfall is very high but segregated into pronounced wet and dry periods. In exceedingly wet tropical seasonal forests, commonly known as monsoon forests, the annual precipitation may be several times that of the tropical rainforests. Teak is often a major large tree in the best known tropical seasonal forests of India (central India) and South East Asia. Bamboo is also an important climax shrub in these areas.

vii) Subtropical Rain Forest:

• In regions of fairly high rainfall but less temperature difference between winter and summer, broad-leaved evergreen subtropical forest is found. The vegetation includes mahogany, palms, oaks, magnolias and tamarind, all laden with epiphytes (of Pineapple and orchid families), ferns, vines and strangler fig. (Ficus aureus). Animal life of subtropical forest is very similar to that of tropical rainforests.