Forests

Forests influence the human life directly and indirectly. Forests provide us with various foods and resources. We obtain wood for fuel, buildings, agricultural implements, furniture and paper. Gum, resin, wild rubber are also collected from forests. Indirectly they check the environmental pollution and help in conserving the soil. They are a source of oxygen and sinks for carbon. By supporting variety of flora and fauna, they play a crucial ecological role too.

Forestless Regions

The two main forestless areas are the polar regions, where the growing seasons is short, the ground is ice covered and where rainfall is also very low and the deserts where rainfall is too low (below 225 mm/10 inches) and where the soils are thin, sandy or saline.

Types of Forests

1.         Tropical Hardwood Forests: Found in the regions of high temperature and high rainfall. It includes equatorial and monsoon forests. The equatorial forests extend between 5o north and 5o south of the equator. They are found in the Zaire basin of Africa, the Amazon basin of South America and with some modifications in Malaysia and Indonesia. The equatorial forests in the Amazon basin are also known as Selvas. These are very dense forests marked by tall, green, hard wood trees. Mahogany, Rosewood and Ebony are important trees. Monsoon forests are found in central and northeast India, Myanmar, Vietnam, Thailand, Laos and Cambodia. Sal, Teak and Sisam are important trees of the region.

2.         Temperate Deciduous Hardwood Forests: Central and Western Europe, North-Eastern U.S.A. Central America and eastern Asia have the hard wood deciduous forests. The trees shed their leaves at the onset of winter. Woods are strong, durable, lighter and easier to work on. Important trees are oak, birch, chestnut, maple, Walnut and elm. They are used as building material and for the shipbuilding industry. These forests are densely populated.

3.         Temperate coniferous softwood forests of Taiga- Located between 50o N and 70oN latitudes. They are found in the northern hemisphere running through Canada, Norway, Sweden. Thailand and Central and Eastern Siberia. In Siberia, they are known as taiga forests. They are found on the mountain slopes, between altitudes of 1500 and 2000 meters. These trees are tall, straight with narrow needle like leaves. Most of these trees are evergreen. Pine, cedar, spruce, fir, red wood are some of the important trees.

Biome

It refers to any major ecological community of organism, both plant and animal, usually characterized by the dominant vegetation type, for example Tundra biomes, Tropical Rain Forest biomes, etc. In simpler terms a biome is a large ecosystem where plants, animals, insects, and people live in a certain type of climate.

Biomes are defined in terms of the entire community of living organisms and of their relationships with their immediate environment (and not only with the botanical habitat). Biomes extend over large areas and broadly correspond with climatic regions; characteristic biomes have been identified for all the major climatic regions, emphasizing the ability of living organisms to adapt to a wide variety of environments.

MAJOR BIOMES

Arctic Tundra

The Arctic tundra is a cold, vast, treeless area of low, swampy plains in the far north around the Arctic Ocean. It includes the northern lands of Europe (Lapland and Scandinavia), Asia (Siberia), and North America (Alaska and Canada), as well as most of Greenland. Another type of tundra is the alpine tundra, which is a biome that exists at the tops of high mountains.

Special features:

This is the earth's coldest biome. Since the sun does not rise for nearly six months of the year, it is not unusual for the temperature to be below -30°F in winter. The earth of the Arctic tundra has permanently frozen subsoil, called permafrost, which makes it impossible for trees to grow. Frozen prehistoric animal remains have been found preserved in the permafrost.

In summer, a thin layer of topsoil thaws and creates many pools, lakes, and marshes, a haven for mosquitoes, midges, and blackflies. More than 100 species of migrant birds are attracted by the insect food and the safe feeding ground of the tundra. Other animals that live in this biome include polar bears, Arctic foxes, caribou, and grey wolves. Plants that you might find include small shrubs and cushion plants, and the lichen which cover the many rocks on the tundra's terrain. The Arctic is also famous for the beauty of its flowers during early autumn.

Coniferous Forest

The coniferous forest biome is south of the Arctic tundra. It stretches from Alaska straight across North America to the Atlantic Ocean and across Eurasia. The largest stretch of coniferous forest in the world, circling the earth in the Northern Hemisphere, is called the “taiga.” It supplies the bulk of the world's commercial softwood timber, which is used to make paper.

Special features:

These forests consist mainly of cone-bearing trees such as spruce, hemlock, and fir, which are well suited to the cold climate. The soil is not very fertile however, because there are no leaves to decompose and enrich it. Some animals that thrive in this biome are the ermine, the moose, the red fox, the snowshoe rabbit, and birds such as the crossbill and the great horned owl.

Deciduous Forest

This biome is in the mild temperate zone of the earth. Major regions are found in eastern North America, Europe, and eastern Asia.

Special features:

Deciduous trees lose their leaves in fall. The natural decaying of the fallen leaves enriches the soil and supports all kinds of plant and animal life. The deciduous forest is a lively place, where oak, beech, ash, and maple trees are typical, and wildflowers, berries, and many types of insect and animal life abound. But the fertile soil is also good for people, and in Europe most of the deciduous forest has been destroyed to make room for farms and homes.

Desert

A desert is an area where little or no life exists because of a lack of water. Scientists estimate that about one-fifth of the earth's land surface is desert. Deserts can be found on every continent except Europe. There are two different kinds: hot and dry (such as the Arabian and Sahara deserts) and cold and dry (such as Antarctica and the Gobi desert).

Special features:

The lack of water and intense heat or cold makes this biome inhospitable to most life forms. Most of the plants you'll see in the desert are species of cactus. You might come across yucca, aloe, ocotillo plants, or the tall saguaro cacti. A few animals—mainly reptiles, like snakes and lizards are well adapted to the hot desert. Another famous desert animal is the camel, which can make water from the fat it stores in its hump. The penguins are well-known animals living at the edge of the Antarctic desert.

Grasslands

Grasslands are places with dry climates that are perfect for growing food. They are known throughout the world by different names. In the U.S. they are called prairies and extend from the Midwest to the Rocky Mountains. In South Africa, grasslands are called the veld. Hot, tropical grasslands called savannas are found in South America and Africa. In Eurasia, temperate zone grasslands are called steppes; in South America, pampas.

Special features:

This inland biome is made of vast areas of grassy field. It receives so little rain that very few trees can grow. The U.S. prairies are used to graze cattle and to raise cereal crops. There is little variety of animal life. Some original prairie animals like the wolf and bison have come close to being eliminated from the habitat by hunters. Today, some of the most common grassland animals include the prairie dog and the mule deer in North America, the giraffe and the zebra in Africa, and the lion in Africa and Asia.

Mountains

Mountains exist on all the continents of the earth. Many of the world's mountains lie in two great belts. The Circum-Pacific chain, often called the Ring of Fire, runs from the west coast of the Americas through New Zealand and Australia and up through the Philippines to Japan. The other major belt, called the Alpine-Himalayan, or Tethyan system, stretches from the Pyrenees in Spain and France through the Alps and on to the Himalayas before ending in Indonesia.

Special features:

Mountains are usually found in groups called chains or ranges, although some stand alone. A mountain biome is very cold and windy. The higher the mountain, the colder and windier the environment. There is also less oxygen at high elevations. The animals of this biome have adapted to the cold, the lack of oxygen, and the rugged landscape. They include the mountain goat, ibex (wild goat), sheep, mountain lion, puma, and yak. All of them are an excellent climber, which means they can move freely in the steep, rocky landscape. Types of plants vary depending on geographic location and altitude. Lower elevations are commonly covered by forests, while very high elevations are usually treeless.

Rainforests

Tropical rainforests are found along the equator in Asia, Africa, South America, Central America, and on many of the Pacific islands. Almost half of the world's tropical rainforests are in the South American country Brazil.

Special features:

Tropical rainforests receive at least 70 inches of rain each year and have more species of plants and animals than any other biome. Many of the plants used in medicine can only be found in tropical rainforests. The combination of heat and moisture makes this biome the perfect environment for more than 15 million plants and animals. The thick vegetation absorbs moisture, which then evaporates and completes the cycle by falling again as rain.

A rainforest grows in three levels. The canopy, or tallest level, has trees between 100 and 200 feet tall. They block most of the sunlight from the levels below. The second level, or understory, contains a mix of small trees, vines, and palms as well as shrubs and ferns. The third and lowest level is the forest floor, where herbs, mosses, and fungi grow.

Some of the animals of the tropical rainforest are the anteater, jaguar, brocket deer, lemur, orangutan, marmoset, macaw, parrot, sloth, and toucan. Among the many plant species are bamboo, banana trees, rubber trees, and cassava.

Biosphere Reserve

Biosphere reserve is any terrestrial or coastal environment that has been internationally recognized as an area for Conservation study and sustained development (as distinct from exploitative development).  Biosphere reserves form an international network of protected areas approved by the International Coordinating Council of UNESCO’S Man and the Biosphere Programme.  In conjunction with the Convention on International Trade in Endangered Species, a total of 194 different bio-geographical provinces have been identified and for each of which at least one biosphere reserve is considered necessary. By December 1985, 243 biosphere reserves had been established in 65 different countries and covering 100 of the bio-geographical provinces.  Marine provinces, however, are poorly represented.

Each reserve must contain an ecosystem that is typical of a bio-geographical realm in terms of its naturalness, diversity and effectiveness as a conservation unit.  Each reserve must exhibit minimal disturbance. Within each reserve at least one core area must exist within which no interference with the natural ecosystems is permitted.  Surrounding the core area there is a transition zone within which experimental research is permitted and beyond this lies a buffer zone, which protects the whole biosphere reserve from agricultural, industrial, and urban land use pressures.

Natural Vegetation of the World