Sunday, August 10, 2008

Environmental Benefits of Tropical Forests

Tropical forests do more than respond to local climatic conditions; they actually influence the climate. Through transpiration, the enormous number of plants found in rain forests return huge amounts of water to the atmosphere, increasing humidity and rainfall, and cooling the air for miles around. In addition, tropical forests replenish the air by utilizing carbon dioxide and giving off oxygen. By fixing carbon they help maintain the atmospheric carbon dioxide levels low and counteract the global "greenhouse" effect.

Forests also moderate stream flow. Trees slow the onslaught of tropical downpours, use and store vast quantities of water, and help hold the soil in place. When trees are cleared, rainfall runs off more quickly, contributing to floods and erosion.

Methods of conservation of forests

The challenge of conservation is to understand the complex connections among natural resources and balance resource use with protection to ensure an adequate supply for future generations. In order to accomplish this goal, a variety of conservation methods are used. These include:
1. reducing consumption of resources
2. protecting them from contamination or pollution
3. reusing or recycling resources when possible
4. fully protecting, or preserving, resources.

Consumption of natural resources rises dramatically every year as the human population increases and standards of living rise. From 1950 to 2000 the world population more than doubled to 6 billion people, with nearly 80 percent living in developing, or poorer, nations. The large, developed nations, however, are responsible for the greatest consumption of natural resources because of their high standards of living. For instance, the average American consumes as much energy as 27 Filipinos or 370 Ethiopians.

Conservation education and the thoughtful use of resources is necessary in the developed countries to reduce natural-resource consumption. For example, reducing the high demand for tropical hardwoods such as teak and mahogany in the United States and Japan would slow the rate of tropical forest destruction.

In many cases it is possible to reuse or recycle resources to reduce waste and resource consumption. For example, paper can be recycled. Many states in the United States have established mandatory recycling laws in an attempt to reduce waste and consumption.

On the other hand, forests are so unique or valuable that they are protected from activities that would destroy or degrade them. For example, national parks and wilderness areas are protected from logging or mining in the United States because such activities would reduce the economic, recreational, and aesthetic values of the resource. Forests and wetlands (areas with high soil moisture or surface water) may be protected from development because they enhance air and water quality and provide habitat for a wide variety of plants and animals. Unfortunately, these areas are often threatened with development because it is difficult to measure the economic benefits of cleaner air, cleaner water, and the many other environmental benefits of these ecosystems (the plants and animals of a natural community and their physical environment).

The importance of conserving forests

Forests play a vital role in preventing global warming and building sustainable societies. So the need to protect and develop them can never be stressed enough. Japan's substantial forests make it a notable example. In brief, that is the message of the government report on forests and forestry released last week.

The white paper, the first to be prepared under the Forest and Forestry Basic Law that took effect last July, points out various problems, including financial ones, that stand in the way of forest conservation. The government has its work cut out: fleshing out the basic program approved by the Cabinet last October.



Forests have a variety of functions, including land conservation, securing of water sources, control of climate change, and creation of natural environs essential to human existence. The law gives new value to these "multifunctional" forests with a view to achieving harmony between them and society.

There is a hard lesson to be learned from Japan's forestry administration in the postwar period. The government applied a rigid policy to developing forestry as an industry. As a result, domestic logs lost in the price competition with imported logs. The deficit has widened, pushing forest owners and forestry associations to the brink of bankruptcy. They are so depressed, it is said, they cannot perform even the basic task of thinning out their stands of trees.

According to the report, domestic log prices have dropped to one-third of their peak of 30 years ago. The average annual income from forestry was only 260,000 yen in fiscal 2000. Forests cover 70 percent of the land, one of the highest rates among the developed countries. But imported logs account for 80 percent of the domestic demand, making Japan the world's third-largest log importer.

Recent studies prove, scientifically and economically, how important forests are. Of their various functions, those that can be measured in monetary value are worth 70 trillion yen, the report estimates. Reducing the burden on the environment and building a recycling-oriented society requires a well-defined policy focus on the utilization of domestic forests.

The relationship between forest conservation and global warming deserves special attention, given forests' great role as an absorber of carbon dioxide. Under the Kyoto treaty on climate change Japan is committed to cut emissions by 6 percent from the 1990 level in the five years between 2008 and 2012. More than half that deduction, 3.9 percent, is to be achieved through forest absorption.

The Forestry Agency, however, believes the 3.9 percent target will be impossible to achieve even if forest development is promoted at the current pace. Actual figures, it says, will probably miss the mark by a wide margin. So the pace needs to be accelerated. In the long run, it is probably also necessary to introduce a carbon tax or a water-source tax, for example, because large-scale government spending is considered unavoidable.

However, the tax approach to the global warming issue -- an issue that requires many years of patient efforts -- is taking a back seat to immediate concerns, such as tax cuts for economic recovery and tax increases for fiscal reform. This is evident from discussions at the Council on Economic and Fiscal Policy and the Tax Commission.

The report, referring to "tree culture," raises new possibilities for the mountain villages that saw their populations dwindle during the economy's rapid expansion. These depopulated areas, it says, "can set future models for efforts to create a recycling-capable society." That is a promising prospect indeed.

The report rightly says that forestry should be seen as culture, not just as an industrial sector, and that forestlands should be treated as an integral part of human activity. This is a welcome attempt to rejuvenate these heretofore neglected regions through exchanges with cities.

Forest conservation is also essential to wildlife protection. The latest conference on the biodiversity treaty in The Hague urged governments to take protective measures by 2010. Japan needs to bolster domestic efforts under the forestry conservation program adopted by the conference.

The government should also improve the vertically divided administrative system so it can take an integrated approach to forestry development, environmental protection and tax reform. Another challenge is to set rules for the shared roles between the central and local governments, and between private companies and volunteer groups. Reviving forests and villages is a grand undertaking that requires the long-term, broad-gauged participation of communities and people across the country.

Uses of Forests

People began life on this planet as forest dwellers. They were food gatherers and depended on the forest for all their needs: food, clothing, and shelter. They gradually became food growers, clearing a small patch in the forest to grow food. But they continued to depend on forests to meet a lot of their needs. Even today people depend on the forest for paper, timber, fuelwood, medicine, and fodder.

Fuelwood Fodder
Fencing Soil erosion check
Wind breaks and shelter belts Soil improvement


Fuelwood
For the rural population, wood is an important source of energy for cooking and heating. They prefer smaller stems as these are easier to collect and carry. The wood that they select should be easy to split and have low moisture content to dry faster. Some of the wood is converted to charcoal and used for cooking.

Fodder
Fodder from the forest forms an important source for cattle and other grazing animals in the hilly and the arid regions and during a drought. There are many varieties of grasses, trees, and shrubs that are nutritious for the livestock. Care is taken to see that trees poisonous to cattle are not grown. Trees that produce a large crown above the reach of cattle are preferred.

Fencing
Fences created with trees and shrubs are preferred in developing countries as they are cheap to maintain yet give protection. Species that have thorns or are prickly and have stiff branches and leaves that are not edible are preferred. These species should be fast growing, hardy, and long lived.

Wind breaks and shelter belts
Trees grown for wind breaks should be bushy and sturdy to withstand strong winds, both hot and cold. Along the Saurashtra coast in India, casuarina has successfully been planted to check degradation due to salt laden coastal winds. A species of prosopis, called P. juliflora, planted along the desert border in Haryana and Gujarat has successfully halted the advance of the desert.

Soil erosion check
Tree roots bind the soil and prevent erosion caused by wind or water. Leaf fall also provides a soil cover that further protects the soil. Casuarina planted along the coastal region has helped in binding the sand and stabilizing the sand dunes in the area.

Soil improvement
Some species of trees have the ability to return nitrogen to the soil through root decomposition or fallen leaves. Such trees are planted to increase the nitrogen content of the soil.

Forest products and their uses

Timber Grasses
Cane Medicinal use
Fruit Floss
Fibre Essential oils
Bamboo

Timber
More than 1500 species of trees are commercially exploited for timber in different parts of India. It is used in timber-based industries such as plywood, saw milling, paper and pulp, and particle boards.

Bamboo
These are common in the north-eastern and the south-western parts of India, growing along with deciduous or evergreen forest. The main commercial uses of bamboo are as timber substitutes, fodder, and raw material for basket, paper and pulp, and other small-scale industries.

Cane
Cane or rattan are the stems of a climber plant and are used for a large number of household items. It is used to make walking sticks, polo sticks, baskets, picture frames, screens, and mats.

Grasses
There are hundreds of varieties of grasses in the country that are used for a number of purposes. Lemon grass, palmrose grass, bhabbhar, and khus grass are some of them.

Fruit
Fruit trees are an important source of income and food for the rural household. In some areas fruit trees are commonly planted along the field borders and around the wells. Mango, coconut, orange, pear, jackfruit and many others grow wild in the forest.

Medicinal use
Since time immemorial humans have been depending on the forest to cure them of various ailments. Even today man is dependent on the forest for herbs and plants to fight against disease. Of all the medicinal trees found in India, the neem is the most important. Leaves, bark, and other parts of many other trees also have medicinal value and are used to make various ayurvedic medicines.

Fibre
Plant fibre has many different uses. Soft fibres such as jute are derived from the stems of the plant. Hard fibre from the leaves of hemp and sisal are used to make fabrics for various applications. Coir, another form of fibre from the fruit of the coconut, is used to make ropes.

Floss
The fruits of many species of Indian trees produce a silky floss. The most common of these is simal. It is used to made cotton wool, mattresses, and pillows.

Essential oils
Tropical grasses such as lemon grass, citronella, and khus are the source of essential oils. Oil is distilled from the wood of various species such as sandalwood, agar, and pine. Oil is also derived from the leaves of certain plants and trees such as eucalyptus, camphor, wintergreen, and pine. These oils are used for making soaps, cosmetics, incense, pharmaceuticals, and confectionery.

Benefits of Forests

The great beauty and inspirational qualities of forests belie their important biological tasks. By producing vast amounts of oxygen and water vapor, and absorbing carbon dioxide, they help support all life on Earth. A single mature oak tree produces enough oxygen to keep eight people alive for a year. In 1995, an international team of ecologists working in Brazil documented that each hectare (2.47 acres) of undisturbed tropical rainforests absorbs 1 ton of carbon dioxide per year. The world's rainforests are thus absorbing a billion tons of carbon dioxide a year, one-sixth the amount produced by burning fossil fuels such as oil and coal, according to the National Oceanic and Atmospheric Administration (NOAA). Cutting and burning of forests around the world releases carbon dioxide into the air. The high levels of carbon dioxide in the world's atmosphere have caused increases in average global temperatures. The value of tropical forests in trapping carbon dioxide is so significant that four US utility companies have sponsored a pilot program in Belize to protect large areas of forest and plant trees; energy companies will contribute $2.6 million to a 120,000-acre reserve that will absorb 5.2 million tons of carbon dioxide gas over 40 years (Geatz 1996). The Clean Air Act allows such "pollution credits" to compensate for pollution released elsewhere. In 2000, the US government proposed a massive program of tree planting and protection of forests to compensate for the effects of global warming caused by the release of carbon dioxide and other pollutants.



The cooling effect of forests results from leaf transpiration generating moisture that rises to the atmosphere, forming clouds which release water as rain or other precipitation. When forests are cut, the climate dries as rainfall decreases and soils lose moisture. Tree roots absorb about one‑half of the rain that falls, releasing the water gradually during the year (Schreiber et al. 1989). In countries with wet and dry seasons, water retention by trees makes the difference between deadly floods that kill thousands of people and sweep away their homes and precious topsoil, and river levels that remain stable, preserving soil and the environment. Forests stabilize the soil, preventing erosion and landslides and allowing streams and rivers to flow clear.



The leaves, bark and wood of trees have been found to contain hundreds of compounds valuable to medicine and industry. Forests produce a wealth of useful species: oils, gums, resins, tannins, waxes, edible oils, dyes, cosmetics, spices, fruits, nuts and life‑saving compounds used in medicine. Spices alone are worth more than $1 billion per year (Schreiber et al. 1989). Medications derived from wild plants are worth $40 billion annually (Lean and Hinrichsen 1994). Painkillers, birth‑control agents and malaria drugs, as well as quinine, digitalis and morphine, are all derived from tropical forest plants. According to one study, more than 40 percent of all prescriptions in the United States still depend on natural plant sources (Swaminathan 1990). Only a small percentage of wild plants have been tested for medicinal value. In some cases, plants that might have disappeared altogether were found to be medical treasures. The Madagascar periwinkle, native to an island which has lost 80 percent of its forests to deforestation, has been the source of two potent compounds that have proven effective in the treatment of Hodgkin's disease and produce a 99 percent remission in patients with acute lymphocytic leukemia (Myers 1983). Global sales of these two drugs now exceed $180 million a year (Wilson 1992). Taxol, a compound from the Pacific Yew found in the last of North America's old-growth forests, has proven effective against ovarian and other cancers.




In the long run, forests left standing are of greater benefit than those cut and destroyed. The dollar value of natural ecological systems, of which forests make up a large part, in performing services for human society has been estimated at as much as $54 trillion, as seen in Chapter 1 ("Earth's Worth" section). Along with their role in flood prevention and climate regulation, forests provide fruits and flowers to be pollinated by wild insects and birds, and clear rivers as habitat for valuable salmon and trout fisheries (Stevens 1997b). The World Resources Institute in Washington, DC, has calculated that the loss of value from deforestation is four times as high as the value of the timber extracted and the depletion of soils, forests and fisheries amounted to an average reduction of 25 to 30 percent in potential economic growth (Stevens 1997b).


The ways in which forests function are only beginning to be understood. Great fig trees are dependent on tiny wasps to complete their reproduction, and fungi in the roots of trees play intrinsic roles in their survival. Pollinators are key to the health of forests, but for many species of trees and plants, only fragmentary information has been acquired about how they are pollinated and the conservation status of these pollinators. Understanding the interrelationships of plants and animals within these ecosystems is key to their preservation, yet forest ecology is in its infancy.


While logic would seem to mandate that such awesome and useful ecosystems be accorded great respect and legal protection, the opposite is true. They are being destroyed so rapidly by logging, dams, climatic changes caused by human activity, and pollution that the last pristine forests may soon be gone. Even minor alterations in their environments have interfered with their healthy functioning.


Cutting forests for financial gain or to resettle people from overpopulated cities provides developing countries with short-term solutions to problems and one-time profits. Neither the extremely important ecological roles that forests play, nor their value as species storehouses, are appreciated by the majority of the world's nations. The recent spate of massive landslides and floods after periods of heavy rains in countries around the world has, in most cases, been traced to logging that left hillsides and entire regions open to erosion. Millions of people have been left homeless around the world in recent years, and thousands have lost their lives to such floods. These floods may be only a prelude to far more serious and long-lasting consequences of forest destruction. Global warming will increase as forests vanish, especially with the cutting of old-growth trees, which have immense canopies for absorbing carbon dioxide and cooling the atmosphere. Higher temperatures have already brought droughts, increased desertification and caused rivers and streams to lose volume and even dry up. The loss of potential disease cures is another byproduct of destroying forests, and the destruction of these beautiful environments, with their multitude of life forms, may result in collapsed ecosystems that cannot be restored.

How have Forests benefited people

Provide fertile soil for good and fast growing of crops .
Provide enough oxygen for the survival of species by absorbing carbon dioxide and changing it to oxygen .
Absorbing carbon dioxide also reduce greenhouse effect , thus reducing global warming .
Forests give wood to manufacture furniture .
Forests produce food .

Sunday, August 3, 2008

Functions and Uses of Forests

Forests as watersheds
The bulk of the earth's rainfall is received by mountains, thus forming the headwaters of the land's water distribution channels. As a result, the mountain forests influence the quantity and quality of this precious freshwater resource. For example, forests are usually the best cover for safeguarding water quality from sediments and chemicals.

Flow of water from Forest catachment areas is complex, making generalizations difficult. However, there is evidence to suggest that cloud forests and some older natural forests can increase net water flow. Montane "cloud" or "fog" forests are special kinds of forests that scrape out moisture from the clouds or fog. This water extraction function is in addition to the vertical precipitation received by these forests. Having relatively low water use, these forests add to the water supply of a catchment.

In addition, forest cover can reduce the problem of flooding from many small, frequent storm events in headwater watersheds close to the forest area.


posted by Tan Bing Xiang