 Girdling the earth between Cancer and Capricorn lies a great belt of tropical forest. From the basins of the Amazon and Orinoco, it runs across the middle of Africa between the dry savannas and on to Southeast Asia and the islands of the Pacific. At its heart are the equatorial rainforests, the greatest celebration of life to evolve on earth. Above ground is a riot of vegetation and varied life. But the soil from which it stems is paradoxically poor. The secret of the forest's abundant growth lies in the unique way it recycles its nutrients. Decaying vegetation is rapidly broken down by the profusion of fungi, bacteria and insects that inhabit the forest floor. And just as swiftly, the organic matter is reabsorbed so efficiently that very little remains in the soil. No rain falls here than anywhere else on earth, yet the forest absorbs it like a giant sponge, turning sudden and violent onslaughts into a steady release of water. Its tangled roots holding back the soil, its streams and rivers running clean and clear. In their richness and diversity, the tropical forests are the most complex of all ecosystems, and still the least understood. But from them have come an astonishing number of our staple foods, essential medicines and industrial raw materials. How many more remain to be discovered, we can only guess, and we may never know. For now, after millions of years of evolution, the great forests are threatened with extinction. No one can say for sure how much has already been lost, but there's evidence that a fifth has been destroyed in this century, most of it in the last 20 years. If the rate of clearance continues to accelerate, another two-fifths could be destroyed by the year 2000. In 40 years, the tropical forests could virtually disappear. If they did, the result would be more than an ecological disaster. It would be catastrophic for millions of people who depend on them for their survival. Why then is it happening? In Southeast Asia, hardwood timber means foreign exchange, revenue desperately needed for development. Not every tree has value, but felling just one in 20 can damage up to half the surrounding forest. And is already 30 times what it was in 1950. If extraction rates continue to rise, most of their prime timber will be exhausted before the end of the century. Even so, the international timber trade accounts for only a fifth of the total forest clearance. The rest is being destroyed in the struggle for human survival. East Africa, where the tropical forest fringes out toward the dry savannas. The daily cutting of wood for fuel. In the foothills of the Himalayas, the same relentless attrition of woodland at the forest's margin. Nepal and Kenya, two countries caught in a predicament that affects close to half the world. Two billion people are dependent on wood for survival. Condemned to destroy it faster than nature can replace it. And as the forests recede, the back-breaking trek for fuel grows longer every year. For each family, just a few pounds of firewood a day. But worldwide, it means the loss every year of over 60,000 square miles of tree cover. Much of it from fragile arid lands and vulnerable upland watersheds. For these people, simply providing enough food is in itself a struggle. To be compelled to spend their days in the endless search for fuel is an added burden almost impossible to endure. And all for a few sticks of wood with a pitiful yield of energy. For the urban poor who have to pay for it, the growing scarcity is pushing it beyond their means. Whether they use charcoal or wood, providing for basic needs can cost a family up to 40% of its income. For the poor throughout the third world, the energy crisis is not about oil, but about wood. In the rainforest areas, it's not fuel that scares. It's land. Down the trails left by the logging companies have come the squatters, the landless poor. No room for them on the good farmland. No jobs for them in the towns. Desperate for somewhere to settle and grow food, but unaware of the infertility of rainforest soils. As a result, the practice of slash and burn agriculture has become the greatest single threat to the rainforest's survival. All the more tragic, because the destruction achieves so little. Burning the vegetation to get at the land gives it a deceptive injection of fertility, and for the first year or two, crops flourish. But without any further replenishment, the soil soon becomes exhausted. Yeels fall away year by year until crops fail altogether. The promised land, an illusion with no future. In Nepal, the same relentless pressure of population, but different consequences. For centuries, its people have farmed the fertile valley floors and terraced the lower slopes of the Himalayan foothills. But with the desperate need to bring more land under cultivation, there's been only one way to go. Now the terraces climb even the steepest slopes. The trees cleared for crops as well as fuel, while cattle and goats strip what's left of the vegetation. Roughly half the world's people live in areas where watersheds are inadequately protected. Where the pressure of growing numbers is destroying the tree cover that holds the soil. In Nepal, when the monsoon breaks, the consequences can be devastating. It can take just five years to strip fertile land down to bare rock. But with every monsoon, the damage spreads far beyond the hills, and rushing thick with silt on their way to swell the floods on the plains of India and Bangladesh. When the forces of nature run uncontrolled, national frontiers cease to have any meaning. The only reality is the appalling extent of human suffering and loss. The threat to the tropical forests. Every minute 10,000 trees fall victim to the overwhelming pressure of people's need for timber, fuel and farmland. As a result, natural habitats are being destroyed, vast areas of land degraded, and control over soil and water lost where it is most needed. At the root of the problem, too many people, and a chronic lack of alternative resources. The predicament of millions in the third world who are destroying tree cover not from choice, but of necessity. What then can be done to avoid the impending disaster? In Nepal, the beginning of restoration. Replanting denuded slopes with a quick-growing species of pine. A pilot project aimed at preventing further erosion in a district close to Kathmandu. Trees to stabilize the soil. And to control the runoff of water, check dams. A series of simply constructed walls to plug washed out gullies and ravines. It's a start, but the task is formidable. This is one of the poorest and most inaccessible regions on Earth. To multiply these measures along the entire Himalayan front would take years of effort, and international aid on a massive scale. And even then, it would be futile unless at the same time, the destructive ways of the past can be changed. Take it out. Remaining woodland, a new plantations need protecting, but government can't provide the manpower. It's the farmers themselves who are being persuaded to do it, through the local village councils. At this meeting, they're discussing what finds the guards should impose. What's the name of the plantations? I'll give you the address. I'll give you 10 rupees for 5 rupees. Is everything alright? If you're not a farmer, I'll give you 10 rupees. If you want to keep the plantations, you can keep one. It's asking a lot of poor farmers to give up their traditional rights. But they will if they can gain in other ways. Here in Nepal, they're beginning to get help from government. Fertilizers, better seed, cheap credit, access to markets. The chance at last to get more out of their land. And what they must grow is not just food, but fuel. In Kenya, this has been government policy for a number of years. They're gradually overcoming the farmer's reluctance to grow trees by providing them with varieties of eucalyptus that take only 7 years to mature. Kenya's aim is to turn chronic shortage into self-sufficiency by the year 2000. Not just in the rural areas, but in the fast-growing towns. Here on the outskirts of Nairobi, the guarantee of regular supplies. For the market price of a single bundle, they can get a permit to gather a load of plantation trimmings every day for a month. The plantation is one of many that are being established throughout the country. The logs are for sale in the city. The trimmings a bonus for the people who live nearby. It's still the same backbreaking load, but it's only a short walk home. But for the government, the solving of the fuel-wood crisis is a daunting commitment. 50 million trees to be planted every year, and that's just Kenya. Worldwide, it would require investment on a scale the developing countries couldn't hope to make, unaided. Growing trees instead of destroying forests is a simple enough idea. The problems are always finance and people's resistance to change. But when these are overcome, it can work a remarkable transformation. A pulp mill on the coast of Mindanao. What makes it unique is its reliance on wood supplied by small independent tree farmers. It's a scheme developed by the paper industries corporation of the Philippines. On signing an agreement to grow trees for the mill, they're given access to technical assistance and a bank loan, repayable only when their plantations start to produce an income. Many of the tree farmers came here as squatters and found only despair. But now they have a stake in the future. Instead of a life of poverty and bare subsistence, they can afford to invest in their land, restore its fertility and produce a surplus for market. And after only seven years, their first trees are ready for harvesting. A commercial enterprise in the Philippines has shown what can be achieved with foresight and imagination. For the company, a valuable addition to its timber supplies. For the settlers, a secure and steady income. And for the surrounding forest, a reprieve. Here at least in one small corner of Mindanao, the threat from slash and burn agriculture has been removed, making forest land productive. In Malaysia, the approach is even more radical. Faced with a rapid decline in her reserves of hardwood timber, the urgent need was to develop an alternative source of revenue. The plan they came up with was to retain over half the remaining rainforest, but clear the rest completely, replacing it with tree crops native to the forest, mainly palm oil and rubber. At the same time, they're solving a chronic social problem, providing work and housing for thousands of poor, landless families. From the more backward rural areas. Within two or three years of arrival, they're working the plantations for themselves and earning an enviable income. Twenty-five years of experience have proved that the plan is environmentally sound. The plantations function like natural forest in holding the soil and regulating the release of rainwater. By the end of 1980, they were over 740,000 acres of oil palm in production and nearly 500,000 of rubber. Forest and people transformed together. Thousands of families, given a new economic status and access for the first time to the amenities of a thriving modern community. Time for recreation. Money to spend. And a revolution in the quality of life that comes with electricity and clean piped water, health clinics, libraries and schools. Malaysia's land development scheme is a unique achievement and offers an important lesson. Selected areas of forest can be sacrificed and successfully converted to more intensive use, but it takes rare expertise and ample resources to do it. The Trans-Amazonia Highway cut through 2,000 miles of Brazil's virgin forest. To some, it was the symbol of a nation laying claim at last to its vast uncharted interior. To others, it signaled only destruction, the first assault on the last great reserve of tropical wilderness. The scale of the clearances that followed seemed to confirm their worst fears. But the fate of Amazonia is still an open question. Its area is so vast that most of it remains undisturbed. Undisturbed. But for how long? This is the world's greatest untapped reserve of tropical timber. And as the hardwood resources of Asia and Africa are depleted, the pressures on Amazonia are bound to grow. Must its exploitation lead inevitably to its destruction? Or can the rival claims of conservation and development be reconciled? The Brazilian government is engaged in a major program of research to find out. Their studies are concentrated on one small area, but from it will come evidence valid for the whole Amazon basin and the answer to a fundamental question. How much timber can be taken out at any one time without destroying the forest's power to recover and go on yielding indefinitely? 65. On each of a series of trial plots, they select a different number of trees for felling. By varying the intensity of logging, they will be able to compare the effects over a number of years. In an area logged two years previously, an investigation of the forest's natural powers of recovery to discover what species are regenerating. This is a good species, isn't it? This is good. It may be that nature needs to be assisted by additional planting, so that too is being investigated, using seeds gathered from some of the finest specimens in the forest and reared in a nursery. I'm going to mix these together. Where were they collected? Results from the trials and experiments now underway cannot be expected quickly, but they're the key to a unique opportunity, a chance to plan the future exploitation of Amazonia's hardwood resources by working with nature, rather than against it. Meanwhile, elsewhere in Brazil, the growing demand for other forest products is being met by a different strategy. Forests where none grew before. Already, a total of 25,000 square miles of unused marginal land have been planted, and plans are in hand to more than double the area. Brazil's commercial plantation program is the largest in the tropics, already providing two-thirds of her needs for pulp, lumber, and fuelwood. These plantations are, in effect, highly productive industrial wood farms. Yields are up to 20 times those of an equivalent area of natural forest. If only financial resources on this scale could be made available throughout the tropics, the pressures on the natural forest would be eased dramatically, reducing the pressures. Everywhere, this is the crux of the issue. For the one thing we need, this is the crux of the issue. For the one thing we cannot do is to recreate the forests themselves, rebuild what nature evolved over millions of years, a forest reserve in which the only intruders are scientists. So much remains to be discovered. To lose this rich storehouse of plants and animals, this vast laboratory of living processes might be to deprive ourselves not just of knowledge and understanding, but of resources vital to our future well-being. In every distinctive environment, zones like this need to be established and totally protected against any disturbance. Area is large enough for all forms of life to continue to flourish. Enlightened governments have already begun to build this ultimate line of defense, this refuge of last resort. In less than 50 years, it could be all that's left. The tide of destruction continues to advance. But even now, it's not too late to turn it back. What's needed is a bold and urgent attack on the root causes of the problem, a concerted response from the whole world community to help raise the level of existence among the poor of the third world. Only when land is used far more productively and when energy can be provided cheaply from alternative sources will the threat to the tropical forests be finally overcome.