Man’s Dominant Raw Material : THE VANISHING FORESTS : Need for Wood Forestalled Conservation

When the Carthaginian explorer Hanno sailed down the Atlantic Coast of Africa about 520 BC, he recorded seeing great fires inland for days on end, accompanied at night by the terrifying sounds of drums, gongs and wind instruments.

“Although Hanno failed to comprehend their nature, these fires must have been due to the annual ‘burning of the bush’ to beat back the forest and provide land for agriculture and grazing,” according to the late botanist Wendell H. Camp. “Thus we have evidence that for at least 2 1/2 millennia--and how much longer we shall never know--great forest tracts in Africa have probably been regularly despoiled by fires purposely set by man, much as they are today.”

Fires and other destructive human activities contributed significantly to the desertification of the Sahel Zone, the coast of which Hanno skirted, long before the recent droughts, population pressures and overgrazing usually cited as the culprits.

So it goes around the world and through the ages. Just about everywhere humans have lived they have been hard on forests. This is true of migratory bands of primitive hunters and gatherers presumed to be in tune with nature, and it is even truer of today’s sophisticated, supposedly enlightened industrial civilizations.

Cutting trees without much regard for their replacement has been the rule throughout recorded history. Not until the late 18th Century in Europe and the mid-20th Century in the United States did the practice of cultivating and restocking forests take hold. And this progressive step has largely been offset by the advent of modern machines able to mow down forests quickly and industrial processes that poison them inadvertently.

If the world ever ran out of forests, it would be no small matter, given the central role wood has occupied in human affairs. Without the warmth and shelter provided by wood, humans could not have survived and flourished in northern latitudes. Wood has been the dominant construction and industrial raw material for nearly all of recorded history. The production of mineral wealth through mining and metallurgy has depended on wood. And wooden ships dominated the seas for several thousand years, permitting Europe to colonize much of the world.

Five causes of deforestation that have been pervasive around the world and through the ages, and that continue today, are the use and abuse of forests to farm, graze livestock, provide timber, supply firewood and wage war.

Farming

Long before they developed tools capable of clearing forests, primitive people used fire to thin them out and beat them back in an effort to improve the yield of food and fodder.

Historians say that people have set fires in forests from time immemorial to clear away underbrush and make it easier to find nuts on the ground and dig for edible roots and tubers. Fire also has been used to improve the harvest of berries and to encourage willows and hazels to sprout and produce pliable shoots for basket weaving.

Hunters have used fire to open up dense forests that conceal animal and human enemies, thereby improving visibility and making hunting safer. They have set fires both to drive game out of the woods into ambush and to create grassy clearings to which game is attracted by succulent new forage and the salt content of ashes.

Some ecologists maintain that centuries of burning by primitive people created and maintained such great grasslands as the savannas of Africa, the steppes of Eastern Europe and Russia, and the pampas of Argentina. Some think American Plains Indians enlarged the Great Plains by firing forests to expand the range of the buffalo. They point to the fact that northwestern Illinois and southwestern Wisconsin were mostly prairie when first visited by white explorers but reverted to forest when the Indians were driven out.

Avoiding Swinging an Ax

Forest-dwelling American Indians used fire to clear plots for farming. First they gouged a strip around the trunk of each tree, preventing the sap from flowing and mortally wounding the tree. Then they planted corn under the leafless tree, later cutting it down and burning it to make a better field. White settlers followed the Indian practice, girdling trees to spare themselves the backbreaking toil of swinging an ax day after day.

Although the Indians who farmed clearings in the dense forest that blanketed the Eastern United States generally lay lightly on the land, forest farmers in many other parts of the world were much more destructive. Take Hawaii, for instance. The Polynesians who arrived about AD 700 slashed and burned large swatches of lowland forest (especially between 1300 and 1700, when their numbers burgeoned) to plant crops and provide fodder for their pigs and thatch for their houses.

Contrary to the common assumption that the Polynesians’ impact was minimal, their forest clearing caused widespread soil erosion. And in combination with hunting and the introduction of pigs, chickens, dogs and--inadvertently--rats, deforestation had a devastating effect on the ecology, wiping out a third to a half of the known species of snails and birds by the time the Europeans arrived in 1778.

Humans suffer with other species when fragile rain forest environments are overtaxed. Some scholars trace the collapse of the Mayan civilization in Central America about AD 900 to population pressures that caused overcropping, erosion and a decline in the land’s productivity.

Soils in the Tropics

Tropical moist forests are generally less productive when cleared for farms and pastures than temperate forests. With most nutrients tied up in the vegetation, tropical forest soils are generally unsuitable for continued crop farming. But they will support crops for several years when enriched by the ashes of trees that are felled and burned. If the plots are then allowed to lie fallow and regain fertility for 20 years or so, they can again grow crops.

Shifting slash-and-burn cultivation is environmentally sustainable when there are limited numbers of people and they have room to move from place to place, leaving the wounded forest behind for time and nature to heal. But when populations grow too dense and the land is overused, the forest loses its recuperative capacity, often degenerating into scrub.

That’s what is happening today in many Third World countries, as landless peasants desperately attempt to farm forest soils permanently. Environmentalists say farmers are the leading cause of tropical deforestation, more so than timber loggers, cattle grazers or firewood gatherers. “Amounting to roughly one in 20 of all people on Earth, these farmers represent the most pervasive form of environmental degradation overtaking the tropics,” according to Norman Myers, author of “The Primary Source: Tropical Forests and Our Future.”

To be fair, most of these forest farmers have little choice. In tropical countries, wealthy people typically own and occupy most of the best land--the river valleys and the gentle slopes. This relegates peasants to small subsistence plots and marginal areas. As single-crop plantations and cattle ranches have expanded in recent decades to meet growing demand by the elite and exports to rich countries, millions of tenant farmers have been squeezed out, joining an army of landless seasonal laborers. Many head for the only “free” land left--the forest.

Taking the Easier Path

Just as the U.S. government encouraged white settlers to take over the American frontier from the Indians, the current governments of Brazil, Indonesia and some other developing countries seek to secure national sovereignty over remote forests by colonizing them. They have found it easier to hand out land occupied by forest tribes who can’t stand up to modern weapons than to redistribute already cultivated, generally more suitable, farmland owned by the wealthy elite.

“Rain forests are often used by governments as safety valves to defuse pressure for land reform,” according to Catherine Caufield, author of “In the Rainforest.” “The true cause of agricultural settlement in rainforests is often inequitable land distribution rather than simple overpopulation.”

There’s no question that tropical deforestation began long before overpopulation became a factor. Indeed, the large areas of the Caribbean and North, Central and South America that Europeans deforested in the 16th to 19th centuries were so underpopulated that slaves were brought in from Africa to provide essential labor.

New World forests disappeared in favor of cotton, sugar, coffee, rice and banana plantations. In West Africa, it was cotton and peanuts. In northeastern India, it was tea. And in Burma, the British transformed the forested Irrawaddy Delta into the world’s greatest rice-exporting area.

Shift in Cotton Production

Deforestation accelerated in the 19th Century along with the spread of imperialism and the expanding world market. The U.S. Civil War, by cutting off Southern cotton exports and increasing the price of cotton on the world market, prompted much deforestation in western India.

“The rapid expansion of monocrop commodity production in the 19th and early 20th centuries in the world’s colonies and dependencies was one of the primary reasons for today’s dangerous imbalance between the First World and Third World,” according to historians Richard P. Tucker and John F. Richards, co-editors of “Global Deforestation and the 19th Century World Economy.”

A case can be made, for instance, that Brazil’s northeast is economically depressed because much of it was deforested by the end of the 19th Century for sugar and coffee. Similarly, one of the reasons Haiti is the most deforested (and poorest) country in the Western Hemisphere is that its forests fell to sugar, coffee and cotton.

Although no longer a colonial dependency, Hawaii has followed the typical Third World development pattern, losing its forests to sugar, coffee and pineapple fields, many of which have subsequently been abandoned with rising labor costs and glutted world markets. Hawaiian ecologist Frederick R. Warshauer fumes: “Hawaii is a colony of the United States. It’s locked into an import-export economy that is harmful to both the environment and the state’s economy.”

Export-Oriented Agriculture

Of course, the continental United States also practices export-oriented agriculture, much of it also at the expense of forests, to produce wheat, corn, rice, cotton, soybeans and other crops mainly for sale to other affluent countries that can afford to buy them rather than to hungry countries that can’t.

More than 5 million acres of forest in the lower Mississippi River Valley from southern Missouri to southern Louisiana have been cleared since 1950. The major replacement has been soybeans, much in demand here and in Europe as a livestock and poultry feed.

The federal government has facilitated the deforestation with drainage and dredging projects to dry out the low-lying, seasonally flooded land, tax deductions for land clearing and drainage expenses, low-interest loans that encourage farmers to expand operations and subsidized crop insurance to reduce the risk.

Environmentalists oppose the conversion of these so-called bottomland hardwood forests as increasing marginal farmland at the expense of excellent wetland and wildlife habitat. And even some government officials agree.

“In the long haul, it was not a good idea,” says Stanley L. Krugman, director of timber management research for the U.S. Forest Service. “Serious floods and soil loss have resulted. A lot of soybean fields have reverted to flood plain, while the soil has washed away into the Gulf (of Mexico).”

Wheat production also has been expanded at the expense of trees, again with government encouragement. In the early 1970s, when the Soviet Union ran short of grain and made its first large purchase of U.S. wheat, Agriculture Secretary Earl Butz exhorted farmers to plant their land from “fence row to fence row” to maximize production. Forgetting the hard lesson of the past, thousands made room for more wheat and big new farm machinery by tearing out rows of trees, many of them planted as windbreaks after the 1930s Dust Bowl. As a result, parched topsoil once again was gone with the wind.

Grazing

Herders are hard on forests, too. They have a tradition of hacking down trees to provide fodder for their hungry cattle, sheep and goats, and of starting forest fires to replace trees and shrubs with tender young sprouts and grass.

Where they spare the woods but pasture livestock in it, their heavy-hooved cattle trample small trees, expose tree roots to the extremes of heat and cold, cave in stream banks and accelerate soil erosion. Sheep eat grass and other plants down to the roots. And goats, preferring to browse on shrubs and trees, pick them clean when given the chance.

“Goats made permanent the deforestation of thousands of square miles of Mediterranean hillsides by eating every seedling tree that ventured to show its head, until there were no more left,” University of Denver historian J. Donald Hughes says in “Ecology in Ancient Civilizations.”

When Europeans colonized the New World, they took with them their destructive propensity to allow herds to overgraze. As a result, large areas became as treeless as the Mediterranean hillsides they had left behind.

Today, pastoralists and their herds are on the defensive in many Third World regions, as expanding plantation agriculture squeezes them onto smaller and less favorable grazing ranges. Reflecting the ability of sheep and goats to get along on less favorable forage than cattle, African herders have responded by increasing their sheep and goat herds three times faster than the cattle population since 1970. Given goats’ propensity to devour tree shoots and seedlings, this has helped increase the continent’s deforestation rate.

Ranchers Move On

In tropical rain forests, pasturing cattle not only damages the forest but, like farming, is usually unsustainable. As environmentalist Myers points out, “Formerly forested soils quickly become exhausted of nutrients, and pastures feature poorer and poorer grass unless they receive ever greater amounts of fertilizer.” Toxic weeds invade. Soil erodes. And ranchers move on to another patch of forest.

Such “shifting ranching” helps Third World countries earn foreign exchange when the beef is exported. But in Central America, where cattle raising remains the leading cause of deforestation, beef exports and revenues have fallen sharply since 1979. The drop reflects revolutionary Nicaragua’s shift from raising cattle for export to growing food crops for domestic consumption; the fighting there and in El Salvador, and declining beef consumption in the United States.

The United States has its own huge cattle population, and it has been doing its share of deforestation for their benefit. In the Southwest, the Forest Service and the Bureau of Land Management cleared several million acres of pinon pine and juniper woodlands on federal land during the 1950s, ‘60s and ‘70s in an attempt to increase grass and water for cattle grazing.

Dragging Anchor Chain

The usual method was for two bulldozers moving abreast to drag a ship’s anchor chain between them, uprooting trees in their path. But chaining demolished countless Indian archeological sites, undermined the self-employment of Indians who collected pinon pine nuts for sale and helped radicalize outraged Paiutes and Soshones. Chaining also was ineffective in increasing water yield or grazing forage in many areas. And because the chain passed over seedlings and saplings, allowing them to spring back and survive, it didn’t even get rid of the woodlands permanently.

“In some places, clearing increased range productivity and the impact on other things was low enough” to justify chaining, says R. Max Peterson, who retired as chief of the Forest Service earlier this year. “In other areas, removing juniper-pinon didn’t make environmental or economic sense. In hindsight, we had twice as much juniper-pinon clearance as we should have.”

Chaining continues today, but on a vastly reduced scale. The Bureau of Land Management in Utah, for one, says it is chaining much smaller blocks, following natural contours more often, and leaving islands of unchained woodlands to protect wildlife.

Timber

Humans have been logging forests to provide timber for thousands of years.

In ancient Greece, after deforestation made wood scarce, large stone and brick buildings still needed wooden beams, rafters, doors and roof shingles. Even the stone Gothic cathedrals of the Middle Ages were heavily dependent on wood scaffolding, cranes and windlasses to raise the stones.

London and Paris were wooden cities until deforestation forced substitution by stone, brick and tile. When London was rebuilt after the fire of 1666 consumed 12,000 houses, wood was so scarce it had to be imported from Norway and the Baltic region.

The pines of Muskegon, Mich., built Chicago twice--before and after the great fire of 1871. And forests as far south as Big Sur were logged to provide lumber to rebuild San Francisco after the 1906 earthquake and fire.

Construction in timber-rich America was often wasteful. Log cabins used whole logs, which saved sawing but wasted wood. Gingerbread Victorian houses with elaborate, superfluous ornamentation used wood extravagantly, to the delight of lumber merchants who distributed architectural plans promoting the style. Less-wasteful modern designs reflect not only changing public tastes but the declining abundance of lumber.

Wood-short societies have long looked to better-forested neighbors. Ancient Egypt, Israel and Babylonia all exploited the forests of Lebanon and Syria.

The Egyptian Pharaohs imported shiploads of Lebanon’s cedars to build their palaces, temples and tombs. King Solomon exchanged wheat and olive oil for the Lebanese cedars that went into the construction of his temple in Jerusalem.

Burden Goes to Canada

Nowadays, the United States gets a nearly third of its softwood lumber and three-fifths of its newsprint, among other forest products, from Canada. The lumber imports are controversial because they reduce U.S. industry profits and employment. But they also help spare U.S. forests from further depletion.

The search for timber has spurred exploration, conquest and colonization. When the cedar, pine and cypress that covered their home mountains in Lebanon and Syria grew scarce, the Phoenicians set sail to exploit the forests of Cyprus and Crete. After deforesting their own country, the Greeks colonized well-wooded southern Italy and Sicily. And when the Romans, in turn, ran low on wood, they depleted the forests of Morocco, Algeria and Tunisia.

More recently, another island nation, Japan, plundered the forests of Taiwan, Korea and Manchuria in turn. Since the end of World War II, which put a stop to their taking timber by force, the Japanese have been buying what they need from Southeast Asia, the United States and other suppliers.

The United States, with vast forests of its own, hasn’t needed other nations’ forests to maintain strategic superiority. But it has never been averse to making money from them. After taking over the Philippines in 1899, the United States introduced modern logging, clear-cutting virgin forests and introducing dipterocarp lumber, mistakenly called “Philippine mahogany,” to the world market.

Illegal Logging Rampant

Deforestation of the Philippines has accelerated since the end of World War II. Presidential decrees have transformed forests used communally by tribal groups for thousands of years into government property. Then logging companies have mowed them down. Illegal logging is also rampant. As a result, forest cover has dropped from 70% of the Philippines’ land area in 1900 to about 40% today.

Exploiting public forests for private profit is nothing new, of course. It has been going on at least since Greek and Roman times. In some cases, governments have granted or sold timber rights to individuals. In others, government officials have personally profited.

One all-but-forgotten case involves Hawaiian kings and the Yankee ship captains who as early as 1790 saw an opportunity to profit from the islands’ extensive stands of sandalwood trees, whose fragrant oily heartwood was then in great demand in China and India.

The captains tempted King Kamehameha and his successors to exploit the sandalwood in exchange for such items as an $800 looking glass and $10,000 brass cannon. The kings also wanted some of the white man’s sailing ships and paid for them with an equal or double amount of sandalwood.

By 1836, the sandalwood was exhausted. Slow-growing and unresponsive to nursery propagation, sandalwood exists today only in scattered remnants, a reminder of the shortsightedness of opportunistically mining forests for export earnings with no thought to sustained yield.

Conscripting commoners to find, cut and haul timber wasn’t limited to Hawaii. The Chinese emperors of old used to burn the palaces of their predecessors, then order fabulous replacements with proclamations mobilizing peasants into deforestation crews.

Mechanization of timber harvesting makes logging less labor-intensive nowadays. But it also increases its destructiveness. Consider the situation in California. When the horses and oxen that used to skid logs from the woods to small sawmills were replaced by steam locomotives, and later diesels, clear-cutting of extensive areas was facilitated. And sparks from the locomotives and the application of brakes set many fires.

Steam power freed sawmills from dependence on manual whipsawing or locations near flowing water. In the San Francisco Bay area, steam power hastened the clear-cutting of a redwood forest that covered 25 square miles of the Oakland Hills.

“These mills were very efficient and very thorough,” historian Sherwood D. Burgess has recounted. “By 1860 only a sea of stumps marked the site of the East Bay redwoods. In tune with the unsentimental economy of the day, not a single original redwood was saved for posterity.”

A Loss of Accuracy

When the gasoline-powered chain saw replaced the backbreaking two-man crosscut saw, it increased production, but it also caused more waste in the woods. “The chain saw traded volume for accuracy,” says Dean Huber, program manager for forest products utilization for the Forest Service in San Francisco. “When it took two men all day to cut a single log, they made the cut carefully. When one guy could make the same cut in 20 minutes, he cut less carefully and made up for mistakes by cutting more trees.”

The heavy, efficient machinery developed since World War II cuts down trees and gets out logs even faster. But it also leaves landscapes looking like targets of saturation bombing, as bulldozers gouge and loosen the soil, burying slash and debris. Carelessly cut logging roads cause hillsides to wash away.

“Technology has overrun the forest’s ability to withstand what man might want to do with it,” says Zane G. Smith Jr., the Forest Service’s Pacific Southwest regional forester. “We can do anything we want to, including wrecking the whole business overnight.”

Firewood

Humans have gathered around wood fires since the earliest times to keep warm, cook their meals, repel wild animals and insects, relieve the darkness and enjoy one another’s company.

Today, an estimated 60% of all the wood cut in the world is burned as fuel. Firewood is in desperately short supply, and firewood gathering is a major cause of deforestation in many Third World regions. The shortage is particularly acute in areas that were lightly wooded to begin with, such as the semi-arid savannas of Africa, and where regrowth is slow, as in the Himalayas of Asia and the Andes of South America.

“Nearly 1.5 billion people in 63 countries, or about 60% of the people who depend on fuel wood as their principal source of energy for cooking and heating, are cutting wood faster than it can grow back,” the World Resources Institute and the International Institute for Environment and Development say in their joint study, “World Resources 1986.” The result is a firewood deficit that the two policy research organizations expect will double by the year 2000.

Third World population pressures usually get the blame for the firewood crisis. The contributory role of industry is less widely acknowledged. Yet many countries, including Australia, India and Brazil, still depend on wood-derived charcoal for their iron and steel industry. And many countries consume enormous quantities of firewood to refine sugar, preserve fish and cure tea and tobacco.

Smokers Elsewhere Benefit

In east and central Africa, it typically takes two acres of trees to cure the tobacco grown on one acre, says John Spears, senior forestry adviser to the World Bank. “Most of the tobacco is exported” for the benefit of smokers elsewhere, he says, while local residents suffer the consequences of the desiccation, soil erosion and declining productivity that follow deforestation.

Firewood shortages are impeding the industrial development of many nations that lack adequate alternate sources of energy. And the deforestation overtaking these countries is a replay of what happened when many already developed countries went through the industrialization process. Some of these countries have recovered fairly well from past fuel wood crises, while others have never been the same.

Mining and metallurgy have been major causes of deforestation for thousands of years. In the ancient Mediterranean and Middle East, iron, copper, tin and lead miners not only used timbers in great numbers to brace underground tunnel ceilings and walls, but they set wood fires underground to crack resistant rocks.

Even more wood was consumed extracting metals from the rocks brought to the surface. Humans discovered smelting by observing how forest fires melted mineral outcrops naturally. They discovered charcoal when the black material left over from previous fires burned with a higher, more-even heat than firewood, and with much less smoke and flame. Putting the two discoveries together, early societies were soon burning mountains of charcoal to smelt mountains of metallic ore.

Boromir Jordan, professor of classics at UC Santa Barbara, and ecological historian John Perlin trace the fall of the once-flourishing Mycenaean civilization in about 1150 BC to the deforestation of Cyprus and Aegean islands that had supplied the copper needed for this bronze-age civilization. “Lacking adequate stores of bronze to make arrowheads, spearheads and sword blades, the Mycenaean kingdoms fell to the blows dealt by their better armed foes,” they say.

Smelting required such enormous stretches of forest to supply the charcoal needed for the smelting process that Europeans generally found it cheaper to move the ore to the forest than vice versa. So the manufacture of iron, copper, tin and lead was typically conducted by small establishments scattered through the forest that moved when the local supply of wood gave out.

The invention of the reverberatory furnace in the 1680s made it possible to switch from charcoal to coal to smelt nonferrous ores. But the production of iron and steel remained dependent on charcoal as a heat and carbon source until the introduction of coke distilled from coal in 1709 and the invention of the puddling process in 1784. After that, England’s iron industry moved from the decimated oak forests of the south to the coal fields of the north.

On the Continent and in the United States, where the shortage of wood was less acute, it wasn’t until well into the 19th Century that smelting with coke derived from coal became widespread. Charcoal was used to produce all U.S. pig iron until 1832, and coal did not overtake wood until 1887. The last charcoal blast furnace in this country shut down only in 1945.

In Nevada, the silver mining boom of the 1860s and 1870s consumed an estimated 750,000 acres of pinon pine woodlands to supply the immense quantities of wood needed for mine pit props, fuel wood and charcoal. According to historian John Richards: “So voracious were the charcoal kilns . . . that the kilns at Eureka alone consumed the produce of 50 acres of pinon per day. From every mining center, a deforested zone radiated outward as much as 50 miles.”

Fewer American forests have died to supply fuel wood since its use has been eclipsed by other energy sources. But these alternatives have been hard on forests, too.

Appalachian Landscapes

Underground coal mining, with its pit props, surface facilities, waste piles and land subsidence, has had a major impact on once-forested hillsides in the Appalachians. And strip mining has taken an even greater toll, leaving former forests looking like desolate lunar landscapes, the topsoil eroded away and runoff of toxic metals and sulfuric acid discouraging reforestation. Unreclaimed coal-stripped land, most of it originally forested, occupies an area larger than Rhode Island.

Insatiable demand for electricity leads coal- and oil-burning power plants to spew out air pollutants that damage forests downwind. It also leads to forests being inundated behind dams. When Canada built the Mica Dam on the Columbia River in the early 1970s, it drowned enough trees to supply a pulp mill for 30 years because it didn’t want to take the time to harvest the trees beforehand.

And now firewood itself is making a comeback, both for home heating and to generate electricity. What’s different this time is that U.S. forests contain only a fifth as much timber as before the first Industrial Revolution. And this raises the question: Can they withstand a second?

Warfare

Military preparations and warfare have contributed significantly to deforestation around the world. And the toll continues.

In the days of wooden sailing ships, many a forest disappeared into a naval fleet, and many a fleet disappeared in battle. As the French historian Fernand Braudel pointed out, “Every fleet, in no matter what country, required for its construction the destruction of enormous expanses of forest.”

Robert G. Albion, a Princeton historian whose 1926 study, “Forests and Sea Power: The Timber Problem of the Royal Navy 1652-1862,” remains the definitive work on the subject, drew a parallel between the strategic importance of ship timbers in centuries past and the 20th-Century oil situation: “Oak, like oil today, was a natural product very abundant at the outset, but liable to ultimate exhaustion. . . . For want of an adequate domestic supply, nations sought colonies and exerted diplomatic pressure in those days for ship timber as they do now for oil.”

Access to forests spelled the difference between political ascendancy and decline. “Macedonia, an insignificant backwater country on the fringes of the Greek world until the 5th century BC, became the immensely rich and powerful central power of the world when the Greeks exhausted their supplies of wood and came to depend on Macedonia’s forests,” according to Jordan, the classics professor, and Perlin, the ecological historian. “The Macedonians soon translated their wealth into political and military power resulting in the conquest by Alexander the Great of nearly the entire known world, from Egypt to India.”

Similarly, the center of Italian civilization shifted during the declining years of the Roman Empire from deforested central and southern Italy to still well-wooded northern Italy. Much later, during the Renaissance, northern Italy exhausted its forests and allowed its hillsides to erode away, and ascendancy moved northward once again.

Even the thick forests of central and northern Europe fell in their turn. England and France, the principal northern European powers, engaged in so many maritime wars and so depleted their own forest resources that both conducted a worldwide search for ship timbers from the mid-17th to mid-19th centuries.

Their ships became international floating forests. The typical 74-gun English man-of-war contained the wood from 2,300 oaks obtained from 44 acres of English or Irish woodland. It had a mainmast of white pine from Maine, a topmast of fir from the Ukraine, spruce spars from Norway and cabins of Caribbean mahogany or Indian teak. Tar, pitch, resins, varnish and other naval stores from American Southern pines sealed joints and retarded rot.

In those days before the use of creosote and other wood preservatives, marine borers from without and fungous dry rot from within caused ships to decay quickly and have an average life of only 15 years. Masts usually had to be replaced after 12 years when their resin dried up and deprived them of strength and resilience.

The English prized the white pines in New England’s virgin forests for their size (some were 200 feet tall with trunks nine feet across), straightness, strength, resilience and durability. Representatives of the Royal Navy marked the best of the white pines in the name of the king and prohibited the colonists from felling trees the navy would someday need. This conflicted with the colonists’ desire to exploit the forests themselves and provided one of the grievances that led to the American Revolution.

If shipbuilding and naval warfare have been hard on forests, land and air warfare have been even more devastating. For one thing, firing forests has long been a potent weapon of war. During the U.S. Civil War, for instance, fires set willfully or accidentally in battles and by marching troops, as well as by non-military vandals and arsonists, burned extensive areas of forest in the South.

Some forests have been burned several times. One such is the pine forest in the Landes region of southwestern France. In 407 AD, invading Vandals razed villages, dispersed the population and set fire to the forest. This destroyed the cover of a vast sandy area. With the trees gone, winds sweeping in from the Atlantic Ocean piled the beach sands into dunes. The dunes rolled inland, choking streams and creating malarial marshes.

The forest has been damaged several times since then, most recently in World War II when incendiary bombs started fires that destroyed half a million acres.

Devastation From Agent Orange

The most devastating deforestation in warfare probably took place in Vietnam during the 1960s and early 1970s. In an attempt to deny ground cover and crops to their Vietnamese enemies and to break their spirit, American forces used bulldozers, explosives, napalm and 19 million gallons of Agent Orange and other herbicides to defoliate and destroy forests, rubber plantations, farm fields and other areas of what had been a beautiful, verdant countryside.

The defoliation campaign constituted the “deliberate destruction of the environment as a military tactic on a scale never before seen in the history of warfare,” the Swiss-based International Union for Conservation of Nature and Natural Resources concluded in a 1985 study.

According to that study, the forests have not recovered, and even trees that survived must be harvested and sawn with extreme care because many are riddled with shell fragments. Wildlife has not returned, the productivity of cropland and fisheries remains depressed, one-third of the country is now considered wasteland, and there has been a great increase in toxin-related disease and cancer.

Less widespread, but still very real, destruction continues elsewhere. In El Salvador, U.S.-supported government forces make a practice of cutting down fruit trees and killing livestock in areas in which local peasants support anti-government guerrillas. Meanwhile, bombing raids cause both deliberate and inadvertent damage to forests.

The situation in nearby Nicaragua is mixed. On the one hand, raids by U.S.-backed rebels have prompted ranchers to flee border areas with their cattle, allowing forests to regenerate. On the other hand, farmers displaced by the fighting have turned to slash-and-burn agriculture on forested hillsides. And contra -started forest fires and attacks on reforestation crews have forced the Sandinista government to suspend reforestation efforts.

The Price of Progress

Industrialization has both relieved and intensified pressure on the world’s forests. In developed countries, industrialization has permitted the substitution of metals and fossil fuels for wood in many applications. But in developing countries, the rapid population increases and widening economic and social inequalities long associated with early industrialization have multiplied exploitation of forests for farmland and firewood.

No area of the world better illustrates the price of progress than the West African Sahel, that semiarid sub-Saharan region that stretches eastward from the Atlantic Ocean through Senegal and Mauritania into Mali.

Pre-industrial damage to forests in the Western Sahel was extensive. By burning the bush to make tender, green forage available to wildlife and livestock, primitive hunters and herders turned many forests into grasslands, after which the grasslands degenerated into desert.

When they got guns from European traders in payment for slaves, Moorish herders virtually eradicated the wild carnivores that had preyed on livestock entering forests. This permitted herds to swell and chomp through the woods.

But the most destructive development has involved tapping the once-extensive acacia forests in the Western Sahel for gum arabic. Long prized as a thickener and stabilizer in the manufacture of printing inks, pharmaceuticals, adhesives and other products, gum arabic is obtained by peeling pieces of bark from the acacia tree and then collecting the gum that oozes from the wounds.

Acacia Forests Die Out

“The more stressed the tree, the greater the yield of gum”--and the greater the tree’s susceptibility to drought and disease, the National Research Council notes in a 1984 study.

Destructive tapping by the Dutch as early as 1448, and later by the French and English, effectively destroyed inland acacia forests by the turn of the 20th Century. Exploitation since then has finished off the acacia forest that used to run the entire 400-mile length of Mauritania’s now desert coast.

Scattered acacia trees have survived, mostly in and near farm fields where their usefulness in fixing atmospheric nitrogen and fertilizing the soil has long proved their worth. But in recent decades a switch from subsistence farming for local consumption to mechanized farming for export doomed many of these trees as well.

Peanut farming in Senegal typifies the trend. As recounted by the U.N. Food and Agricultural Organization: “The land was originally worked by hand, left fallow every few years, and benefited from the fertilizing action of stands of acacia trees. But demands for more intensive production of ground nuts soon led to mechanization and the removal of tree cover so that tractors and animal-drawn equipment could work more easily.”

With the trees gone, soil fertility fell. Artificial fertilizers took up the slack--for a time. But when fallowing was discontinued as well, “soil fertility dropped so much that the amount of artificial fertilizer that had to be applied began to make the crop uneconomic.” The upshot was many treeless, cropped-out farms left open to the desert winds and sands.

Mechanization’s Mixed Effects

Modern agriculture has had mixed effects elsewhere. In the United States, switching from horse-drawn to petroleum-powered farm machinery has permitted many fields formerly needed to feed the horses to revert to forest. Greater crop yields per acre have rendered other fields superfluous.

On the other hand, petroleum-powered machinery has facilitated the dredging and clearing of seasonally flooded forests, most notably in the South. It has enabled strip miners to peel away forest floors to get at coal and other minerals. And it has opened up formerly inaccessible forests to loggers.

“A petrochemically intensive economy, great transportation network, and the Caterpillar tractor have enabled us to deforest America so fast,” says Tim McKay of the North Coast Environmental Center in Arcata, Calif.

Worse may be in store. Devastating as deliberate deforestation has been in this and other countries, the inadvertent poisoning of forests throughout the industrialized world by airborne pollutants is potentially even more destructive.

One pollutant is ozone, created when ultraviolet rays in sunlight react with hydrocarbons and nitrogen oxide exhausted from autos, power plants and factories. Another is acid rain, created when the oxides of sulfur and nitrogen from smokestacks and motor vehicles react with atmospheric moisture and fall to earth as acidic rain, snow, fog or dust.

Losses in California

Ozone has damaged trees in national forests and parks in Southern and Central California, including 58% of the pine and oak trees in Yosemite National Park and 87% of the pines in Sequoia and Kings Canyon national parks. It has reduced tree growth. It has weakened trees so that they are more susceptible to damage from root rot, bark beetles, drought, windstorms, fire, frost and other stresses. And it has killed trees indirectly, including 57% of all trees in the most affected areas of the San Bernardino Mountains downwind from Los Angeles.

In the East, acid rain is causing die-back in spruce and fir forests in the Appalachian Mountains from Maine to North Carolina. It is suspected of contributing to a 20% to 30% decline over the last decade in the growth of pine trees in the foothills and mountains of Southern Appalachia.

But the worst hit is heavily industrialized Central Europe. Signs of damage there have emerged rapidly, with little warning. Five years ago, 8% of West Germany’s forests showed signs of damage. The figure had jumped to an alarming 52% by 1985. The situation in heavily polluted Czechoslovakia and Poland is reportedly even worse. And in Switzerland, where 50% of forests are afflicted, fears have been raised that a continuation of the present trend will destroy tree cover that for centuries has provided natural barricades to mountain avalanches.

And now comes an even greater peril--radiation. Last year’s nuclear power plant disaster at Chernobyl in the Soviet Ukraine irradiated extensive pine forests in the area, prompting Soviet officials to conclude that the most heavily contaminated sections would have to be leveled and their trees buried.

This signals an all-time low in the fortune of forests. Long destroyed to provide lumber, farmland and other benefits, forests now stand in danger of being deliberately destroyed without yielding any benefits at all.