Humans are wholly dependent on nature's cornucopia for food, clothing, shelter, many medicines, beer and wine -- to name just a few of life's essentials and pleasures.

We also appear hardwired to control, dominate and undermine the complex systems of nature that serve us.

From a biological perspective, the greater the diversity of life on our planet, the more likely we are to survive disasters and calamities of our own and nature's doing. Even as we have come to understand this scientifically, however, humans still seem compelled to impose order on the world, eager that nature might serve us more efficiently. Hence it is not surprising that we love the practical simplicity of monoculture, despite its high long-term costs.

For centuries, the wheat, cotton and wood of monoculture farming have fed, clothed and sheltered us. But our increasing dependence on fewer and fewer species has brought tragedy as well.

Wikipedia, an Internet encyclopedia, defines monoculture as "the planting and cultivation of a single species over a substantial area, or the practice of relying on a very small number of species for agricultural purposes."

Despite its drawbacks, monoculture remains enticing to large-scale farmers and the rapidly expanding agribusiness sector.

Even Patrick Moore, the now 58-year-old Canadian cofounder and former director of the environmental group Greenpeace (from its inception in 1971 until 1986), is known to enthusiastically support industrial forestry. "Grow more trees, use more wood," he is quoted as saying.

But like a parental admonition to "eat up, because children somewhere in the world are starving," most everyone has heard about the Irish potato famine, and its implicit warning to sow and reap with caution.

This catastrophe came about because, by the 1800s, the Irish had come to depend on one particular variety of potato known as the Lumper, which they found easy to propagate. Soon, nearly all the potatoes being sown across Ireland were genetically identical, and provided most of Ireland's 8 million folk with their staple fare. That was until a potato blight swept the nation in 1846, and wiped out the crop for three years running. In the end, more than 1 million people died of starvation and disease, and another 1 million emigrated, most to North America and Australia.

The potato famine taught farmers an important lesson about maintaining genetic diversity. But, with ever more mouths to feed worldwide, and ever more money to be made, ease and efficiency have increasingly tended to trump sustainable husbandry.

So losses continue. In the 1970s, American farmers lost over $1 billion-worth of corn to a fungus that wiped out genetically identical plants, and in the 1980s millions of hectares of grapevines in California succumbed to a single variety of insect.

"The drawbacks and risks of excessive use of a single species are acknowledged and well understood in agriculture and agricultural science. This has led to a realization of the benefits of polyculture," Wikipedia notes.

But there are admitted benefits as well. A Web site at the University of Reading, England, lists some of the advantages of monoculture, including: the ability to reduce plant competition for nutrients, space and sunlight; the ability to control undesirable (unprofitable) plants; cost reductions through limited use of specialized machinery; and, maximized profits from growing high gross-margin crops. "Monocultures can take many forms and are not necessarily environmentally 'unsound,' " the entry concludes.

Moore, formerly of Greenpeace and now principal spokesman for the Vancouver- and Chicago-based Wood Promotion Network, would agree. "I have never been opposed to forestry and have always believed that wood is our most abundant and sustainable renewable material resource," he explains in an August 2003 online article by Bernadette Freund. "I believe the correct environmental policy is 'grow more trees -- use more wood,' rather than the anti-environmental policy 'cut fewer trees -- use less wood.' "

Moore, who got his doctorate in ecology from the University of British Columbia back in 1972, continued: "Forestry is one of the most environmentally defensible activities of our entire civilization. My support for forestry is not based on its economic benefits, which are important in their own right, but on the environmental benefits."

Nevertheless, Moore admits that monoculture forestry can pose problems. "I think the tendency to go to single-species forests with insufficient consideration for biodiversity can be a problem. . . . There is nothing wrong with single-species forestry, any more than there is anything wrong with single-species farming. But, it is a fact that monoculture forests often have less biodiversity than multispecies forests," he explains.

And this biological diversity is vital to maintaining life on the planet. The myriad ecosystems, plant and animal species, and genetic variations that comprise the natural world are essential to the health and vitality of nature, whether wild or domesticated, on farms or in forests. It is critical for human communities as well, according to the UN Food and Agriculture Organization (FAO).

The biodiversity of forests is particularly important to humans. "Forest trees and shrubs play a vital role in the daily life of rural communities in many areas, as sources of timber, fuelwood, food, fodder, essential oils, gums, resins and latex, pharmaceuticals, shade, as contributors to soil and water conservation, and as repositories of aesthetic, ethical, cultural and religious values," it states on the FAO's Web site. "Forest animals are a vital source of nutrition and income to many people, are used for medicinal purposes, have important cultural roles, and have vital roles in forest ecology, such as pollination, seed predation and dispersal, seed germination, herbivory, and predation on potential pest species," it continues.

Increasingly, however, plantation forests made up of single species, such as pine and eucalyptus, are replacing natural forests. According to an FAO survey in 2000, plantation forests then covered 187 million hectares worldwide -- an area almost five times the size of Japan. Compare that with a similar survey done in 1995, which found 124 million hectares planted. In just five years, those two figures show, the global area of plantation forests increased by 50 percent.

Closer examination of that survey data shows that 62 percent of those plantations were in Asia (24 percent in China and 18 percent in India), with another 4.5 million hectares being planted annually across the globe, primarily in Asia and South America (91 percent). The most commonly planted tree was pine (20 percent), followed by eucalyptus (10 percent).

"Globally, 48 percent of the plantation forest estate was for industrial use, 26 percent was for non-industrial use [fuelwood, soil and water conservation, other] and 26 percent was not specified," the FAO's survey in 2000 reported.

The FAO assessment notes that although about 5 percent of forests worldwide are already plantations, "In the future, planted forests will have an increasing role in wood and non-wood forest products supply as natural forest areas available for this purpose decrease owing to deforestation or designation for conservation or other uses."

As these natural forests shrink, so does the biological diversity essential for the survival of all the plant and animal species that support the human race. "Genetic variation -- at the levels of species, populations, individuals and genes -- is an important part of biological diversity, since it is the basis of evolution and the adaptation of species to changes in the environment. Variation is also essential for selection and breeding to meet present and future human needs," states the FAO.

Since the vast majority of genetic resources worldwide are found in natural, unmanaged forests, from tropical rain forests to the boreal forests of the far north, there is an urgent need to protect and conserve our remaining forests and the wealth of biological diversity they shelter.

Unfortunately, too many politicians and policy-makers cannot see the forest for the trees, and seem to think that any forest is a good forest, even if all the trees are identical. After all, it's green, and green is also the color of money.

The World Rainforest Movement, a forest conservation organization, is particularly concerned that agribusiness plantations are rapidly fueling deforestation worldwide. "These plantations, promoted as 'planted forests,' are in reality crops -- and not forests -- and they are generally preceded by the clearcutting of the native forest ecosystem," the organization reports.

Farms, too, are being lost. In Uruguay, for example, 10 percent of the agricultural land has been planted with trees that will be chopped up, or chipped, for paper production. "Eucalyptus monoculture displaced the important cereal production [wheat, barley and sunflower) that had become one of the country's main export sectors," Raul Zibechi wrote in an article published last month titled "Two Sides of a Predatory Model."

And more expansion is expected. "The biggest foresters [in Uruguay] are the ones planning to install the large factories: the U.S.-based Weyerhaeuser owns 130,000 hectares of forest monoculture; Finland-based Botnia has 57,000 hectares; and Spain's Ence has another 50,000 hectares. . . . The American firm Weyerhauser intends to invest up to $1 billion in expanding its business in Uruguay," notes Zibechi, who is a teacher, writer and researcher in Montevideo.

Chile, too, is suffering predation. "With over 2 million forested hectares, [Chile] has been defined as the forestry model to follow," Zibechi observes. "However, municipalities where the increase in poverty has been highest are those in which, besides tree plantations, there are also cellulose and paper factories."

But monoculture forests that will be chipped for paper are not just being planted in the developing world. Corporations are now clearing natural forests worldwide for plantations, including in the southeastern United States.

"Many of the regional properties purchased by paper and pulp companies have been converted from their natural mix of hardwood and softwood species to a monoculture of pine plantation. After the cut, the land is replanted with pine seedlings and covered with fertilizers and herbicides to kill off competing growth," Brendan Jennings wrote in the fall 2000 issue of The Chattanooga CityScope.

These chemicals degrade soil and water quality, but so does planting only one species of tree.

Jennings' article contains this telling quote from Robert Gottfried, Professor of Economics at the University of the South in Sewanee, Tennessee: "There is faster [water] runoff and bigger peaks and valleys in the flow of streams in pine forests. This has economic implications. My concern is that we're rushing pell-mell to large scale changes in the landscape. We don't know what the long-range implications might be."

For others, the ramifications are already clear. "This is industry at its most efficient and most sophisticated, an industry that's going to squeeze the life out of diverse ecosystems," Cielo Sand, of the conservation group Forest Watch, told Jennings.

Comparatively speaking, perhaps, Japan is lucky. Yes, there are 10 million hectares of cedar plantations scattered across the nation -- and more than 20 percent of the population suffers from cedar-pollen allergies -- but change is rumored.

The New National Forest Plan approved by the Cabinet in autumn 2004 proposes that Japan's monoculture forests of cedar and cypress be partially cut and planted with broadleaf trees in order to increase forest biological diversity. Forty-four areas near major rivers have been chosen for diversification.

Sadly, even as Japan begins to diversify its own forests, its imports of paper and pulp continue to climb. In fact, worldwide paper consumption is rising steadily, fueling demand for pulp from both natural forests and plantations.

With the world's population growing steadily, the loss of natural forests may seem inevitable -- but is it necessary? We are now at a crossroads where we can decide what the word "forest" will mean to future generations.

Can we learn to manage our forests and our consumption of wood products so there will always be vast tracts of natural forest? Or are we consigning future generations to a planet of sterile plantation forests? Will trees someday be viewed in the same way we now see corn and soybeans -- just plants to be grown and harvested?

"There is increasing awareness of the folly of destroying wilderness areas, the wellspring of the earth's biodiversity. And it is clearly the case that reductions in the planet's gene pool -- well under way -- may eventually have catastrophic results in planetary pandemics among vulnerable plants, animals and humans," writes Helena Norberg-Hodge, in her essay, "Breaking Up the Monoculture." (www.isec.org.uk)

Of course, pandemics are a very real possibility. But perhaps more catastrophic for the human race would be if one day there is no true wilderness left; if our jungles and forests had all been cleared and planted to serve efficiency and profit, and if children come to see trees simply as crops.

If that day comes, we will have lost the magic and majesty, and the safety net, that has fed, clothed and sheltered us -- and has been one of the wellsprings of unique cultures worldwide.