In the summer of 1998, the Yangtze River basin of China suffered some of the worst flooding in its history. An estimated 120 million people were driven from their homes by the floodwaters. A reported 3,656 people died. This near record flooding with damages totaling $30 billion--came in a year when rainfall, though well above average, was not close to being a record. What was different from earlier years of comparable rainfall was the loss of forests. By 1998, the Yangtze River basin had lost fully 85 percent of its original forest cover, leaving little to hold the above-normal monsoon rainfall.'

(Let us interject that we cannot smugly think, "Too bad for China" for an article in the Sonday, April 7, 2002 Atlanta Journal & Constitution by Joan Lowy, titled Dust Storms Bring Toxins to U.S., has the opening paragraph: "There is increasing evidence that the giant dust storms originating in China and Africa may be blowing a toxic soup of air pollution, pesticides, insects, bacteria and viruses thousands of miles across oceans to the United States."!)

Although it was too late to prevent massive deforestation, in August 1998 Chinese officials announced that they were imposing a total ban on tree cutting in the upper reaches of the Yangtze River basin. A senior official observed that trees standing were worth three times as much as trees cut. The state logging firms that had been cutting the trees were converted into tree planting organizations. As one employee noted, "It's now time to put down the ax and pick up the shovel."

Because deforestation increases flooding, accelerates soil erosion, inhibits aquifer recharge, and decimates plant and animal life, it directly affects several other trends that are shaping our future. Although we do not rely as universally on forests for fuel wood as we once did, forests still provide material for building our homes and for manufacturing the paper that remains the principal medium for communicating information. In addition, 2 billion people depend on forests for fuel. Since the beginning of agriculture, the world has lost nearly half of its forests. Much of the loss occurred during the last century. Although some individual countries have reversed the tide of forest loss, the world's forested area continues to shrink. As this area diminishes, so does the human prospect.

Impressive though the Costanza team's analysis is, it omits one of the most valuable services provided by forests - namely, their role in the recycling of rainfall inland that makes the interior of continents productive and habitable. If we continue to destroy coastal forests, the interior deserts of continents will continue expanding, squeezing humanity into an ever smaller area.

We often discover the services that forests provide when it is too late, after the trees have been cut. This is perhaps most true of flood control, as China, Thailand, and Mozambique have belatedly discovered.

Forests also store nutrients. This is particularly important in the tropics, where almost all nutrients in forest ecosystems are stored in the vegetation itself. Many tropical soils have little organic matter and almost no nutrient storage capacity. If a forest is burned off to plant grass for cattle ranching or crops, whatever is planted can do relatively well in the first few years because of the nutrients remaining in the ashes. But once the ash washes away, as it soon does, the nutrients are gone. This is why much of the land cleared in the tropics quickly becomes wasteland and is abandoned.

Tropical rainforests are highly productive ecosystems, efficiently converting sunlight into plant material. But they can do this only as long as they are intact. Once they are destroyed, they can take centuries to regenerate. And some may never recover-simply because the conditions that existed at the time of their original formation may no longer exist.

Forests help control soil erosion by adding organic matter to the soil and by slowing the flow of water runoff. Leaf litter on the floor protects the soil from being loosened by raindrops, creating a tight link between the vegetation and the soils. The forest vegetation permits soil to accumulate and keeps it from washing away. The accumulated soil in turn provides a healthy medium for the forest to develop. In this symbiotic relationship, losing the forests sometimes means losing the soil, which may in turn prevent the return of the forest.

The ability of forests to slow rainfall runoff and let it percolate downward also means forests play a central role in the hydrological cycle. They recharge aquifers, the underground rivers that sup -ply water for the wells downstream. The more water that runs off when it is raining, the less there is to recharge aquifers. Thus the loss of forest cover leads to a double loss-more damage from flooding and a reduced recharge of aquifers.

Forests can purify drinking water as well. Wait Reid, who works with the Millennium Ecosystem Assessment, notes that "within the United States more than 60 million people in 3,400 communities rely on National Forest lands for their drinking water, a service estimated to be worth $3.7 billion per year." He then notes that this single service, one among many provided by national forests, is worth more than the annual value of timber harvested from these lands.

Another service provided by forests is protection of streams and rivers from silting. In the U.S. Northwest, for example, the clear cutting of forests has destroyed nearby salmon fisheries because of increased muddy runoff. Mismanagement of one natural asset is decimating another.

Reforestation is essential to restoring the earth's health, a cornerstone of the eco-economy. Reducing flooding and soil erosion, recharge aquifers, the nation rarely faces serious drought. Environmental degradation is contributing to chronic famine in one country while environmental restoration helped set the stage for economic success in an adjacent nation.

Shifting subsidies from building logging roads to tree planting would increase tree cover worldwide. The World Bank has the administrative capacity to lead an international program that would emulate South Korea's success in blanketing mountains and hills with trees.

In addition, FAO and the bilateral aid agencies can work with individual farmers in national agroforestry programs to integrate trees wherever possible into agricultural operations. Aptly chosen and well-placed trees provide shade, serve as windbreaks to check soil erosion, and fix nitrogen, which reduces the need for fertilizer. The only forest policy that is environmentally acceptable is one that expands the earth's tree cover.

A successful effort to reclaim the earth calls for a global reforestation effort, coordinated country by country, integrated with population planning and improved efficiency of fuel wood burning. Reducing wood use by developing alternative energy sources as well as systematically recycling paper and using fewer forest products are integral components of the campaign to lighten pressure on the land. With such an integrated plan, humanity can arrest the spread of deserts that threatens agriculture and human settlements in so many countries.

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