In 1995, a Rwandan named Gad Tegeri cut down a tree in the Gishwati Forest Reserve, 30 square miles of soaring hardwoods in the hills east of Rwanda's largest lake.
He and his family, returning to Rwanda from exile in Congo, needed land to grow food. The Gishwati forest seemed more fertile ground for restarting life than United Nations refugee camps outside the city of Gisenyi
So, with his wife, baby daughter and his machete, Tegeri climbed the slopes into the forest and started chopping. Other refugees followed and cleared more land for themselves.
Over the next five years, tree by tree, they cleared all but a few acres of what had been a protected forest. They replaced the African mahoganies and kosso trees with a patchwork of corn and potato fields that helped free them from U.N. handouts of food.
And now, in part because of Tegeri and other former refugees like him, Rwanda is almost devoid of trees.
It is another misfortune for Rwanda, a debilitating side effect of the violence in 1994 when gangs of Hutus, the majority ethnic group, killed an estimated 800,000 people, most of them Tutsis. Although the destruction of forests was largely ignored at the time, that loss of forestland is bringing ruin to the country's farmers and to Rwanda's economy.
Rwanda is Africa's most densely populated country and one of the most intensively farmed. Almost every hill is terraced and farmed, the mountainsides stepped in lush green strips. Bean and sorghum fields press against red-tiled houses; banana trees are cultivated right up to the edge of paved roads.
Until the mid-1990s, the government managed to protect the country's forest reserves from the population pressures. But by the time refugees such as Tegeri were on the move, environmental concerns were no longer anyone's priority.
Rwanda, because of the killings, experienced one of the largest, fastest population shifts in the 20th century. When Tutsis gained control of the government, millions of Hutus fled into neighboring Congo (then known as Zaire), and close to a million Tutsis who had fled to escape the slaughter returned. Tens of thousands of other Tutsis who had left Rwanda years before now seized the chance to return home.
"After the war, we thought it would be better here," says Tegeri, who returned after decades in Congo. "We thought we would find good farmland."
He and other refugees first crowded into Gisenyi, on the border with Congo. Members of the Interahamwe - the militant Hutus largely responsible for the genocide - sometimes slipped over the border and attacked them.
"We were very scared," says Mwiza Vareriya, 20, who lost five relatives to the Interahamwe. "But then we got to the forest, and we felt safer."
The U.N. and Rwanda's new government encouraged their move. The government declared a small section of Gishwati Forest open for settlement, and U.N. workers built long lines of aluminum-roofed houses.
"There was no focus on conservation or environmental protection," says Teddy Musabe, a lecturer on environmental management at the National University of Rwanda. "It was just an emergency. There was no long-term planning."
Vareriya, her parents and her seven brothers and sisters cleared 2 1/2 acres to plant corn, peas and potatoes. Tegeri helped settle 1,350 other families he had lived with in Congo, and was elected a leader of their new village. Other refugees, as well as Rwandans in search of land, arrived to claim patches of hillside. People moved farther south into the forest, closer to the sources of the Sebeya River. And one by one, the trees came down.
Tegeri lives in a village called Arusha along the switchbacks of a steep, rocky dirt road. This was once the northern edge of the Gishwati Forest, a tropical jungle of thick trees, vines and wild bush. Today it is farmland. There are no indigenous trees left - they all fell to machetes in the mid-1990s.
At first, Tegeri says, he and other residents cleared most of the trees and bush so they could plant crops. When the Interahamwe began hiding in the forest in 1997, the villagers cut whatever remained, for safety.
Now the hillsides lack the root systems that once stabilized the soil. And they lack the thick leaf canopies of the trees that once softened the rains.
Autumn and spring are Rwanda's rainy seasons. Given the lack of trees, those rains can be counted on to wash away the road, Tegeri said. And without a passable road, villagers have all but given up trying to sell their corn and sorghum at the market below the hills on the tar road that leads to Gisenyi. They farm for only subsistence now.
But even subsistence farming is becoming more difficult, in a country where farming is the livelihood of 90 percent of the population and accounts for about half of the country's economy.
"The soil, it's not like it was," Tegeri says. "People here are so many, so they farm in the same place every season, every season, every season.
"Since we arrived here, the amount we are harvesting is down. It's reduced, I'd say, by 40 percent."
Many of the fields around Arusha glimmer an improbably bright green, but most also have long scars of bare earth, the signature of erosion, or have the large brown handprint of mudslides. Landslides from the denuded mountains have killed dozens of people in the villages below.
As early as 1999, the government recognized the entry of refugees into the Gishwati Forest as an ecological disaster. It ordered thousands of families to leave the reserve and announced that felling trees there remained illegal. But few people complied.
Officials at the Ministry of Lands, Environment, Forestry, Water and Mines could not be reached for comment about their policies, and officials at the government's Information Office said they were not informed about events in the forest reserve.
Aid groups and the government are encouraging residents to plant trees to try to stabilize the remaining topsoil. Tegeri said his community received money for this reforestation but found it little help: Most of the saplings died. There was no money to buy more. "We need experts to help us," he says. "We don't know how to grow trees."
Deeper into Gishwati, beyond the neon green valleys of tea leaves and the ridges of terraced hills, people echo Tegeri's assessment of the land. A few years ago, they say, the soil was rich and food was plentiful. Now, they say, they are hungry.
"It's an environmental problem throughout Rwanda," says Glenn Bush, an environmental economist who studied the Gishwati region for the Rwanda chapter of the Wildlife Conservation Society. "The area of production has doubled, but the yields have declined by half."
The signs of attempts at reforestation include the skinny trunks of eucalyptus saplings teetering next to the stumps of hundred-year-old hardwoods. People plant shrubs known as imihengeli to border their fields, in an attempt to slow erosion.
Eucalyptus, a fast-growing but thirsty species, saps water from the damaged soil. The shrubs are said to attract rats, and the soil grows no richer, villagers say. They acknowledge that their problems are a product of deforestation, but even the small remaining stand of Gishwati Forest - about 2 1/2 acres, all that's left of nearly 20,000 acres - is under threat.
"I do this every day," says Nlanda Abanyanga Emmanuel, 35, walking from that patch of trees with a section of newly cut tree trunk on his head. "We need fuel."
There are only a few hardwoods left in the Kinihira village, which a year or two ago sat next to the forest. In the huge trunk of one remaining abyssinica, there is a hole big enough for a man to stand upright in. It is fresh, the result of hundreds of machete chops.
Last year, village elders told the several hundred people in Mwiza Vareriya's village that they had to leave the forest reserve.
Her family left their crops in the ground and carried their belongings down the mountains. Vareriya now lives in a small, mud brick house a quarter mile before the dirt road from Arusha meets the paved road to Gisenyi. A bean patch grows almost to her front door. Her neighbors tell her that even here, below the mountains, the soil is becoming poorer.
A mile from Vareriya's house, women collect water from a tributary of the Sebeya, the river that begins in the Gishwati mountains and travels through villages on its ways to Lake Kivu.
In recent years the river water has been the color of coffee: As rains strip topsoil from Gishwati's treeless hills, the soil is carried into the river, which people use for bathing and drinking. When the river water reaches the purification plant and hydroelectric station in Gisenyi, the nutrient-rich soil that would be so valuable in the fields ravages the machinery.
According to a study by Bush, the environmental economist, the Gisenyi drinking-water plant devotes 21 hours a week to maintenance, compared with nine hours a week before 1994. That is a productivity loss of more than 264 million gallons of water a year - in a region experiencing an acute shortage of drinking water.
"There are all sorts of downstream effects," Bush says. "But the economic consequences of the environmental degradation of that forest really weren't on people's radar. There were more important needs: resettling refugees."
At the Electrogaz hydroelectric station, brown river water gushes into cobalt blue Lake Kivu like a muddy cloud. "There is much sand in the water," says Stany Nizeyimana, the plant manager. "This sand, it makes the machines old quickly."
During the dry season, his staff turns off the power station's machinery twice a week so they can clean the filtration tanks. In the rainy season they do so at least four times a week. More than a quarter of his budget goes to fighting sediment; some months, because of the sediment, the plant's output falls by as much as half, causing power shortages throughout the region.
"It is because in Gishwati the people came and cut trees, and now they are staying there," Nizeyimana says.
Once in Lake Kivu, nutrient-thick Sebeya water feeds algae that suffocates the plant life below - the breeding grounds for tilapia, the mainstay of Rwanda's fishing industry.
In Arusha, in the steep hills above the lake, Tegeri has other worries. The community includes nearly 150 families led by widows, women whose husbands were killed by the Interahamwe. There are dozens of orphans. Tegeri's worry, he says, is whether the next generation will have food.
"Environmental management is one of the last things to get any attention," Bush says. "Now, the government is looking to move people out [of Gishwati], looking to reforest. But the bottom line is, where do you put the people? There's just nowhere to go."