Environment : In the Amazon, Forest and Farmers Have to Get Along : To save Brazil’s tropical wilderness, experts say, alternatives are needed to destructive farming methods. They believe the region can be profitable and preserved.

The sprawling, air-conditioned hotel at the edge of the Amazon forest teemed with ideas for saving the world’s biggest tropical wilderness. It was a flourishing ecosystem of ideas, with the exuberance of a triple-canopy jungle, some ideas like towering trees, others like dense undergrowth and entwining vines.

They sprouted from the mouths of conservationists, researchers, government technicians and officials; they blossomed from photocopied treatises, slide projectors and posters; they germinated on note pads and paper napkins. The lush proliferation of ideas left no doubt that an international conference called “Forest 90” was a fertile theoretical environment.

A sampling:

Dirigibles will float over the wilderness, lowering in loggers to cut mature hardwood trees with as little damage to the forest as possible. New trees will be planted to replace the harvested ones, which will be hoisted into the sky and carried to nearby rivers, then floated to distant sawmills. No more logging roads slicing destructively through the fragile flora and fauna.

Forest dwellers will not only tap rubber and gather Brazil nuts, as they do today, but also will collect foods, medicinal plants, gums, fibers, dyes, oils and other products for marketing in Brazil and abroad. Useful species will be reseeded. In riverside settlements, processing plants and cottage industries will turn forest products into finished goods, providing needed jobs.

Agricultural extension workers will help farmers cultivate combinations of trees that yield profitable crops on small plots, protecting the land from the erosion and hardening that can occur when the forest is removed. This sustained “agroforestry” will render unnecessary the slash-and-burn farming methods that have already destroyed so much native forest.

Landowners will raise big, fast-growing Amazon fish in ponds covering a few acres, earning much more than they could by raising cattle on large tracts of cleared land. Waste from chicken coops at the edge of the water will feed the fish.

Two million Amazon colonos, pioneer farmers from other parts of Brazil, have shown how the imperative of economic survival can devour virgin forest. Most colonos begin by planting traditional subsistence crops such as beans, corn and an abundant root crop called manioc on cleared forest land. When the soil wears out in two or three years, they clear more land. More rain forest disappears.

Saving the forest, it was clear here, is not only a matter of curbing rapacious ranchers, but also of offering small farmers economic alternatives to destructive methods.

Like the vast rain forest itself, the ideas for weaning farmers from the slash-and-burn cycle seemed to have no end.

Plant manioc in combination with nitrogen-fixing legumes that will replenish and protect weak soils. Exploit unwooded river flood plains with intensive cultivation of rice or super-grasses to feed livestock. Grow shade-seeking perennial crops, such as pepper and cacao, under otherwise useless secondary forest growth, capoeira, on the deforested land. Develop more productive agroforestry “consortiums” of different crop trees that thrive together.

The goal is to “fix the man on the land” with a sustainable system of production. “For every year this person doesn’t have to move, it means ‘X’ number of acres that aren’t cleared,” said John Butler, a consultant with the World Wildlife Fund.

But Forest 90’s 1,200 participants--environmentalists and government officials--well knew that as deforestation chews away at Brazil’s Amazon region, ideas alone will not save the unmatched diversity of its myriad plants and animals.

While the impressive flood of ideas offered hope for the Amazon, it also underlined a difficult challenge: A monumental effort is needed to sort out the various forest-saving possibilities and to put them into widespread practice.

To accomplish the goal, new techniques must be taught, and other assistance delivered, to a rural population of 5 million in an area nearly three times as large as Alaska. That could require an army of agricultural extension agents. Currently, few results of Amazon agricultural research reach farmers in the field.

Luiz Carlos Molion, a Brazilian climatologist and forest hydrologist, served himself a few chunks of river fish from the hotel’s luncheon buffet.

“This is tambaqui, but it’s undersized,” said Molion, 43, a stout man with a ruddy face and scraggly russet beard. “They’re taking small fish from the rivers because the big ones are being fished out.”

Demand for tambaqui and other Amazon fish is high: A kilogram of tambaqui costs more than a kilogram of beef in Manaus, a city of more than a million people. Molion and others who know the Amazon say fish-raising in ponds could become a major source of food and income for the region’s people, with a low ecological cost. But so far, little has been done to implement the idea.

Leonir Naumann is an exception rather than the rule. He operates a farm near the village of Bela Vista, 40 miles west of Manaus on the Upper Amazon River. And on his farm he has a fishpond, full of maturing tambaqui, tucunare and pirarucu.

Naumann, 33, walked along the shore and pointed to fish breaking the pond’s surface. He said he soon will take his first catch to market and his farm will begin to turn a profit for the first time in the 10 years he has owned it. He also has 135 head of dairy cattle, but he said poor Amazon soil makes pasture maintenance too expensive to be profitable.

He wore sandals and blue shorts, and his tanned shoulders shone like copper under the midday sun as he stopped to make a simple calculation: Each cow requires 2.5 acres of grazing land, but 2.5 acres of fishpond will produce more than 150,000 pounds of tambaqui in three years. He feeds the fish dried cow manure and manioc--a crop he also fertilizes with manure.

About 740 acres of forest has been cleared from Naumann’s 4,300 acres of land, and he said he will cut no more. “I am against deforestation,” he said. “There is a lot of deforested land and it isn’t being used.”

More than 100,000 square miles of Brazil’s Amazon forest has been razed for pasture, an area larger than Oregon. An estimated two-thirds of that has degenerated into brush and the secondary forest growth, capoeira.

Agroforestry has proved to be one of the most productive uses of cleared Amazon land. Over the years, Sebastiao Silva Martins, 65, has planted a small jungle on his plot outside Bela Vista. His trees produce rubber, cacao, oranges, passion fruit, mangoes, palm peaches and cupuacu. Some thrive in the shade; others grow high, seeking sunshine.

The trees protect the fragile soil from hardening and erosion. They produce year after year. The tree farm doesn’t require much work, and Martins doesn’t have to spend money on such things as fertilizer.

“The fertilizer is just the leaves,” he said.

Like Naumann, Martins gets no help from agricultural extension workers or ecologists. He has learned which combinations of trees work best from talking with his neighbors and experimenting. In his small way, he has demonstrated that farming in the Amazon need not destroy the forest.

The biggest controversy at the conference was about “extractive reserves”--forest areas set aside for residents to exploit without destroying them. The government has created four extractive reserves with a total of 5.4 million acres and others are being planned. But debate goes on over whether they will be economically sustainable in the long run.

Critics said prices for forest products such as natural latex, nuts and herbs cannot adequately compensate for the time it takes to gather them. They contended that when demand increases for a forest product, it will be depleted--or domesticated for more economical production on farms.

Defenders of the concept argued that markets for new products must be developed. They predicted that the forest’s hundreds of thousands of plant species, many of them yet to be studied, will be a cornucopia of marketable new material. And they said forest areas can be “enriched” by planting.

Americans interested in rain-forest conservation already have begun buying ice cream and other products made with Amazon ingredients. Some conference participants envisioned a boom in demand for “rain-forest chic” products.

“Either we find ways to preserve the forest and improve the lives of the people there, or 20 or 30 years from now there won’t be any more researchers researching the forest, because there won’t be any forest,” said Julio Barbosa, a rubber-tappers union leader.

Environmentalists and government officials at Forest 90 agreed that the Amazon should be zoned for forest preservation and controlled development. Jose Goldemberg, the national secretary of science and technology, said a regional zoning plan is being prepared and will be finished by 1992.

Alcir Meira, superintendent of the official Amazon development agency, said the agency is drafting its sixth plan for the region. The agency, known by the acronym SUDAM, dedicated much of its efforts in the past to fostering big cattle ranching projects in the Amazon, granting tax concessions and other incentives. But Meira said the new plan will emphasize ecological balance.

“What it will not permit anymore is to give incentives for cutting down forest for ranching,” he said in an interview.

Molion, the forest hydrologist, is creating a new Amazon agency called Unitrop that will distribute donated funds for research on ecologically compatible development and for extension work. He said one of the first projects to be sponsored by Unitrop will distribute minnows and teach farmers to operate commercial fishponds.

“You don’t need to cut the forest to plant and harvest it,” he said.

That, in essence, is the gospel according to Forest 90. The future of the Amazon may rest largely on whether its message is heard.