President Carter, predicting major increases in lumber demand, yesterday proposed to Congress that less of it be cut from federal lands and far more taken from state and private forests.

In what is seen as a significant policy shift, Carter's five-year recommended program for the U.S. Forest Service would reduce timber cutting in the 187 million acres of national forest despite a projected one-third to one-half increase in timber demand by the turn of the century.

Instead, Carter proposed a major increase in forest wilderness areas and called for a program of beefed-up incentives and aid for state and private forest growth.

However, Carter avoided mentioning that the timber cutting will be reduced to the point where levels authorized in the 1975 plan will not be reached again until the year 2000. Instead, he said, increased productivity is needed in private and public forests.

"National forests will continue to be managed under multiple-use, sustained-yield principles to assure a continuous flow of all goods and services," Carter said. "In the long run, private forest lands are expected to become a chief source of increased timber supply, but during this decade, careful consideration must be given to increased supplies from federally owned lands, particularly the national forest system."

The president said he had asked that timber goals of between 11 billion and 12.5 billion board feet by 1985 be reached by departing from the Forest Service's longstanding policy of cutting only as much as grows to replace it.

That, said Merle Conkin, planning manager of the National Forest Products Association, was "the only good thing in the program," even though it wouldn't be needed. The projected harvest for 1980, he said, is already 12.2 billion board feet without any incursion into the stock.

"He's talking one way and doing the other," Conkin complained. "Here you have an assessment document reconizing that the 1980s will bring a very strong demand for wood products, but the program goes in the wrong direction by recommending falling wood cuts."

Environmentalists, on the other hand, were predictably pleased by the policy statement. "We think this represents a realistic program, much more realistic than the 1975 version," said Peter Kirby of the Wilderness Society.

In a 630-page assessment of the future of the nation's forest and range lands, the Forest Service predicted a 60 percent increase in lumber consumption by the year 2030: from 42.7 billion board feet in 1976 to 67.3 billion.

At the same time, demand for outdoor recreation facilities will more than double while grazing land demand will rise 40 percent by 2030. Noting that 53 percent of the country's 832 million acres of forest and range land is in private hands, Forest Service chief R. Max Peterson told a news conference that reforestation aid to state and private foresters will boost replanting by at least 100 percent by 1985.

Forest service funding for research and technology transfer will be increased under the five alternative approaches that the president outlined, stressing efficient timber harvesting and wood use practices, better residue harvest and delivery systems and use of wood and its wastes for energy purposes.

Mineral and energy resources under the national forests will be developed "within appropriate environmental constraints," Carter said.

The net effect of the growth in timber demand for housing will, of course, be higher prices. "The sharpest increases [will be] in the 1980s when housing starts are expected to be at peak levels," the report said.

"Thereafter, prices will continue to increase but at a slower rate . . . prices for minerals, especially energy resources, will increase at rates close to wood prices."

Concentration on improved management techniques is crucial because of increased competition among recreation, wilderness and wildlife demands and foresting, the report said. Such competition, it said, "may lead to more restricted and less satisfying opportunities and a gradual deterioration in the quality of life that the nation has come to appreciate and expect."