Under a program of "vegetation manipulation" designed in part to provide more water for the West's growing human population, the Interior Department is proposing to cut down hundreds of acres of aspen trees in scenic areas around this famous resort.

The clear-cutting plan, based on experiments suggesting that cutting mountain trees will increase water runoff into rivers during the spring thaw each year, will be used only on aspen because Interior Department officials believe that the aspen consumes more water than other high-country species.

Officials of the Bureau of Land Management said they will issue a final environmental impact statement this month on the plan to clear-cut aspen in the Glenwood Springs Resource Area, a half-million-acre region just west of the Continental Divide.

Al Wright, manager of the bureau's Glenwood Springs area office, said the plan involves cutting "patches" out of aspen groves on about 300 acres of public land each year for the next 70 years.

The aspen, a straight, slender tree with silvery bark and delicate fan-shaped leaves that in the fall turn a brilliant gold known around here as "aspenglow," is widely recognized in this region as a symbol of the natural beauty of the western mountains.

"It's an emotional tree," said Hans Hess, a BLM biologist. "For many people, it represents the esthetic values that made them want to live in the West in the first place . . . , but as more people come here, they need more water."

The relationship between cutting aspen and increasing water supplies is explained by Grant Loomis, the government hydrologist who wrote the original proposal:

"The melting snow and rain runs off the mountains into the Colorado River, or else it percolates down into the soil profile. But the aspen roots soak up water and send it up to the leaves; then it transpires, or evaporates, and that water never gets to the river.

"So if you cut patches of aspen, you eliminate some of the evapo-transpiration loss and more water goes into the river."

The supply of fresh water is one of the crucial limits to further growth in the Southwest, the fastest growing section of the country in the late 1970s. The Colorado River, a major source of water for Colorado, Utah, Arizona, Nevada and southern California, already is overallocated. That is, if each of those states took out of the river its full legal share of water, the Colorado, which cuts the Grand Canyon and fills lakes Mead and Powell, would run dry.

When the BLM set out to prepare a long-range plan for management of the Glenwood Springs Resource Area, an important watershed for the Colorado, it formed an advisory group of local citizens and governments and asked what the federal government should try to do with its land. Wright said the group's first recommendation was "increase water yield."

The Forest Service has been experimenting for decades with tree cutting to increase water runoff. Those studies suggest that of all trees in the high Rockies--chiefly scrub oak, aspen, spruce and fir--the aspen draws the most water from the ground.

This winter, therefore, when the bureau issued a draft management plan for the area, the paper included a program of "vegetation manipulation to increase water yield." The vegetation most suited for manipulating, the report said, was aspen trees.

When Carolyn Johnson, director of the Public Lands Institute, a Denver-based environmental outfit, determined what that meant, she warned local newspapers that the government was going to cut down "the crowning glory of the Colorado mountains."

The result was an outpouring of letters and editorials denouncing the bureau and its aspen-cutting idea.

Johnson charged that the clear-cutting was designed to provide more water for the Union Oil Co.'s shale oil facility in the resource area. Government and Union Oil officials denied this.

The bureau responded to the furor by promising to reconsider the "manipulations" before producing a final management plan, to be issued later this month as a final environmental impact statement.

In recent interviews, however, BLM officials have confirmed that the final plan will include clear-cutting of aspen trees. The difference will be that, in the final statement, water yield will not be listed as the primary rationale.

"As a matter of fact, there are several valid forest management purposes in managing the aspen," said Wright, who used the term "managing" to mean "cutting." "Frankly, our big mistake in the draft statement was saying we were managing the trees just for water yield."

Historically, aspen have been destroyed periodically by natural fires. But modern methods of fighting forest fires have stopped this process in many places.

Wright said cutting bare patches out of large stands of aspen will provide a more diverse habitat for wildlife and plant growth.

Further, he said, young aspen trees that cannot grow in the shade of older ones can grow in the cleared areas. This is essential to the future of the species because mature aspen stands eventually give way to spruce and fir. "Basically, if you don't manage the aspen, you're going to lose it," Wright said.

In the final plan, the bureau will set forth terms of a long-range study to measure how much increase in water yield will result from the clear-cutting.

The management plan for the Glenwood Springs Resource Area was designed as a model for forthcoming plans in dozens of other BLM regions throughout the West.

Officials of the Gunnison Basin Resource Area, south and west of this resort, recently announced a separate aspen cutting plan there. The news release carrying this information carried the headline, "BLM To Improve Big Game Habitat."