IN THE ARGUMENTS over the future of some 62 million acres of roadless national forest lands, two concepts of conservation are at odds. One views conservation primarily as the protection of valuable resources against exploitation and destructive use. The other views it as prudent resource management, and permits some timbering, grazing, energy exploration and other activities if conducted carefully, with exphasis on long-range public benefits instead of immediate or private gain.

The administration has emphasized the second view in its decisions about RARE II, the massive study of 2,919 untrammeled Forest Service areas in 35 states and Puerto Rico. In line with the Agriculaure Department's proposals in January, President Carter has decided to open about 36 million acres for multiple uses, including timbering, oil and gas exploration, mining, grazing and recreational development. He will ask Congress to set aside 15.4 million acres permanently as wilderness. Almost 10.6 million acres will be studied some more.

In short, Mr. Carter has concluded that almost three-fifths of this storehouse of untouched public resources should now be opened up, in response to energy pressures and other national needs such as the great and growing demand for wood. The decision is not as spendthrift assome preservationists maintain. This country has come a long way from the days when land, trees and fuels could be conserved only by locking them up. Timbering, in particular, can now be conducted in far less ugly and destructive ways. So can energy exploration. And lands that are no longer pristine can still provide valuable recreational space-and take some pressure off the wild back country, which is in danger of being trampled by its friends.

Congress may wish to overrule a few of the administration's decisions, especially in the Pacific Northwest, and set aside some larger tracts as wilderness. In general, though, the administration's program is reasonable. It does put a heavy burden on the Forest Service to manage the newly opened lands carefully and keep environmental damage to a minimum. That is crucial to the concept of conservation that the administration has endorsed, the one that relies on perennial watchfulness instead of perpetual no-trespassing signs.