THE U.S. FOREST SERVICE is taking an inventory - and inviting suggestions - of woodland to be permanently protected as wilderness. There is no designated wilderness in George Washington Forest, but the service has identified eight areas that deserve consideration. For people in the Washington area who enjoy getting out of doors, it's a reminder of the wealth of public land, some of it of great ecoligical interest, that lies only a few hours' drive west of here.

George Washington Forest covers a gigantic stretch of land in the mountains just beyond Shenandoah National Park. The forest runs almost 150 miles along the border between Virginia and West Virginia. Other national forests lie along its borders: Jerrerson to the South and Monongahela to the west. The forests are far less well-known that Shenandoah Park, which is becoming so crowded and overused that parts of it sometimes look like the city. Last month the park recorded nearly half a million visits, a staggering 35 per cent increase over the same month last year. Many of those people simply wanted to ride along the Skyline Drive. But for people who prefer to fish or camp or simply walk for an afternoon at a distance from the rest of the human race, there are greater possibilities in the national forests.

In time, no doubt, some of the deluge of visitors to Shenandoah will begin to pursue those further possibilities, increasing the pressure for recreational development there. The forest service has already built roads and some campgrounds. There is room for more. But there are also parts of those mountains that ought to be left precisely as they are right now. A valley west of Staunton, for example, contains one of the very few stretches of woodland in the Eastern United States that has never been cut, and there are magnificent stands of giant hemlock along the stream bottoms.

The wilderness designation legally bars the construction of any roads, power lines or buildings. It prohibits off-road vehicles, and the woods will never be timbered. Only Congress can grant that designation. It's a slow process, and the forest service's inventory is an early stage of it. But it's and enlightened effort to indentify some of the Appalachians' most interesting and, in the scientist's sense of the word, valuable woods. That legislation is going to be needed to protect them for - and, you would have to add, from - the growing populations of the big cities to the east.

People who want to nominate sites in the George Washington Forest, or comment on the forest service's criteria, have until Sept. 15 to write to the Forest Supervisor, Federal Building, Harrisonburg, Va. 22801. If you want to write about sites in other national forests, send the letter to the U.S. Forest Service, Post Office Box 2417, Washington, D.C. 20013.