WHEN YOU OWN the crown jewels, what do you do with them?Lock them up or use them-or sell them?

We do not ask the question aimlessly. The House of Representatives begins debate today on what should be done with the natural crown jewels of America: the mountains, rivers, forests and wildlife of Alaska. While that debate is likely to be argued in terms of whether these treasures should be locked away or exploited, the real issue is better described as which of them should be brought out of safekeeping at one time.

The answer, if anything has been learned from the history of other, once-unspoiled areas of the nation, is that only as much of Alaska's resources as are now needed should be opened up for development. The rest should be left for future generations to do with as they will. If Congress will keep that lesson in mind as it wades into the great Alaskan debate, its members may be better able to sort out the conflicting facts and rhetoric that are raining down on them in torrent force.

The three versions of an Alaskan land bill now pending before the House set out the alternatives clearly. All of them are "conservationist" bills in the old-fashioned sense of the word. All of them set aside under federal protection stretches of Alaska so vast that the mind boggles at their size. But only one, the bill sponsored by Reps. Morris Udall (D-Ariz.) and John Anderson (R-Ill.) and vigorously supported by President Carter, gives those vast areas the protection from human encroachment they deserve.

The arguments in the House today and next week will focus on oil, gas, minerals, hunting and transportation. Many truths will be spoken on both sides. The nation could use more of Alaska's oil and gas and minerals and timber now; Alaskans could use better access now to many parts of their state; hunters, sport as well as commercial, could use more wilderness areas now.

But the test throughout this debate should not be whether these things can be used now. It should be whether they are needed now or whether they should be preserved untouched for the future when they may be even more useful. If that test is applied, the House will adopt the approach of the Udall-Anderson bill on matters as diverse as the oil and gas under the Arctic National Wildlife Range to the timber of Admiralty Island. The treasure it will vote to dole out-and there is much of it in this bill-will be that which is now needed and which can be wisely used. The rest should be held in safekeeping for another generation.