Despite last summer's devastating fires in Yellowstone National Park, it would be a mistake to completely scrap the government's let-it-burn policy as some critics are demanding.

Even so, there is still considerable room for improving how the policy is administered and determining when it is no longer appropriate.That much should be clear from the joint hearings being held this week in Washington, D.C. by the national parks subcommittee of the House Interior Committee and the forest subcommittee of the House Agriculture Committee.

Though the hearings focus on the 1988 conflagration in Yellowstone, the proceedings have broad implications since the let-it-burn policy applies to all states with extensive federal park or wilderness lands.

The hearings have provided some comfort for the many Americans concerned about the future of Yellowstone. Although last summer's fires were initially seen as devastating most of the park, it is now believed that less than one-third of Yellowstone actually lost trees and most of what burned is expected to recover in a few years.

While that's certainly good news, the fires still inflicted major damage on the reputations of the National Park Service and the U.S. Forest Service.

An internal memo provided during this week's hearings noted that National Park Service staffers in Yellowstone fought last summer's forest fires so unenthusiastically that critics might well charge them with illegal use of funds. The memo is especially stinging because it was written not by an outside critic but by a Park Service insider, Sequoia National Park fire specialist Howard Nichols. He paid a one-week visit to Yellowstone starting last July 28 to help project the course of the fires.

The situation in Yellowstone became so bad last summer that on July 21 Interior Secretary Donald P. Hodel finally ordered the Park Service to drop the let-it-burn policy and fight all fires.

This week, even as they reaffirmed their commitment to the let-it-burn policy, the Park and Forest services hurt themselves at the Washington hearings by admitting they don't have enough money to implement the policy effectively. Yet this funding situation never seems to have entered into the services' calculations in dealing with last summer's fires at Yellowstone.

Neither does the government seem to have taken into account the special conditions at Yellowstone that aggravated the fires there - the drought, high winds, and an insect infestation that had killed but left standing thousands of acres of lodgepole pine.

Before 1972, government policy called for suppressing all fires in parks and wilderness areas. The policy was changed after it was discovered that decades of accumulated ground debris and deadwood were preventing new trees from growing.

The policy in effect last summer was to let natural fires burn without getting out of control and to suppress all man-made fires except "proscribed fires" set by forest managers in an effort to clear out undergrowth. The Park Service, however, had not set any proscribed fires in Yellowstone for years, believing that the park's high-altitude lodgepole pines were too difficult to burn in controlled fashion. As a result, experts believe that decades of accumulated debris may have helped set the stage for last summer's conflagration.

Though the Yellowstone fires do not justify scrapping the let-it-burn policy, some fine-tuning of the policy and the procedures for administering it are clearly in order.