THE national parks system in the United States faces major fiscal difficulties, as the Monitor series by Robert Cahn this week has pointed out. The parks enjoy a steady increase in the numbers of Americans who seek out their nation's natural wonders and historical sites each summer - and increasingly in other seasons as well. But the resources needed to maintain the parks are stretched thin in these days of budgetary pressures. Under current budget practices in Washington, getting more money for one federal program requires slicing it from another. How will the parks fare in this fiscal environment?
At the least, the present level of spending should be sustained, with resources shifting to such crucial areas as ranger salaries. And extra vigilance is demanded to assure that the Park Service not be loaded down with added responsibilities for new park areas pushed through Congress as pet projects of particular legislators.
The critical need is protection, and optimum utilization, of the areas already under Park Service care. The park-visiting public benefits, of course, from well-maintained, adequately staffed parks. But the public benefit could be enhanced if the parks' potential for scientific research, as well as recreation, were more fully exploited.
The vast natural areas of the parks could be superb laboratories for studying the interdependence of species within ecosystems and the impact of man-made environmental phenomena such as global warming and acid rain. Some of this activity is already under way at national parks, but it's the barest of beginnings.
With relatively small investments, like the $1.9 million currently being spent for global climate-change research in a few of the 357 park units, programs with potentially big payoffs to the public could be nurtured.
Mr. Cahn's writings over the past 23 years - beginning with his original Pulitzer Prize winning series in the Monitor, ``Will Success Spoil the National Parks?'' - have underscored both the inherent value and fragility of America's parklands. Perhaps the question for the 1990s is, ``Will the National Parks Go Begging?''