Its mountains, lakes, and woods have made Switzerland a tourist mecca for centuries. But now, the country's woods are dying. The recent news came as a terrible shock to this nation of nature-loving hikers. The Swiss had thought their green belt largely spared from the dying-woods phenomenon that has struck large tracts of trees in West and East Germany, Czechoslovakia, Poland, and Austria.
''We believe that the damage could be, or will soon be, in West Germany's range, where an estimated 35 percent of woods are affected,'' said Werner Spillman, central secretary of the Swiss Society for Environmental Protection.
Figures are available on very few regions, but they are alarming. In the flatland cantons of Aargau, Solothurn, and Thurgau, 25 percent of silver firs and 10 percent of spruce firs have died in the last year, and many more trees are affected. Even the mountain canton of Graubunden is reporting unusually high damage to trees in some of its Alpine valleys.
The culprit most often blamed for killing the trees is air pollution through automobile and heating emissions and acid rain. It is recognized that acid rain and the process of destruction require much research, as little is known.
But Swiss Minister for the Interior Alphons Egli says the situation is so ''grave'' that Switzerland cannot afford to wait. Those factors already known to be contributing to the problem must be fought now.
This opinion is shared across party lines. So this month the federal parliament passed a stricter environmental protection law than had been thought possible. With a federal election on Oct. 23, politicians who had fought for a weaker bill voted docilely for a tougher version. The public outcry to ''save our woods'' is such that being a softy on environmental protection is a heavy load to carry.
About 75 percent of acid rain drifts into Switzerland from the heavily industrialized regions of West Germany, France, Italy, and Eastern Europe. International cooperation will be far from easy, with both Western and Eastern blocs out to protect their industrial position. Interior Minister Egli has set up talks on acid rain with the West Germans and Austrians.
More than 90 percent of pollution from automobile and heating emissions is caused domestically. Reducing these emissions means slowing the country's motorists and wearing a thicker pullover around the house at night.
A compulsory maximum for room temperatures in winter of 20 degrees C. (68 degrees F.) is under discussion. But the top priority on Switzerland's list of solutions is putting a maximum speed limit on autobahns of 100 kilometers (62 miles) per hour.
As Gerhard Leutert of the federal environmental protection office says: ''A car driven at 100 kilometers an hour instead of 130 releases 25 percent less nitric oxide.''
Switzerland and Sweden already have the strictest automobile emission regulations in Europe. But they are still far behind the United States. There is pressure to reach US levels.
Many people like the idea of observing one car-free Sunday a month. Those who do not need to be on the roads would be banned from driving.