In the Black Forest, the acid rain is said to attack all EXCEPT

Good morning, everyone. Today we’re going to talk about acid rain. You may wonder what is acid rain. Well, it is almost impossible to describe the mathematical relationship between what goes up as pollutant emissions and what comes down as acid rain. But we do know the primary source of acid rain is the power station smoke stack. The pollutants combine with moisture in the atmosphere and they fall as an acid mixture causing the rain. Do you know what the Germans call this acid rain? They call it royal water, because it can even break down gold.
    The royal water, I mean the acid rain, falls in rain or snow on the romantic Black Forest, and attacks the soil. Microorganisms within the soil collapse and metals harmful to trees like aluminum are leaked out. At the same time, the acid rain attacks the leaves and dissolves their waxy coating. The leaves then shrivel and die. About one in every ten trees in the Black Forest is a fir. 76% of all firs are dying. The first symptoms of death by pollution in a fir is the yellowing of the needles. At the back of the fir needle you can see the pores through which the plants breathe. The acid rain destroys those pores, and prevent them from closing. So on a warm day, the plant loses all of its moisture through all those open pores. The needles, as a result, turn yellow and die.
    The statistics that are available now are horrifying. Of these trees in the Black Forest, 41% of all spruce are diseased, 43% of all pine are diseased, 26% of beach trees, 76% of all fir trees and 16% of all others are dying. Environmental groups like Green Peace Campaign around Europe are trying to stop the acid rain.
    Germany is now leading the way in attacking part of the problem. Motor vehicles are thought to contribute significantly to the pollution of the atmosphere. ’The by-products of motor vehicle emissions are considered dangerous to plants and humans as well. In order to clean up motor vehicle emissions, all new cars in Germany must now meet new emission standards and be fitted with a device called catalytic converter. Use of the converter requires people to switch to lead-free petrol. This might explain why the Europeans are reluctant tofollow Germany’s lead in cleaning up its motor vehicle emission. It’s unlikely that Germany will force her European neighbors to change to lead-free petrol. The reason is that though her neighbors may be slow in cleaning up their smoke stacks, they will have to comply with the new motor vehicle requirements, if they want the wealthy German tourists driving across their borders. Certainly, the menace of acid rain knows no borders because it gathers in the rain clouds and goes with the prevailing winds. So Canada’s lakes die from America’s pollution. Germany’s trees die from her next-door neighbors. Sweden’s lakes fall victim to Britain’s industry. And there are many similar examples. And I won’t go into them because of time constraint. Like Germany, the United States also introduced strict clean air-controls on motor vehicle emissions in the mid-70s as part of their efforts to reduce acid rain. But throughout the northern hemisphere it’s agreed that such measures, though important, will be of minimal effect. If we are to save what’s left of the forests and lakes in the world, a strict international emission standard must be uniformly imposed on industry. However, it’s unlikely that will be agreed before many more hectares of precious forests are destroyed.