issue 184 - June 1988
The forest is dying
Not only is acid rain killing trees but it seems to have
made us blind as well, as Chris Rose reports.
It was not foresters who first noticed that the forests of central Europe were dying, but parents and children who went each year to the Black Forest in West Germany to collect silver-fir foliage for Christmas decorations. 'At one time sale of these trimmings more than paid our management costs,' a forester told me. 'Then when the people saw they were discolored they stopped coming and we began to realize something was wrong.'
The forest killer was a cocktail of pollutants commonly known as 'acid rain'; a by-product of the air pollution from car exhausts and industrial processing. The forest decline this causes is called waldsterben or the 'forest dying'. It appeared first in the richest and most powerful economies of Europe, striking down firs and spruce in the playground of West Germany - the Black Forest and the Alps of Bavaria. In the past eight years it has also been recognized in most of the rest of northern Europe, Eastern Canada, the US and even Japan. There, downwind of Tokyo and the industrial-technological complex which stretches from Kawasaki to the sea port of Yokohama, the airborne chemical signature of Japanese industry has left the venerated Japanese cedars thinning and tattered over 20,000 square miles of countryside.
In conifer trees the needles fall years early, often first turning a sickly yellow indicating a shortage of essential metals such as magnesium. As the decline progresses the tree loses its ability to feed itself through photosynthesis (because the leaf area is reduced) and in its weakened state falls victim to diseases. In deciduous species such as the beech and oak the pattern is similar. Official surveys show that over half of Britain's broadleaved trees have lost a quarter or more of their leaf area. In fact Britain's oak and beech are probably the most damaged in Europe.
Like the much-cited canary in the coal-mine, the dying forests are potent indicators of what is to become of us, for the chemicals that cause acid rain also attack people. Water on already slightly acid rocks and sands becomes more acid with pollution, releasing toxic metals such as cadmium, lead, mercury and aluminium. This last, it is claimed, accounts for the high rates of Alzheimer's disease (senile dementia) in southern Norway.
Vehicle exhausts spew out oxides of nitrogen and hydrocarbons which include cancer-inducing chemicals. Diesel is particularly rich in such pollution. Together in the air, these chemicals react in sunlight to form ozone, a substance which is essential outside the atmosphere where it protects the earth from harmful ultra-violet rays. Inside the atmosphere, however, it is a pollutant which eats through leaf-cell walls, making them permeable to acidic rainfall, and leaching out key nutrients. Ozone also attacks the lungs of mammals and birds. The American bald eagle used as a mascot at the Los Angeles Olympics died from lung disease caused by air pollution.
Parents' campaigning organizations in Austria and West Germany have long believed that cot-deaths could be associated with industrial air pollution, just as people who died in the London smogs are now known to have suffered severe lung irritation from sulphuric acid particles. Similarly the US Clean Air Scientific Advisory Committee concludes that current air quality standards do not protect asthmatics. This finding may lead to amendment of the Clean Air Act, requiring substantial extra amounts of sulphur to be cleaned from power station gases.
The issue of air pollution and health is one which should concern us all. It is secondary smoking on the grandest of scales. The advent of tall chimneys, the widespread substitution of electricity for coal as a heating source for houses, and the rapid increase in car ownership and road transport have meant that air pollution once concentrated in urban areas is now spread thinly over the previously clean countryside. Ice cores analyzed from the Arctic and Antarctic show that eventually it reaches there too.
Only recently have the effects of acid rain on trees begun to be recognized, which may be one reason why the implications of acid rain for humans have not really hit home. As Canadian Gilles Gagnon wrote in 1986: 'Each year the beauty of the forest is somewhat diminished but one gets used to it and finds it natural to see trees withering along the roadside'. The same could be said of almost every country in which the insidious decline has taken hold.
When the blight first started to be recognized in West Germany, slogans were daubed on the rocks of the worst affected Black Forest hillsides. 'Do not weep forest,' said one, 'the desert will not last forever'. Others referred to the Christmas carol, Oh Tannenbaum, which celebrates the beauty of the silver fir tree, a tree which not only occupies a central place in German folk-mythology but has been hardest hit by waldsterben. Yet within a year or so, the trees were being felled and others planted. After all, they look healthy. The signs were scrubbed from the rocks at the request of the local hoteliers. Acid rain and dying forests, they said, were bad for business. If it couldn't be cured then perhaps it should at least be denied.
The prospect of a civilization which can happily accept the Black Forest without trees is more than unsettling. On this basis attacks of tree blindness become an act of mass delusion as society turns its back on an apparently insoluble problem. The question is whether we open our eyes before the delusion becomes suicidal.
Chris Rose is an ecologist who has worked for the World Wildlife Fund, Greenpeace and Friends of the Earth.
1 Friends of the Earth Dieback Survey, Final Report, page 1.