 The Germans call it vulture bin, meaning death of the forests. All over the world, large wooded areas, once lush and green, are now sickly and gray. Seeking reasons for this dramatic decline, scientists, including a group from NASA, have been studying the problem on Camelshump Mountain in Vermont. This photograph was taken from Camelshump in 1963. Here's what this same area looked like 20 years later. To find out why, NASA researchers have been gathering samples of dying trees on various parts of the mountain. There you go. Yeah, look at the chlorosis on this one. These samples, bagged and labeled in the field, were later be analyzed in area laboratories. One theory why forests are dying is what's popularly referred to as acid rain. Pollutants caused by the burning of fossil fuels get into the atmosphere, are moved around our planet by air currents, and fall back to Earth in the rain, absorbed by plants and trees. Based on their analysis of the samples collected on Camelshump, NASA scientists are not convinced that acid rain is the sole cause of the problem. But they do think it's a factor. Dr. Barry Rock explained. Some rainfall measurements on Camelshump have been just horrendous. We're approaching vinegar, we're approaching battery acid in terms of the acidity. Certainly that's got to have some effect on vegetation. Specially equipped air plant and satellites are also being used in the investigation to produce imagery of the study sites. Because the health of a plant or tree determines how it shows up in these images, they provide a very accurate way of discovering, mapping and monitoring damaged areas. NASA scientists now plan to use even more advanced airborne instruments to detect the very first stages of forest decline before it becomes obvious. Then we have some hope of being able to treat the patient before it is terminally ill. Small Vermont sawmills and the worldwide lumber industry in general could soon begin feeling the impact of bolstering. But as Dr. Rock points out, the problem really goes beyond economic concerns. The spruce trees on Camelshump and in the black forest are very sensitive indicators of stress and they may well end up being the canary in the mine shaft. And since we can't easily get out of our particular mine shaft, we're going to have to start looking at means of improving the atmospheric conditions. NASA's damage assessment effort, looking at the trees to save the forests.