During the 1980s, the literature on forest health was dominated by accounts of a new type of decline that was believed to be affecting trees throughout Europe. Initially, reports were confined to the conifers Norway spruce (Picea abies) and silver fir (Abies alba), but later reports (from the mid-1980s) also included broad-leaved trees. The first records of the problem came from Bavaria and Baden-Wiirttemberg in southern Germany, and problems were later reported from other areas in Germany (e.g., the Harz Mountains). Subsequently, reports of forest decline appeared from a variety of European countries, especially after the establishment of an international inventory of crown condition, which supposedly revealed both the massive extent of the decline and its rapid spread through Europe. "Acid rain" was usually considered to be the culprit. The decline was believed to be different from the air pollution injury that had been observed in industrial areas since the nineteenth century. The pollution injury was generally restricted to specific areas in the neighborhood of major sources of pollution and was characterized by direct foliar injury.