Air pollutants provide environmental conditions that drastically differ in many respects from those to which forest trees are naturally adapted. Leading experts in the field here consider these questions of immediate relevance arising from the changing environment: (1) Do air pollutants introduce effects of selection that differ from those known for populations that are not subject to such stress conditions? (2) If air pollutants introduce quantitatively or even qualitatively novel selective effects, which consequences might arise from the adaptation of forest tree populations to the present conditions as well as for the preservation of adaptability to future conditions? In addition to these questions, concepts for preservation of genetic resources are discussed.

1: Methods of sampling and genetic analysis

The attribution of phenotypic variation to genetic or environmental variation in ecological studies
Isoenzymes, indicators of environmental impacts on plants or environmentally stable gene markers?
2: Variation in response to pollutants
Variation in and natural selection for air pollution tolerances in trees
Structure and first results of a research program on ecological genetics of air pollution effects in Norway spruce
Response of Picea abies (L.) Karst. provenances to aluminum in hydroponics
Variation in needle wax degradation in two silver fir provenances differentiated by tolerance to air pollution
Natural variation in sensitivity of reproductive processes in some boreal forest trees to acidity
Effects of air pollutants on reproductive processes of poplar (Populus spp.) and Scots pine (Pinus sylvestris L.)
3: Selection effects of pollutants
Genetic studies in populations of Silene cucubalus occurring on various polluted and unpolluted areas
Studies of Scots pine populations in polluted and clean areas
Genetic implications of environmental stress in adult forest stands of Fagus sylvatica L.
Selection effects of air pollution in Norway spruce (Picea abies) populations
4: Preservation of genetic resources
The importance of genetic multiplicity for tolerance of atmospheric pollution
Gene resources and gene conservation in forest trees: General concepts
Measures for the conservation of forest gene resources in the Federal Republic of Germany
Implications of genetic effects of air pollution on forest ecosystems - Knowledge gaps -.