The article deals with the relationships between the growth of trees and the condition of the crowns in the Vosges, the Jura (French and Swiss), the Swiss Plateau, some Swiss and Italiand Alpine regions and the most important forest sectors of Baden-Württemberg. The studies are based on dendrometric data and observations of crowns made at a large number of sites. These relationships vary greatly according to the trees and the conditions. They are greatly influenced by the social stratification within the stands. There is not one but many "normal conditions" depending on species, age, site, climatic conditions and silvicultural management. The major role is demonstrated of rainfall and temperature, during the period 1920-1986, in the determination of years or series of years marked by very low increments. Overall, particularly on poor an intermediate sites, there is a clear increase in productivity level both for spruce and fir. This phenomenon could imply one or several of the following causes: improved mineralisation, increased atmospheric CO₂ , better climatic conditions, better silvicultural treatment. Finally, the authors propose various research objectives and make recommendations for the improvement of dendroecological studies.