A Further Contribution to the Problem of the Spread of Spruce (Picea abies (L.) Karst.) in Fennoscandia

The available, stratigraphically well-founded, radiocarbon dates for identifiable stages of the regional spread of spruce (Picea abies (L.) Karst.) within Fennoscandia, published during the last five years (to 1975), have been added to a previously published map. The resulting temporal and spatial pattern is compared with Paterson's map of the bioclimatic regions of Fennoscandia, which is based on meteorological data alone. The parallelisms found between these maps can be explained by reference to those seasonal ecological factors which favour seed survival, and the initial 2 to 3 years (the seedling stage) of spruce growth; rates of migration and human influences are still considered in general to be second-order factors in any explanation of the spread of spruce.