The use of quantitative models to assess long-term climate–vegetation dynamics – A case study from the northern Scandinavian Mountains

Abstract

Quantitative vegetation models combined with fossil pollen records have large potentials for assessing long-term vegetation dynamics. In this study, vegetation cover as a function of July temperatures was modelled for the Dividalen valley area situated in the northern Scandinavian Mountains. Site-specific pollen deposition values of the two dominating tree species pine and birch were simulated and compared with empirical fossil pollen values. The applied vegetation model could not explain the forest dynamics prior to 7400 cal. BP, although after this date, the forest seemed to have received a modern structure, and summer temperatures could potentially explain the long-term variations in forest cover. The most extensive forest cover occurred c. 7400–3800 cal. BP, corresponding to July temperatures of 0.5–1°C above the present. The approach proved sensitive to both site location and data quality. Careful site-selection is of importance for the application, and pollen accumulation rates are to be preferred as pollen percentage values proved problematic.