Effects of atmospheric and climate change at the timberline of the Central European Alps

Les Ulis

EDP Sciences

2009

S. 402-412

6 Abb., zahlr. Lit. Ang.

Bandaufführung

158579

Annals of Forest Science, S. 402-412

This review considers potential effects of atmospheric change and climate warming within the timberline ecotone of the Central European Alps. After focusing on the impacts of ozone (O3)and rising atmospheric CO2 concentration, effects of climate warming on the carbon and water balanceof timberline trees and forests will be outlined towards conclusions about changes in tree growth andtreeline dynamics. Presently, ambient ground-level O3 concentrations do not exert crucial stress on adult conifers at the timberline of the Central European Alps. In response to elevated atmospheric CO2 Larix decidua showed growth increase, whereas no such response was found in Pinus uncinata. Overall climate warming appears as the factor responsible for the observed growth stimulation of timberline trees. Increased seedling re-establishment in the Central European Alps however, resulted from invasion into potential habitats rather than upward migration due to climate change, although seedlings will only reach tree size upon successful coupling with the atmosphere and thus loosing the beneficial microclimate of low stature vegetation. In conclusion, future climate extremes are more likely than the gradual temperature increase to control treeline dynamics in the Central European Alps.