Friday April 26, 2013. 03:30 pm. GUGG 205
Dendroecological networks allow historical ecologists to investigate the effect of environmental factors on forest ecosystems over years to millennia and from watershed to continental regions. A network of tree-ring site chronologies from beech populations sampled at different elevations within two different bioclimatic regions (Alps vs Apennines) were used to define beech bioclimatic distribution and for investigating tree response to climate. Climatic signals revealed the separation between the Mediterranean and the Alpine regions, whose spatial boundary was a function of summer drought control on growth. Within each region, elevation regulates climatic responses, as it controls both thermal regime and growing season onset and duration. Fagus sylvatica L. populations were arranged along three altitudinal bioclimatic zones: low-elevation, mountain, and high-mountain. Average Basal Area Increment (BAI), a common indicator of tree productivity, showed diverging trends for bioclimatic and altitudinal zones. The greatest lifespan was observed in old-growth high-mountain populations because of slower growth due to a shorter growing season in combination with growth suppression during the initial development stages in the understory (i.e. at the youngest cambial ages). Finally, investigations of growth patterns in this extensive network allowed the refinement of boundary line methods for identifying growth releases in beech ecosystems.
Geography colloquium series was made possible by the generous support from The Beirne Carter Foundation.