Analisi delle variazioni di produttività di tre nuclei di faggeta aventi carattere di vetustà
Author(s)
Alessandrini, Alfredo
Date Issued
February 26, 2009
Type
Doctoral Thesis
Abstract
Aim: Understand how the recent climatic changes are impacting the basal area increment (an indicator of forest productivity) of beech woods in Italy. In recent decades there has been an increase in temperature; the effects on forest growth is widely debated, especially in Mediterranean areas, where some authors described a reduction in stand productivity in consequence of increasing drought (the factor limiting woods
productivity).
Materials and methods: Productivity of old-growth beech forests in the Mediterranean Basin was measured by average stem basal area increment (BAI) of dominant trees at three mountain sites in the Italian Apennines. Basal area increment
(BAI) was used to estimate productivity. A dataset of gridded temperatures and
precipitation series was used for the study of climatic factors controlling productivity.
Drought at the two sites was quantified by the self-calibrated Palmer Moisture Anomaly
Index (Z-index), and by the self-calibrating Palmer Drought Severity Index (PDSI) for
summer (June through August) and the growing season (May through September).
Indices derived from satellite images were also compared to productivity data: NDVI,Normalized difference vegetation index, and FAPAR, Fraction of Absorbed Photosynthetically Active Radiation.
Results: The results obtained helped to clarify the climatic signals that regulate changes in beech woods productivity. Dendroclimatic analyses revealed a moisture limitation in beech BAI at the interannual (water availability measured by Z-index) and decadal timescales (water availability measured by PDSI). This impact was clearly detected by FAPAR, reconciling the observed BAI with remote sensing data.
Conclusion: These findings have implications for modelling tree growth at the landscape level in relation to forest management options and carbon cycling estimates,especially with regard to the impact of climate variability.
Additional information
Dottorato di ricerca in Scienze e tecnologie per la gestione forestale e ambientale
Subjects
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