Variations in trends of temperature and its influence on tree growth in the Tuscan Apennines

The evidence of climate change occurred in the last century, causes significant alterations to the environment. The adaptation of plants is a particularly important aspect of it and contributes to assess the variations in biodiversity to expect in the near future in the attempt of understanding the possible consequences. In this research, some significant forest areas of the Tuscan Apennines, which are featured by a complex and varied territory from a climatic point of view, have been taken into consideration. Four historical weather stations were considered, in order to verify climate trends and their mutual correlations. In-depth analyses were carried out to identify climate trends and check whether there are recurring periods in the climate, as seemed to be highlighted by previous studies on silver fir forests. The results were surprising as inhomogeneous distribution of temperatures during time between the different sites sampled was observed, and clustering of the sites showed variability through space and time. In addition, a return period of 6–7 years was identified in the historical temperature series through Fourier analysis, outlining a cyclical trend of the same; that could be reflected in the growth trends of trees. Furthermore the analysis revealed that the use of master series of the climate variable as representative of trends across the study area can lead to not detecting relevant information relating to climate/tree growth relationships both at the forest landscape level and at the forest unit level, thus affecting the accuracy and validity of forest management plans.