EGU2020-17113, updated on 08 Jan 2024
https://doi.org/10.5194/egusphere-egu2020-17113
EGU General Assembly 2020
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Assessing and monitoring the vulnerability to drought and climate anomalies of Mediterranenan oak forests by using NDVI

Maria Castellaneta1, Angelo Rita1, J. Julio Camarero2, Michele Colangelo1,2, Angelo Nolè1, and Francesco Ripullone1
Maria Castellaneta et al.
  • 1Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, Università della Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy (maria.castellaneta@unibas.it)
  • 2Instituto Pirenaico de Ecología (IPE‐CSIC), Avda. Montañana 1005, 50192 Zaragoza, Spain

Several die-off episodes related to heat weaves and drought spells have evidenced the high vulnerability of Mediterranean oak forests. These events consisted in the loss in tree vitality and manifested as growths decline, elevated crown transparency (defoliation) and rising tree mortality rate. In this context, the changes in vegetation productivity and canopy greenness may represent valuable proxies to analyze how extreme climatic events trigger forest die-off. Such changes in vegetation status may be analyzed using remote-sensing data, specifically multi-temporal spectral information. For instance, the Normalized Difference Vegetation Index (NDVI) measures changes in vegetation greenness and is a proxy of changes in leaf area index (LAI), forest aboveground biomass and productivity. In this study, we analyzed the temporal patterns of vegetation in three Mediterranean oak forests showing recent die-off in response to the 2017 severe summer drought. For this purpose, we used an open-source platform (Google Earth Engine) to extract collections of MODIS NDVI time-series from 2000 to 2019. The analysis of both NDVI trends and anomalies were used to infer differential patterns of vegetation phenology among sites comparing plots where most trees were declining and showed high defoliation (test) versus plots were most trees were considered healthy (ctrl) and showed low or no defoliation. Here we discuss: i) the likely offset in NDVI time-series between test- versus ctrl- sites; and ii) the impact of summer droughts  on NDVI.

Keywords: climate change, forest vulnerability, time series, remote sensing.

How to cite: Castellaneta, M., Rita, A., Camarero, J. J., Colangelo, M., Nolè, A., and Ripullone, F.: Assessing and monitoring the vulnerability to drought and climate anomalies of Mediterranenan oak forests by using NDVI, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17113, https://doi.org/10.5194/egusphere-egu2020-17113, 2020.

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