Evaluating the Potential of Vegetation Indices in Detecting Drought Impact Using Remote Sensing Data in a Mediterranean Pinewood

Abstract

The Mediterranean ecosystem represents an important natural resource, being able to produce ecosystem services, has both economic and social repercussions, especially if located in urban and peri-urban areas. In the last decades, increased forest vulnerability is being reflected in a larger number of severe decline episodes associated mainly with drought conditions. In this context, the Mediterranean area shows high forest vulnerability and a subsequent decline in its natural renewal rate. In this context, the objective of this research is to evaluate the different vegetation indices to monitor the effect of drought on the health of the Castelporziano pine wood. For this purpose, we used the NDVI, NDII and NMDI, provided by ESA Sentinel-2 images and field observations, to monitor the health status of a historic pinewood that has recently been affected by a rapid spread of parasites (Tomicus destruens Woll.). The application of these indices, on the scale of the entire pinewood, showed that the NDVI and NDII indices differentiate better the changes in vegetative health status for the observed period than the NMDI. Moreover, NDVI and NDII were applied, based on the classifications made, to volume and age classes. Ultimately, these preliminary results require further studies to better understand the potential and limiting factors of the indices used in monitoring pinewoods under stress due to aridity.