Assessment and Examination of Coastal Vegetation Deterioration by Means of Landsat TM Data

Abstract

The potential of remote sensing techniques for monitoring natural and agricultural vegetation has already been assessed in a great number of works. The present study is focused on the use of Landsat 5 Thematic Mapper (TM) data as a powerful and efficient means for providing information about a case of coastal vegetation deterioration in Tuscany.

This phenomenon, dating back about twenty-five years ago, mainly concerns the pine plantation which covers the plain south of the outlet of the Ombrone river. In the last forty years this zone has also been affected by strong coastal erosion. The almost contemporaneous occurrence of the two phenomena, as well as the geographical distribution of the disease and some morpho-physiological features of the injured plants, has led to the formulation of an hypothesis which identifies the infiltration of marine salt water into the phreatic surface below the pine wood as the main cause of the deterioration.

In this context, TM data not only provide precise and up-to-date information about the spatial distribution of the disease, but also give a straightforward means for quantitatively assessing vegetation conditions on a local scale (30 - 50m.), The latter parameter has been related to the likely causative agent of the injury, i.e., the presence of salt water in the pine wood soil. The results of the investigation confirm the working hypothesis and testify to the actual utility of high resolution satellite data in these situations.