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The feasibility of detecting trees affected by the Pine Wood Nematode using remote sensing

On request of DG SANTE , the Joint Research Centre has conducted between November 2014 and April 2015 a pilot study to establish the feasibility of remote sensing based detection of trees affected by Pine Wood Nematode (PWN) in the 2.2 Mha buffer zone established along the Portuguese and Spanish border. JRC collected multiple types of remote sensing data, from both aircraft and satellites, and a range of sensors and resolutions over a 7000 ha study site in Spain in the winter of 2014-2015. The images were evaluated for their ability to distinguish a) between pine trees that appeared to have a healthy canopy, and those showing decline, and b) between different levels of canopy decline, in terms of defoliation, decolouration and die-off. Detailed analysis of the imagery showed that when properly processed, remote sensing observations, particularly at high spatial and spectral resolution from aircraft, do permit the identification of pine trees showing canopy decline. The ability to detect individual tree crowns, and varying levels of canopy decline, varied with the image resolution, the type of sensor used to acquire the data, and the level of processing of the data. Based on the findings of this study the report spells out a set of technical recommendations for the operational monitoring of tree canopy health over large areas in the context of tree pest oubreaks.
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