The feasibility of detecting trees affected by the pine wood nematode using remote sensing

At the request of DG SANTE, the Joint Research Centre conducted a pilot study between November 2014 and April 2015 to establish the feasibility of the remote-sensing-based detection of trees affected by Pine Wood Nematode (PWN) in the 2.2 Mha buffer zone established along the Portugal-Spain border. The JRC collected multiple types of remote sensing data at various resolutions from a range of sensors on aircraft and satellites over a 7 000-ha study site in Spain during 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 properly processed remote sensing observations, particularly at high spatial and spectral resolution from aircraft, can help identify 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. This report uses the findings of the study to spell out a set of technical recommendations for the operational monitoring of tree canopy health over large areas in the context of tree pest outbreaks.