Web Application Based on Sentinel-2 Satellite Imagery for Water Stress Detection and Monitoring in Poplar Plantations

Clonal poplar plantations under conditions of water stress are more susceptible to pests and diseases, in addition to having lower growth rates than in optimal conditions of water availability. Likewise, water management is essential to guarantee responsible and sustainable wood production, with a minimum water footprint. The aim of this paper was to develop a user-friendly online system based on satellite imagery to detect and monitor damages caused by water stress in poplar plantations, so it could be used by the poplar owners/managers without previous knowledge of remote sensing. PoplarAlert is a free online web application which was developed using Sentinel-2 MSI imagery, Google Earth Engine, Python. It allows the user to obtain, through the application, clear and immediate information on the probability that damage due to water stress has occurred (in- formation in the form of an image, graph, vector or table). In addition, this tool allows the temporary reconstruction of a damage that is detected (to go back in time and try to identify the trigger). The results of testing it in two different plantations confirmed the capability of PoplarAlert to detect water stress once there was some leaf loss and/or drier/yellower leaves still on the tree (previously or during the leaf loss).