Impacts of urban environment on the eco-physiological responses of trees: Tree-Talker (TT) new devices for the monitoring of trees

Urban ecosystems will become increasingly important in the coming years. Urban trees are likely to increase in importance to society as their value in enhancing people's sense of well-being as well as the direct economic impacts are increasingly recognized. Urban forest monitoring data are essential to assess the impacts of tree planting campaigns and management programs. Tree-Talker (TT) is a device based ton the Internet of Things (IoT) technology for the monitoring of trees physical and physiological conditions. The TT allows the monitoring of (i) multispectral measurements of the sunlight transmitted through the canopy in 12 bands across the visible and near infra-red spectra; (ii) sap flow, as indicator of tree transpiration and functionality of xylem transport; (iii) tree radial growth thanks to its infrared based distance sensor as indicator of carbon allocation in biomass; (iv) xylem moisture content as indicator of hydraulic functionality; and (v) tree stability parameters to allow real time forecast of potential tree fallings. The TT can also measure physical variables of the environment such as the temperature and air humidity. This device is connected to a LoRa radio network and a gateway is connected with the cloud. In this work, we evaluated the performance of different trees in Moscow city and assessed the differences in phenology, growth and transpiration across different species, different tree ages and different exposure to air pollution. This work contributes to accurate quantification of urban tree performance, helping urban managers make data-driven decisions.