Young potted trees are a way to green urban environments in areas where permanent plantations are not possible. Despite their small size, in places with otherwise limited green coverage, they can be an important source of ecosystem services: esthetics, localized shading and cooling effect and removal of pollutants to name but a few.  To provide the desired services, however, the trees must be in good health and function normally despite their restricted conditions. For example, with relatively small rooting systems and detachment from the soil, the water provision of these trees relies mainly on irrigation.

Throughout the 2023 growing season, we will continuously follow the transpiration of 20 potted trees in the Quartier de Spectacles area of Montreal using sap flow sensors. Additionally, we will perform bi-weekly point measurements on soil moisture, tree water status (using leaf water potential measurements) and tree photosynthetic efficiency (using chlorophyll fluorescence measurements), both before and after irrigation of the pots. With these measurements, we can then follow the potential drought stress experienced by the potted trees before irrigation and analyze trends in their transpiration and experienced stress over the growing season.

In addition, the data on tree transpiration and its calculated effects on air cooling and pollution removal are available to the public in real time through QR codes at each tree.  The QR code also leads to more information on the specific characteristic of the tree species in question.