Linking satellite-derived vegetation health parameters to arborist ground observations in urban environment.

Trees in cities play a crucial role in regulating the urban environment and promoting citizens’ health and well-being. However, trees are under constant stress, causing reduction of provided ecosystem services, faster decline, and a need for intensive maintenance. Here, we test parameters derived from Enhanced Vegetation Index (EVI) that enables effective health and vitality assessment through satellite observation in two pilot cities (Lisbon and Copenhagen), and link them to arboricultural terms using data from ground surveys. Results show differences in the interpretation of EVI in contrasting environments. In Copenhagen, trees respond to stress through changes in chlorophyll content expressed by EVI, whereas in Lisbon, EVI primarily reflects variations in vitality. The newly introduced composite stress index shows strong agreement with arborist observations. These results highlight the EVI as a promising and cost-effective tool for assessing the health status of urban greenery, reducing the need for frequent and expensive ground observations.