PhenoStras2022: A 2022 smartphone-based image and field phenology dataset for monitoring urban trees in Strasbourg, France

Urban trees provide critical ecosystem services but remain vulnerable to climate change and urban environmental stresses. To improve understanding of their phenological dynamics and support reproducible urban vegetation monitoring, PhenoStras2022 is introduced, a dataset based on non-destructive, low-cost (using a portable smartphone-based setup) ground-based observations. Data were collected throughout a complete phenological cycle in 2022 across 40 green sites in Strasbourg, France. Two types of photographic acquisitions were conducted: Digital Hemispherical Photography (DHP) and Front-View Photography (FVP), complemented by field-based phenological observations following a simplified BBCH scale. The dataset is organized to enable a range of applications, including remote sensing products validation and urban climate studies. PhenoStras2022 addresses the current lack of ground-based urban phenology data and provides a robust foundation for analysing seasonal patterns and the resilience of urban trees. It also promotes participatory science by offering an accessible, replicable acquisition protocol, contributing to the strengthening of phenological monitoring networks in the context of a changing climate.