Seasonal aesthetic signatures of urban trees driven by phenological dynamics

Phenological dynamics in urban trees continuously reshape tree visual appearance and, consequently, the way people perceive scenic beauty, yet most aesthetic assessments rely on static snapshots that ignore seasonality. Here, we integrate one year of fortnightly phenological monitoring (February 2024 to January 2025) with a Scenic Beauty Estimation (SBE) to quantify seasonal aesthetic trajectories (“seasonal aesthetic signatures”) for twelve tree species widely used in urban landscaping on the campus of the Federal University of Viçosa, southeastern Brazil. Five individuals per species were monitored for vegetative and reproductive phenophases, and a photo-based online questionnaire (May to July 2024) assessed both whole-tree scenic beauty and isolated visual attributes, including flower colour, canopy shape, foliage density, and tree size. Attribute-level evaluations were standardised using the SBE procedure and rescaled to a common 1–5 range. These scores were coupled with phenological calendars to generate fortnightly composite visual indices, which were linearly calibrated against empirical SBE values to estimate continuous seasonal SBE curves for each species. Preferences consistently favoured light and bright flower colours (especially yellow), elliptical crown forms, denser canopies and larger tree size. Species differed markedly in temporal aesthetic behaviour: fully deciduous taxa with short, concentrated flowering produced high but brief aesthetic peaks and strong peak dependence, whereas species with prolonged or bimodal flowering showed smoother trajectories and greater aesthetic persistence. Evergreen species exhibited low annual amplitude and stable, near-constant curves, reinforcing visual continuity rather than episodic salience. Across species, seasonal variation was summarised using annual SBE amplitude, mean annual SBE, the proportion of negative-SBE fortnights, and peak dependence, revealing contrasting aesthetic preferences linked to phenological patterns. Overall, the results demonstrate that scenic beauty in urban trees is a temporal property structured by phenological preference, offering a practical, phenology-informed framework to support species selection and planting design that explicitly accounts for seasonal performance.