How Long Should I spend in Nature Today? Evidence for a 45-Minute Observed Breakpoint in Psychological Ecosystem Services During Single-Visit Urban Green-Space Experiences

Urban green spaces provide psychological ecosystem services, yet the combined roles of exposure duration and landscape perceptions remain underspecified in landscape-related research. To bridge this knowledge gap, we conducted a theory-informed, cross-sectional field survey using on-site data and analyzed 2,077 valid questionnaires. Landscape perceptions were positively associated with landscape preference and positive affect (PA) but inversely related to negative affect (NA); perceived danger was positively associated with NA. The decision-tree models of the data-driven split indicated 45 min per visit as the first split point. For <45-min visits, PA was associated with perceived restorativeness, complexity, legibility, and biophilic design; for longer visits, PA was primarily linked to perceived restorativeness. When duration was categorized by 15-min increments, for 46 to 60-min visits, ratings were higher in positive landscape perceptions, preference, and PA; NA was not duration-dependent. Our findings support promoting restorative experiences, biophilic landscape features, and well-being in urban green spaces.