Restorative Effects of Blue-Green Spaces on the Elderly’s Mental Health Under Seasonal Variations: An Empirical Study in Changchun from the Spatial-Behavioral Perspective

While society pays more attention to people’s mental health, there are not sufficient studies on the restorative effects of blue-green spaces on that of special groups of people under seasonal variations. Based on field works and following the route of restorative effects, analytic discussions, and planning implications, this study examines and compares the restorative effects of blue-green spaces on the elderly’s mental health under seasonal variations and explores the relations among spaces, behaviors, and restorative effects from the spatial-behavioral perspective. It divides the restorative effects of blue-green spaces on mental health into the two categories of cognitive recovery and emotional improvement and verifies the restorative effects of ten spatial factors and four behavioral factors through digital span tests and emotional tests. The study indicates that throughout a year, blue-green spaces consistently exhibit restorative effects on the elderly’s mental health, which are stronger in both cognitive recovery and emotional improvement in non-winter seasons rather than winter. In terms of spatial factors, vegetations or evergreen vegetations exhibit the strongest effects regardless of seasonal variations. Ice and snow sculptures rank second in winter, followed respectively by structures in cognitive recovery and water bodies in emotional improvement; while in non-winter seasons, water accessibility, structures, and water bodies rank in succession. Among the spatial factors that are supportive to behaviors, the length of main pathways exhibits the strongest, while the area of plazas shows the smallest, and water bodies always show significant effects no matter their size. In terms of behavioral factors, the duration of stay shows the strongest effects in cognitive recovery in all seasons, while social attribute and exercise intensity show remarkable effects on emotional improvement in winter and the duration of stay and social attribute in non-winter seasons. The purpose of behaviors shows no significance in term of restorative effects. Furthermore, this study reveals that the restorative effects of behavioral factors vary significantly under different spatial factors and provides planning suggestions to facilitate behaviors through optimizing spatial factors.