The cooling effects of urban parks, which form “Park Cool Island” (PCI), can help decrease land surface temperature (LST) and mitigate urban heat island (UHI) effects. PCI intensity largely depends on the characteristics of urban parks. The relationship between PCI intensity and urban park characteristics such as urban park size has been well documented. However, it is still unclear how urban forest structures in parks affect PCI intensity and particularly whether the relationship changes across seasons. In this study, PCI intensity for 33 parks in Changchun, China was obtained from Landsat-5 Thematic Mapper (TM) data and then correlated with urban park characteristics such as the size derived from “Systeme Probatoire d’Observation dela Tarre” (SPOT) satellite data and the forest structures of parks derived from the field-based survey to uncover the relationship between urban park characteristics and PCI intensity. Our results suggested that (1) The PCI intensity varied across seasons and the cooling effect of parks in summer was higher than that in autumn. (2) The increase of urban park size was still an effective measure to mitigate UHI. However, urban park size was non-linearly correlated to PCI intensity. (3) Not only by increasing urban park size, but also by optimizing urban park shape and forest structures in parks can increase PCI intensity. (4) The relationship between PCI intensity and urban park characteristics changed across seasons and seasons should be considered when exploring the relationship between them. These findings can deepen the understanding of PCI formation and provide useful information for urban planners about how to design urban parks to maximize their PCI intensity and mitigate UHI effects

He X., Ren Z., An B., 2017. The tree-species-specific effect of forest bathing on perceived anxiety alleviation of young-adults in urban forests. Ann. For. Res. 60(2): 327-341.Abstract. Forest bathing, i.e. spending time in a forest to walk, view and breathe in a forest, can alleviate the mental depression of visitors, but the tree-species-specific effect of this function by the urban forest is unknown. In this study, sixty-nine university students (aged 19-22, male ratio: 38%) were recruited as participants to visit urban forests dominated by birch (Betula platyphylla Suk.), maple (Acer triflorum Komarov) and oak (Quercus mongolica Fisch. ex Ledeb) trees in a park at the center of Changchun City, Northeast China. In the maple forest only the anxiety from study interest was decreased, while the anxiety from employment pressure was alleviated to the most extent in the birch forest. Participants perceived more anxiety from lesson declined in the oak forest than in the birch forest. Body parameters of weight and age were correlated with the anti-anxiety scores. In the oak forest, female participants can perceive more anxiety alleviation than male participants. For university students, forest bathing in our study can promote their study interest. Forest bathing can be more effective to alleviate the anxiety of young adults with greater weight. The birch forest was recommended to be visited by students to alleviate the pressure of employment worry, and the oak forest was recommended to be visited by girls.