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Street Trees Provide an Opportunity to Mitigate Urban Heat and Reduce Risk of High Heat Exposure
Figure 1. Study area for this work, which is part of the Greening Research in Tacoma (GRIT) project, is located in South Tacoma, Washington, USA, shown by the black square on global map, where solar radiation shields (photographed) containing temperature loggers were installed on utility poles. Here we report on temperature data from loggers at 46 locations throughout the neighborhood (blue dots) during summer 2022. Climate change is exacerbating the need for urban greening and the associated environmental and human well-being benefits. Trees can help mitigate urban heat, but more detailed understanding of cooling effects of green infrastructure are needed to guide management decisions and deploy trees as effective and equitable climate adaptation infrastructure. We investigated how urban trees affect summer air temperature along sidewalks within a neighborhood of Tacoma, Washington, USA, and to what extent urban trees reduce risks of high summer temperatures (i.e., the levels regulated by state outdoor heat exposure rules intended to reduce heat-related illnesses). Air temperature varied by 2.57 °C, on average, across our study area, and the probability of daytime temperatures exceeding regulated high temperature thresholds was up to five times greater in locations with no canopy cover within 10 m compared to those with 100% cover. Air temperatures decreased linearly with increasing cover within 10 m, suggesting that every unit of added tree cover can help cool the air. Our findings highlight the value of trees in mitigating urban heat, especially given expected warming with climate change. Protecting existing urban trees and increasing tree cover (e.g., by planting street trees), are important actions to enhance climate change resilience of urban areas.
Read moreNature and Mental Health: An Ecosystem Service Perspective
Figure 1. A conceptual model for mental health as an ecosystem service. A growing body of empirical evidence is revealing the value of nature experience for mental health. With rapid urbanization and declines in human contact with nature globally, crucial decisions must be made about how to preserve and enhance opportunities for nature experience. Here, we first provide points of consensus across the natural, social, and health sciences on the impacts of nature experience on cognitive functioning, emotional well-being, and other dimensions of mental health. We then show how ecosystem service assessments can be expanded to include mental health, and provide a heuristic, conceptual model for doing so.
Read moreNature Contact and Human Health: A Research Agenda
Figure 1. A spectrum of forms of nature contact. Background At a time of increasing disconnectedness from nature, scientific interest in the potential health benefits of nature contact has grown. Research in recent decades has yielded substantial evidence, but large gaps remain in our understanding. Objectives We propose a research agenda on nature contact and health, identifying principal domains of research and key questions that, if answered, would provide the basis for evidence-based public health interventions. Discussion We identify research questions in seven domains: a) mechanistic biomedical studies; b) exposure science; c) epidemiology of health benefits; d) diversity and equity considerations; e) technological nature; f) economic and policy studies; and g) implementation science. Conclusions Nature contact may offer a range of human health benefits. Although much evidence is already available, much remains unknown. A robust research effort, guided by a focus on key unanswered questions, has the potential to yield high-impact, consequential public health insights.
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