RTI International, 3040 E. Cornwallis Road, Research Triangle Park, NC, 27709, USA.
USDA Forest Service, Davey Institute, Davey Tree Expert Company, 5 Moon Library, SUNY-ESF, Syracuse, NY, 13210, USA.
J Environ Manage. 2022 Jan 1;301:113751. doi: 10.1016/j.jenvman.2021.113751. Epub 2021 Oct 7.
Heat-related mortality is one of the leading causes of weather-related deaths in the United States. With changing climates and an aging population, effective adaptive strategies to address public health and environmental justice issues associated with extreme heat will be increasingly important. One effective adaptive strategy for reducing heat-related mortality is increasing tree cover. Designing such a strategy requires decision-support tools that provide spatial and temporal information about impacts. We apply such a tool to estimate spatially and temporally explicit reductions in temperature and mortality associated with a 10% increase in tree cover in 10 U.S. cities with varying climatic, demographic, and land cover conditions. Two heat metrics were applied to represent tree impacts on moderately and extremely hot days (relative to historical conditions). Increasing tree cover by 10% reduced estimated heat-related mortality in cities significantly, with total impacts generally greatest in the most populated cities. Mortality reductions vary widely across cities, ranging from approximately 50 fewer deaths in Salt Lake City to about 3800 fewer deaths in New York City. This variation is due to differences in demographics, land cover, and local climatic conditions. In terms of per capita estimated impacts, hotter and drier cities experience higher percentage reductions in mortality due to increased tree cover across the season. Phoenix potentially benefits the most from increased tree cover, with an estimated 22% reduction in mortality from baseline levels. In cooler cities such as Minneapolis, trees can reduce mortality significantly on days that are extremely hot relative to historical conditions and therefore help mitigate impacts during heat wave conditions. Recent studies project highest increases in heat-related mortality in the cooler cities, so our findings have important implications for adaptation planning. Our estimated spatial and temporal distributions of mortality reductions for each city provide crucial information needed for promoting environmental justice and equity. More broadly, the methods and model can be applied by both urban planners and the public health community for designing targeted, effective policies to reduce heat-related mortality. Additionally, land use managers can use this information to optimize tree plantings. Public stakeholders can also use these impact estimates for advocacy.
热相关死亡是美国与天气相关死亡的主要原因之一。随着气候的变化和人口老龄化，采取有效的适应策略来解决与极端高温相关的公共卫生和环境正义问题将变得越来越重要。减少热相关死亡的一种有效适应策略是增加树木覆盖。设计这样的策略需要提供有关影响的空间和时间信息的决策支持工具。我们应用这样的工具来估计在美国十个气候、人口和土地覆盖条件不同的城市中，树木覆盖增加 10%对温度和死亡率的空间和时间上的明确减少。两种热指标被应用于代表树木对中度和极度炎热天气的影响（相对于历史条件）。在十个城市中，树木覆盖增加 10%显著降低了估计的热相关死亡率，总影响通常在人口最多的城市中最大。死亡率降低在城市之间差异很大，从盐湖城的约减少 50 人死亡到纽约市的约减少 3800 人死亡。这种差异是由于人口统计、土地覆盖和当地气候条件的差异造成的。就人均估计影响而言，在整个季节中，由于树木覆盖增加，较热和较干燥的城市的死亡率降低百分比更高。菲尼克斯因增加树木覆盖而受益最大，死亡率从基线水平降低了约 22%。在较凉爽的城市，如明尼阿波利斯，树木可以在与历史条件相比极热的日子显著降低死亡率，因此有助于缓解热浪条件下的影响。最近的研究预测，较凉爽城市的热相关死亡率将增加最多，因此我们的研究结果对适应规划具有重要意义。我们对每个城市的死亡率降低的空间和时间分布的估计提供了促进环境正义和公平所需的关键信息。更广泛地说，城市规划者和公共卫生界都可以采用这些方法和模型来设计有针对性、有效的政策，以降低热相关死亡率。此外，土地利用管理者可以利用这些信息来优化树木种植。公众利益相关者也可以使用这些影响估计值来进行宣传。
