Understanding tree species response to urban heat using high resolution remote sensing

利用高分辨率遥感了解树种对城市热量的响应

• 批准号: 1951647
• 负责人: Michael Alonzo
• 金额: $ 41.67万
• 依托单位: American University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1951647&HistoricalAwards=false
• 关键词: Understanding; tree; species; response; urban

Movement of water from the ground up to tree leaf surfaces, where it evaporates, is an important means by which green infrastructure cools cities. This water movement—or transpiration—is also linked to a tree’s ability to store carbon via photosynthesis. However, it is not well understood how different tree species respond to urban heat with respect to maintenance of transpiration at high temperatures or shifts in the dates of leaf development and leaf fall. Thus, cities do not have adequate information to choose the species that are best equipped to thrive under stressful conditions and bolster climate resilience under warming. This project uses drone and satellite imagery analysis to observe these responses in a manner only previously possible under laboratory conditions. This project will increase our understanding of how trees in an urban environment can help to mitigate the warming of cities though the cooling impact of trees.Information on how species and planting site (e.g., downtown street tree, suburban park tree) influence urban forest transpiration is lacking, in part because it is difficult to account for a city’s high degree of land cover heterogeneity at fine spatial scale. This project accounts for rapid changes in tree response to heat over space and time through use of high-resolution imagery analysis. Drone measurements of leaf temperature and chemistry will be acquired multiple times per day to examine the extent to which photosynthesis and transpiration track one another or diverge. Weekly satellite imagery capable of measuring leaf abundance at the individual tree scale across a large city will be used to assess changes in urban forest start and end of season, a fundamental control on seasonal transpiration. These analyses are among the first to provide observational evidence of how urban tree function may be altered by increased heat at daily and seasonal increments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

水从地面向上运动到树叶表面，在那里蒸发，是绿色基础设施为城市降温的重要手段。这种水的运动或蒸腾作用也与树木通过光合作用储存碳的能力有关。然而，人们还不太清楚不同树种如何对城市高温做出反应，以维持高温下的蒸腾作用或叶片发育和落叶日期的变化。因此，城市没有足够的信息来选择最适合在压力条件下茁壮成长的物种，并在变暖的情况下增强气候适应能力。该项目使用无人驾驶飞机和卫星图像分析，以一种以前只有在实验室条件下才能实现的方式观察这些反应。这个项目将增加我们对城市环境中的树木如何通过树木的降温作用来帮助缓解城市变暖的理解。关于树木物种和种植地点的信息（例如，城市森林蒸腾作用的影响是缺乏的，部分原因是很难在精细的空间尺度上解释城市高度的土地覆盖异质性。该项目通过使用高分辨率图像分析来解释树木对热的反应在空间和时间上的快速变化。每天将多次获得叶片温度和化学成分的无人机测量值，以检查光合作用和蒸腾作用相互跟踪或发散的程度。将利用能够在一个大城市的每棵树尺度上测量树叶丰富度的每周卫星图像来评估城市森林季节开始和结束时的变化，这是对季节性蒸腾作用的基本控制。这些分析是第一个提供观测证据的城市树木功能如何可能会改变增加热量在日常和季节性increment.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

项目成果

Canopy composition drives variability in urban growing season length more than the heat island effect

冠层组成对城市生长季节长度变化的影响大于热岛效应

• DOI: 10.1016/j.scitotenv.2023.163818
• 发表时间: 2023
• 期刊: Science of The Total Environment
• 影响因子: 9.8
• 作者: Alonzo, Michael;Baker, Matthew E.;Caplan, Joshua S.;Williams, Avery;Elmore, Andrew J.
• 通讯作者: Elmore, Andrew J.

Spatial configuration and time of day impact the magnitude of urban tree canopy cooling

• DOI: 10.1088/1748-9326/ac12f2
• 发表时间: 2021
• 期刊: Environmental Research Letters
• 影响因子: 6.7
• 作者: M. Alonzo;M. Baker;Yuemeng Gao;V. Shandas