Tree growth is a key mechanism driving carbon sequestration in forest ecosystems. Environmental conditions are important regulators of tree growth that can vary considerably between nearby urban and rural forests. For example, trees growing in cities often experience hotter and drier conditions than their rural counterparts while also being exposed to higher levels of light, pollution, and nutrient inputs. However, the extent to which these intrinsic differences in the growing conditions of trees in urban versus rural forests influence tree growth response to climate is not well known. In this study, we tested for differences in the climate sensitivity of tree growth between urban and rural forests along a latitudinal transect in the eastern United States that included Boston, Massachusetts, New York City, New York, and Baltimore, Maryland. Using dendrochronology analyses of tree cores from 55 white oak trees (Quercus alba), 55 red maple trees (Acer rubrum), and 41 red oak trees (Quercus rubra) we investigated the impacts of heat stress and water stress on the radial growth of individual trees. Across our three‐city study, we found that tree growth was more closely correlated with climate stress in the cooler climate cities of Boston and New York than in Baltimore. Furthermore, heat stress was a significant hindrance to tree growth in higher latitudes while the impacts of water stress appeared to be more evenly distributed across latitudes. We also found that the growth of oak trees, but not red maple trees, in the urban sites of Boston and New York City was more adversely impacted by heat stress than their rural counterparts, but we did not see these urban–rural differences in Maryland. Trees provide a wide range of important ecosystem services and increasing tree canopy cover was typically an important component of urban sustainability strategies. In light of our findings that urbanization can influence how tree growth responds to a warming climate, we suggest that municipalities consider these interactions when developing their tree‐planting palettes and when estimating the capacity of urban forests to contribute to broader sustainability goals in the future.

中文翻译：

---

城市化加剧了美国东部阔叶树的气候敏感性

树木生长是驱动森林生态系统固碳的关键机制。环境条件是树木生长的重要调节因素，附近城市和农村森林之间的差异很大。例如，与农村树木相比，在城市中生长的树木通常会经历更热和更干燥的条件，同时也会受到更高水平的光照、污染和养分输入。然而，城市森林与农村森林中树木生长条件的这些内在差异在多大程度上影响树木生长对气候的反应尚不清楚。在这项研究中，我们测试了美国东部纬度断面（包括马萨诸塞州波士顿、纽约市和马里兰州巴尔的摩）城市和农村森林之间树木生长对气候敏感性的差异。使用树木年代学分析 55 棵白橡树的树芯（白栎），55棵红枫树（红枫）和 41 棵红橡树（红栎）我们研究了热应激和水分胁迫对单棵树径向生长的影响。在我们的三个城市研究中，我们发现波士顿和纽约等气候凉爽的城市比巴尔的摩的树木生长与气候压力的相关性更密切。此外，热应激是高纬度地区树木生长的重大障碍，而水分胁迫的影响似乎在各纬度地区分布更为均匀。我们还发现，波士顿和纽约市城市地区的橡树（而非红枫树）的生长比农村地区的橡树更容易受到热应激的不利影响，但我们在马里兰州没有看到这些城乡差异。树木提供广泛的重要生态系统服务，增加树冠覆盖率通常是城市可持续发展战略的重要组成部分。根据我们的研究结果，即城市化会影响树木生长对气候变暖的反应，我们建议市政当局在制定植树方案和估计城市森林未来为更广泛的可持续发展目标做出贡献的能力时考虑这些相互作用。