Sierra Nevada Research Institute, University of California, Merced, Merced, CA, 95340, USA; Graduate Program in Environmental Science, State University of New York College of Environmental Science and Forestry, Syracuse, NY, 13210, USA.
State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, Fujian Normal University, Fuzhou, 350007, PR China; School of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, PR China.
J Environ Manage. 2021 May 1;285:112207. doi: 10.1016/j.jenvman.2021.112207. Epub 2021 Feb 23.
Most street tree inequality studies focus on examining tree abundance at single time point, while overlooking inequality dynamics measured based on a complete set of tree measures. Whether the severities of street tree inequalities vary with different tree structure measures, whether street tree inequalities are diminishing or growing over time, and how the inequality dynamics are affected by tree-planting programs remain largely unexplored. To fill these gaps, this study applied binned regression and cluster analyses to street tree census data of 1995-2015 in New York City. We investigated different structural measures of street tree inequalities pertaining to various aggregations of people, compared street tree inequalities over time, and revealed the inequity remediation role of the MillionTreesNYC initiative. We found that the underprivileged populations, characterized by higher percentages of the poor, racial minorities, young people, and less-educated people, are more likely to have lower tree abundance, less desired tree structure, poorer tree health condition, and more sidewalk damages. When disaggregating inequalities across various aggregations of people, income-based and education-based inequalities were the most severe, but the inequalities diminished over time. The race-based and age-based inequalities show mixed results that disfavor Hispanics, Blacks, and young people. The equity outcome of the MillionTreesNYC initiative is not ideal as the inequalities decrease when measured using tree count and species diversity, whereas they increase when measured using tree health and average diameter at breast height. The findings have important implications for more effective decision-making to balance resources between planting trees and protecting existing trees, and between increasing tree abundance and improving tree structure.
大多数街道树木不平等研究都集中在单一时间点检查树木的丰度，而忽略了基于一套完整树木指标衡量的不平等动态变化。街道树木不平等的严重程度是否会随着不同的树木结构指标而变化，街道树木不平等是否随着时间的推移而减少或增加，以及树木种植计划如何影响不平等动态变化，这些问题在很大程度上仍未得到探索。为了填补这些空白，本研究应用分箱回归和聚类分析方法，对纽约市 1995-2015 年的街道树木普查数据进行了分析。我们研究了与不同人群聚集相关的街道树木不平等的不同结构指标，比较了随时间变化的街道树木不平等，并揭示了 MillionTreesNYC 计划在纠正不平等方面的作用。我们发现，弱势群体（其特征是贫困人口、少数族裔、年轻人和受教育程度较低的人口比例较高）拥有较低的树木丰度、较差的树木结构、较差的树木健康状况和更多的人行道损坏。在将不平等情况按不同人群进行细分时，基于收入和教育的不平等最为严重，但不平等程度随时间的推移而减少。基于种族和年龄的不平等存在混合结果，对西班牙裔、黑人和年轻人不利。 MillionTreesNYC 计划的公平结果并不理想，因为当用树木数量和物种多样性来衡量时，不平等程度会降低，而当用树木健康和平均胸径来衡量时，不平等程度会增加。这些发现对于更有效地做出决策具有重要意义，以在种植树木和保护现有树木之间、在增加树木数量和改善树木结构之间实现资源平衡。
