Urban trees are increasingly being used to help cities adapt to climate change, improve health and wellbeing, and promote biodiversity. Yet these benefits are distributed unequally, mirroring the uneven distribution of the urban forest in many cities. Contrasting theories have been proposed to explain these observed patterns that focus either on the economic wherewithal of individuals (the ‘luxury effect’), or the outcome of structural factors such as municipal decision-making processes. Here, we explore patterns across 10 municipal authorities in greater Melbourne, Australia to compare the relative importance of these competing mechanisms. We show that both individual and structural processes are both major determinants of the density and diversity of trees in this large Australian city. Interestingly, education level was strongly related to tree density, while household income was negatively related to tree density and diversity in some municipalities. The luxury effect was not able to adequately explain the patterns observed in Melbourne. This finding has important implications for the planning and management of urban forests and the equitable distribution of the benefits they provide, in the context of the rapid expansion of urban populations across the globe. To counteract inequity, local municipalities must acknowledge and deliberately overcome internal biases that favour the provision of street trees to more advantaged sections of the community.

城市树木越来越多地被用于帮助城市适应气候变化、改善健康和福祉以及促进生物多样性。然而，这些收益分配不均，反映了许多城市的城市森林分布不均。已经提出了对比理论来解释这些观察到的模式，这些模式要么关注个人的经济资源（“奢侈品效应”），要么关注结构性因素（如市政决策过程）的结果。在这里，我们探索了澳大利亚大墨尔本地区 10 个市政当局的模式，以比较这些竞争机制的相对重要性。我们表明，个体和结构过程都是这个澳大利亚大城市树木密度和多样性的主要决定因素。有趣的是，在一些城市，教育水平与树木密度密切相关，而家庭收入与树木密度和多样性呈负相关。奢侈品效应无法充分解释在墨尔本观察到的模式。在全球城市人口快速扩张的背景下，这一发现对城市森林的规划和管理以及它们所提供的利益的公平分配具有重要意义。为了消除不平等，地方市政当局必须承认并有意识地克服内部偏见，这些偏见有利于向社区中更有优势的部分提供行道树。在全球城市人口快速扩张的背景下，这一发现对城市森林的规划和管理以及它们所提供的利益的公平分配具有重要意义。为了消除不平等，地方市政当局必须承认并有意识地克服内部偏见，这些偏见有利于向社区中更有优势的部分提供行道树。在全球城市人口快速扩张的背景下，这一发现对城市森林的规划和管理以及它们所提供的利益的公平分配具有重要意义。为了消除不平等，地方市政当局必须承认并有意识地克服内部偏见，这些偏见有利于向社区中更有优势的部分提供行道树。