Patterns of Tree Species Abundance and Diversity on Urban Sidewalks in Macapá, Amapá, Brazil

ABSTRACT Urban afforestation in tropical regions provides key ecosystem services that enhance urban resilience, support biodiversity conservation, and promote human well‐being. This study assessed patterns of species abundance and diversity of street trees based on origin, fruit‐bearing status, and tree size classes in Macapá, Northeastern Brazilian Amazon. Street trees were systematically inventoried along urban blocks across all administrative zones of the city. We recorded 52 species, most of them exotic (75%) and fruit‐bearing (52%), reflecting colonial legacies and local preferences for utilitarian species, especially those used for food production. Notably, none of the native species identified were endemic to the Amazon biome, indicating predominance of widely distributed taxa even among natives used in urban landscaping. Species richness was similar between small (41 species) and medium‐sized trees (41), but declined markedly among large trees (24). This is the first study in the region to apply a systematic field inventory of street trees, revealing a concerning trend: mature, tall species are being replaced by smaller, fast‐growing ones. This shift suggests a reduction or potential loss of important ecosystem services typically associated with large‐canopy trees, such as shade provision, carbon storage, and habitat availability for urban fauna. We also found low average tree density (9.78 ± 2.16 individuals km −1 ; mean ± standard deviation), emphasizing the need for afforestation planning that prioritizes biodiversity, ecological functionality, and climate resilience. Our findings underscore the importance of management strategies that consider species composition, functional traits, and spatial distribution to effectively meet socioenvironmental demands in tropical urban settings.