The legacy of neighborhood age: how the past shapes the current diversity, composition, and cover of urban trees

Abstract

The temporal dynamics of urban tree cover remain a knowledge gap in urban ecology, particularly in Latin American cities. This is largely due to the lack of historical data or periodic censuses necessary to assess the ?legacy effect? of past preferences and decisions on the current characteristics of urban trees. In this study, we employed a synchronic approach based on a single census to infer changes in urban trees over time, using neighborhood age as a temporal proxy. We analyzed the effect of neighborhood age on the diversity, composition and cover of urban trees in Yerba Buena (Tucumán, Argentina). We used a database of urban trees in public areas, surveyed in 2022?2023 by the local government, and a map of the city?s tree cover. We used the Google Earth Engine platform to classify neighborhoods by age using maps, aerial photographs, and satellite images. In public areas, Yerba Buena had 29,210 trees from 177 species, with a predominance of non-native species (81%). In neighborhoods urbanized within the last decade, the proportion of planted native species was higher, though non-native species still prevailed. Older neighborhoods had higher tree diversity, species richness, tree cover, and a greater proportion of old and decrepit trees compared to newer neighborhoods. The composition of old or decrepit trees differed from that of newly planted trees. Past decisions and practices have shaped the current characteristics of urban trees in Yerba Buena, which should be considered in their management and planning.