Urban trees and the services they provide (e.g., evapotranspirational cooling,
shading, recreation, carbon storage, air pollution filtering) can have major effects on the
microclimate of a city, although the growth conditions are often inadequate to ensure tree vitality
and growth, negatively affecting their beneficial effects. In a worldwide dendrochronological
study on ten urban tree species in four climatic zones, the growth and impacts of common urban
tree species were assessed. This paper focuses on the results for Robinia pseudoacacia L. in the
Mediterranean climate city of Santiago de Chile, highlighting the faster growth of the studied
black locust trees since 1960 than its growth in the years before 1960. Furthermore, black
locust displayed the best growth when situated closer to the city center than the city periphery
and when in the northern and western parts of Santiago de Chile. The species characteristics of
black locust also revealed an immediate negative growth reaction to drought events, followed
by a rapid recovery, which was similarly influenced by the direction from and distance to the
city center of the growing site. The results underline the overall worldwide findings on urban
tree growth that indicate that a city climate with an extended growing season and increased
temperatures can lead to improved growth of urban trees in the Mediterranean climatic zone.
However, with increased growth, more rapid ageing and tree death might follow, leading to
increased costs for new plantings and tree management.
