Biomass is regarded as an important indicator of ecological and management processes in urban vegetation, difficult to measure but easy to interpret. Existence and growing rates of biomass can be used to calculate carbon storage and sequestration, estimate dry deposition of air pollution or volatile organic compound emissions. In cities, management practices also affect the amount and distribution of biomass components within a tree and local calibrated equations should be used. However, traditional destructive methods to gather the data necessary to build such equations are less practical in urban environments. The main objective of this work was to develop above ground biomass and leaf area models by using non destructive methods for common urban trees in Santiago, Chile. We used randomised branch sampling (RBS), a non-destructive method, and easily measured variables such as DBH and total height to estimate crown biomass and leaf area for the 11 most common urban tree species in Santiago. Results using equations developed in this study yielded crown biomass estimates, comparable and within the range of values reported in literature and within those obtained from urban forest structure models. Leaf area results yielded more reasonable estimates when compared to field data and urban forest structure models. These equations can be incorporated into urban forest function models for more precise estimates of Latin American temperate urban forest function. With increased sampling intensity the RBS sampling method could be presented as a non-destructive and repeatable method for estimating different types of urban tree crown characteristics.