Cities present warmer environmental conditions than the surrounding areas due to the high concentration of CO2 in the atmosphere, abundance of concrete surfaces, and changes in precipitation patterns. Identifying the vulnerability of urban tree species to high temperatures is an essential goal in response to our changing climate. One major stressor in cities is the thermal pollution associated with the urban heat island (UHI) effect. However, direct evidence supporting physiological adaptation to urban environments in trees is remarkably limited. That's why we want to go beyond and identify what extent stress factors (i.e. temperature) alter the development of organisms, taking the cities as an experimental design to test the effects of climate change. For this study, we will compare the thermal tolerances of tropical and temperate tree species in urban environments and compare them with their synonymous counterparts in natural forest using the warming tolerance method.