This document discusses updating an urban tree inventory for a city. It provides details on why regular updates are important, how to approach an update, and examples of results from previous inventory updates. Key reasons to update include increased public safety, efficiency, and justifying budgets. Important factors for the update include whether it is a new inventory or updating an existing one. Results shown include changes in tree numbers, diameters, and species composition from inventory updates in two cities over time periods of 7-13 years. Regular updates allow tracking of tree performance and growth.