Already growing in a harsh environment, street trees face ongoing stresses that affect their health and longevity. If climate changes, what will be the impact on these trees? Is there a method one can use to predict or determine how to manage the urban forest under a changing climate? Will climate change have a positive or negative effect on street trees? The City of Victoria, BC, Canada is known as the Garden City. It has a mild temperate climate and an established urban forest. Effects of changing climate are now visible on specific tree species. A key factor for street tree health and longevity is determining available moisture during dry spells. Computer generated climate models for 2020, 2050 and 2080 indicated that available moisture for the Victoria area will decline during hotter summer months. Using the techniques established in this book arborists can generate future climate models for their area that predict how changes in temperature and moisture will affect the urban forest. From these predictions it may then be possible to plan and maintain the urban forest under changing climate conditions.