A natural experiment occurred when the Emerald Ash Borer caused extensive and nearly instantaneous loss of street trees throughout Ann Arbor, Michigan over the past several years.  Where ash trees are clustered, the ecological and aesthetic integrity of neighborhoods has dramatically changed in a single season along with the restorative benefits provided by these trees.  I will describe a two-tiered experiment, currently underway, which takes advantage of this disturbance to a managed urban ecosystem.  It begins with an evaluation of the impact of street tree loss on indices of ecosystem health, human health and perceived aesthetic value.  This will be followed by a discussion of design options and management strategies ranging along a stewardship continuum in the context of their impact on ecosystem health, human health and perceived aesthetic value.