The ecological benefits provided by trees include improving air quality (Nowak, et. al., 2006), mitigating climate change by sequestering carbon (Nowak, 1993), providing animal habitats (Livingston, et. al., 2003), and reducing heat (Edmonson, 2016), among others. Trees also provide numerous social benefits, impacting urban sustainability in particular by improving human health (Salmond, 2016), aesthetically and economically improving neighborhoods (Torres, 2012), and contributing to thriving communities by creating gathering spaces and even reducing crime (Abraham, et. al., 2010). Because of the tremendous potential of trees to provide social and ecological services, particularly in urban areas, tree planting has become an important facet of many sustainability initiatives. This thesis assesses one such initiative aimed at planting trees for the diverse benefits they provide. Valley Permaculture Alliance (VPA), a nonprofit based in Phoenix, Arizona, is known for its Shade Tree Program. The author conducted an internal, quantitative assessment of the program between August and December of 2015. The assessment included evaluation of several indicators of ecological and community health related to the presence of shade trees, culminating in a report released in 2016. This paper evaluates the use of sustainability indicators in the VPA assessment as well as their value in different types of organizations. It culminates with an assessment of VPA's strengths, challenges faced by the organization, and suggestions for its future development.