Chapter three describes the heart of the MillionTreesNYC campaign: planting one million trees. It focuses on the organizational, governance, and material arrangements involved in transforming the city’s urban forest. A formal public-private partnership was created to run the campaign, an example of truly hybrid governance at work. The prominence and scale of the initiative led to major organizational changes in the two core partners. They both garnered and expended massive amounts of financial and human resources in the planting of a million trees. Counting the number of trees planted was central to the public identity and internal functioning of the campaign. The conduct of urban forestry in New York City was radically altered by the MillionTreesNYC campaign. New guidelines, routines, and procedures were developed to alter the practice of urban forestry on streets, in parks, in “natural areas,” on public housing grounds, and on private land.