PT - JOURNAL ARTICLE AU - Crystal A. Crown AU - Benjamin Z. Greer AU - Danielle M. Gift AU - Fiona S. Watt TI - Every Tree Counts: Reflections on NYC’s Third Volunteer Street Tree Inventory AID - 10.48044/jauf.2018.005 DP - 2018 Mar 01 TA - Arboriculture & Urban Forestry (AUF) PG - 49--58 VI - 44 IP - 2 4099 - http://auf.isa-arbor.com/content/44/2/49.short 4100 - http://auf.isa-arbor.com/content/44/2/49.full AB - TreesCount! 2015 (TC2015) was the third citizen-participatory inventory of street trees in New York City, New York, U.S. Every ten years, the New York City Department of Parks & Recreation has worked with citizen scientists to record the location, size, species, and condition of all public curbside trees. Volunteer street tree inventories promote awareness of the importance of the urban forest and support municipal urban forest management. New York City’s prior street tree inventories in 1995 and 2005 led to advances in customer service, funding for routine street tree pruning, and urban greening initiatives. TC2015 attracted 2,241 voluntary participants through multiple recruitment efforts, more than doubling involvement from 2005. Fully digital data collection improved data quality and facilitated near-real-time quality assurance of data, and advanced tree location methods increased spatial data accuracy from past inventories. Data-collection events and reward strategies were also implemented to promote volunteer engagement. Citizen scientists collected tree location data with a high-level of accuracy (96.1%) after minimal training. All 666,134 street trees surveyed in TC2015 populated NYC Parks’s operational forestry database, as well as a public facing map (NYC Street Tree Map) for tree stewards. The following paper describes TC2015 project design and execution, outlines some of the key changes made since the first inventory in 1995, and provides results-based recommendations for practitioners planning similar projects.