Using Big Data to help make Policy Decisions for New York City

The Department of Parks & Recreation is responsible for maintaining NYC’s 650,000 street trees and planting 20,000 annually. In order to improve the planning and management of New York City’s street trees, the Department of Parks and Recreation (DPR) commissioned the Young Street Tree Mortality Study, surveying approximately 47,000 trees over 3 phases of data collection. Building on the previous capstone’s findings, the spring 2015 Capstone team aimed to answer five questions posed by DPR relating to: 1) identifying trends and relationships regarding the survivorship of street trees, and 2) identifying factors in survivorship that DPR can act on to improve the longevity of street trees.

The team categorized these questions into two broad policy themes. First, because resources are limited, planting efficiency – where to plant which species of tree – is crucial to DPR. Second, to maximize longevity after planting, the team looked at how trees can be cared for after planting. Although the team could not make causal conclusions, its data analysis of 47,000 street trees is the first of its kind, and its findings are at the forefront of the field of urban forestry.

The  final  report  presented  the  methodology  and  results  of  the  team’s  in-depth statistical and cartographical analysis. It then puts forward recommendations for DPR, both to support urban forestry policy, as well as future data collection and research. The team’s efforts will support DPR as the Young Street Tree Mortality Study continues. As many cities around the world look to New York City as an exemplar of successful urban forestry policy, the impact of this work may extend far beyond city limits.