Present and future ecosystem services of trees in the Bronx, NY

Trees provide ecosystem services such as air pollutant removal, carbon storage and sequestration, urban heat island reduction, stormwater runoff reduction as well as other socio-economic benefits. Large-scale tree plantings are occurring in many cities to increase tree canopy coverage as well as the health, economic and environmental benefits that come with trees. Thus, there is a need to assess the extent to which trees provide these ecosystem services, where services are realized, and most importantly to improve methods of determining future planting locations. Using a new spatially distributed implementation of the i-Tree suite of ecosystem service models and mapping tools, we estimate the current and future ecosystem services and benefits of a recent tree planting initiative within each census block group of the Bronx, NY for 2010 and for three 2030 tree cover scenarios (assuming no tree mortality, 4% and 8% annual mortality). Land cover and tree canopy estimates for 2010 are derived from a high-resolution land cover dataset. A grow-out scenario based on urban tree database information and allometric equations is used to predict future canopy cover. Change analysis is carried out at the census block group level to determine the magnitude and direction of change for each service and benefit over time. The monetary value of trees in the Bronx in 2010 is estimated to be $37.6 million, and this value is estimated to range from $40.7 million to $43.9 million in 2030 if the current canopy is maintained and newly planted trees grow to maturity.