Joseph Bates


Challenge Project

Tree Health in New York City

My research this semester concentrated on the importance of tree health in an urban setting and addressed the problem of poor tree maintenance in populated areas. Ecologists, Urban Planners, and city-goers in general realize that it is difficult to sustain a tree population in large cities. Fortunately movements have begun to spring up in order to increase the number of trees planted per season and to maintain health and longevity. Happy trees, healthy people.

But why are trees so important, especially in cities? Each year trees are able to pull massive amounts of pollution from the air. They recycle Carbon Dioxide and produce Oxygen. These measures are substantially more important in heavily populated urban areas. For this reason I have chosen to focus on the New York City area, the highest concentration of population in the United States.

Through my research I hoped to find a multitude of things. First, I searched for any areas in the New York City area with notably high tree mortality. From there I planned on examining what factors would cause mortality. However, the main question I needed to address was "How can we increase the population of trees in NYC?"

The data-set I used included spatial information, diameter, health and species of the sampled trees. The health status, or "tree-condition" was rated on a 1 to 7 continuum, 1 being the healthiest and 7 being dead or nearly dead. In search of anomalies I singled out the extremes of 1 and 7 and created two seperate dot maps as references.

What does this data indicate? First off it is important not to mistake redundancy for correlation. If we were to overlay these maps they would be very similar. However this does not mean the maps are useless. We see where trees are, and where they are not. There is also evidence of some clumps of high mortality worth noting. Most importantly the maps indicate that there are more healthy trees than there are dead and dying trees. The data conveys that the over-all efforts in progress are working. The question now becomes "How can we do it better?"

Through remote sensing data provided by the Department of Parks and Recreation in NYC I was able to use ENVI to seperate bands of land coverage. Using the REM tool I checked brightness values and compared them to standardized reflectance curves ( to gather information on surface material. The seven seperated bands were Canopy, Grass, Bare Earth, Water, Buildings, Roads, and Paved Surfaces. Of these bands only two were logical candidates; Grass and Bare Earth.

From here I loaded the two bands into ArcMap to display the areas that may be available for planting. What we are left with is the maximum land area that could be available for planting trees. Of course there are other variables to consider such as residential areas and unhealthy land. Nonetheless we have a template for areas to continue the growth of tree population in the New York City area. Let's get planting!