:: The Project ::

Over the past several decades, city trees (collectively termed the urban forest) have been shown to provide numerous environmental quality benefits, such as runoff sequestration and air purification. Recent studies have even begun to put a dollar value to these important environmental services. Many city agencies, NGOs , and communities are now interested in mapping their local and regional forests and estimating their environmental impact and economic value. Several computer applications have recently been developed to help groups accomplish this.

This web-based project investigates two computer-based applications that are used to analyze urban forest structure, quantify its environmental impact and economic value, and inform management and planning decisions. The first piece of software is free to the public and is called the ‘Urban Forest Effects Model’ (or UFORE). Developed by the U.S. Forest Service, UFORE operates in the statistical package SAS and is often used in tandem with GIS applications. It relies on field data collected from random points in a city to return information related to urban forest structure, carbon storage and sequestration, building energy use, pollen production and impact, and air pollution.

The other piece of software is the GIS based CITYgreen application, developed by American Forests. It is used to analyze the impact of urban greenspace structure on runoff, air pollution, carbon sequestration, energy, and creates maps and projections based on this data.

On these pages I examine the following questions: How and why were the models developed? What assumptions do they rely on to provide environmental quantifications (such as “lbs of CO2 sequestered” or “Gallons of runoff sequestered”) and convert these services to dollar values? How do they differ from one another— either by accessibility and use, assumptions, and/or scope. What critiques have been made of their function and use? By whom are they used and to what end?