developing an i-Tree Community model
This website could be the first product in a three phase effort:
1. Introduction to i-Tree
i-Tree is a suite of analysis software tools provided by the USDA Forest Service for urban stakeholders. Modules are in the public domain and are available on-line at no charge. The analytic tools quantify the structure of community forests and the benefits that urban trees provide, including economic valuation. Analysis topics largely address environmental services (such as air and water quality, and energy savings), and include market valuation of properties. The i-Tree tools help communities of all sizes to strengthen their urban forest planning and management efforts. Since release of the i-Tree tools in 2006, numerous communities, non-profit organizations, consultants, volunteers and students have used i-Tree to report on the status of individual trees, parcels, neighborhoods, cities, and even entire states.
2. i-Tree Community :: A New Analysis Module
The current i-Tree modules provide ecosystem services analysis based on city tree and canopy data inputs. The analysis algorithms largely focus on biophysical benefits and functions. The only representation of socio-cultural ecosystem services is hedonic and market analysis of residential properties. Yet about 40 years of social science research points to an extensive array of human health and well-being (HHWB) benefits that are provided by the human experience of nature within built environments. These benefits accrue at all social scales: individual, household, neighborhood, community, and city-wide. Another analysis module can be developed to communicate HHWB benefits, providing another set of tools to demonstrate why urban greening is an integral element of urban systems. This knowledge may appeal to stakeholder groups that have not traditionally been included as partners in green infrastructure efforts (such as public health, human services, therapy and healing facilities).
3. i-Tree Community :: Research and Development
Research and development of an i-Tree Community module would involve these three steps:
a. Science Assessment and Summary
The first step is to assess and compile scientific studies on urban nature experience and HHWB. This literature is extensive but is located in publications across many disciplines (including psychology, sociology, geography, urban planning, and urban forestry) so is not readily available to professionals and managers. This process is underway; a bibliographic review of HHWB benefits is being prepared at the University of Washington (Project Director, Dr. Kathleen Wolf) to be completed by December 2010. The resulting summaries (sorted by themes on this web site) will be the fundamental scientific building blocks for a sociocultural i-Tree module.
b. Geospatial Modeling
Once the full range and scope of human well-being benefits are understood, the next step is a map-based benefits analysis. Canopy cover mapping has already been done in many cities. Meanwhile, many sociocultural functions are land-use based as there are distinct benefits associated with different land use types - such as residential, retail, commercial, and public institutions (for example schools). Mapping social benefits by land use and in relationship to canopy cover and other urban greening indicators, would demonstrate the importance of urban forest planning and management for human functioning and health. Positive correlations and relationships are highly likely between the presence of trees (now readily mapped) and psychosocial outcomes. Examples include physical activity, respiratory disease, and crime rates.
c. Economic Valuation
Economic valuation of benefits is a product of i-Tree analysis that can generate community interest, then action to support tree retention and planting. Once the full range and scope of human well being benefits are understood and mapped, it is possible to express those benefits in economic terms.
Well-being benefits are intangible, non-market “products” that green infrastructure provides. Economists have developed numerous strategies for non-market valuation of urban natural resources. For instance, non-market valuation approaches have been used to calculate the value of city trees’ contribution to urban air and water quality effects.
Similar approaches could be applied to psychological and social outcomes across human populations, and across different built environments in cities and towns (Figure 1). For example, the public health benefits and costs of neighborhoods made more walkable by the presence of trees could be economically valued. The availability of such valuations would be a powerful tool in creating and shaping urban greening policies.