USDA Forest Service

Pacific Southwest Research Station
Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Urban Ecosystems and Social Dynamics

Urban Ecosystems and Processes


What is STRATUM?

STRATUM is a new street tree management and analysis tool for urban forest managers that uses tree inventory data to quantify the dollar value of annual environmental and aesthetic benefits: energy conservation, air quality improvement, CO2 reduction, stormwater control, and property value increase. It's an easy to use, computer-based program. It allows any community to conduct a street tree inventory. The baseline data provided can be used to effectively manage the resource, develop policy and set priorities. Using a sample or an existing inventory of street trees, this software allows managers to evaluate current benefits, costs, and management needs.

Who should use STRATUM?

STRATUM was developed for urban foresters, arborists, non-profit tree organizations, landscape architects and contractors, planners, environmental consultants, and anyone else with a vested interest in their community's urban forest.

What does STRATUM do?

STRATUM uses tree growth and benefit models for predominant urban tree species in 17 national climate zones. Users import data collected in a sample or complete inventory and input community specific information (e.g., program management costs, city population, and price of residential electricity) to customize the benefit-cost data.

STRATUM uses this information to calculate:

  1. the resource's structure (species composition, extent and diversity)
  2. function (the environmental & aesthetic benefits trees afford the community)
  3. value (the annual monetary value of the benefits provided and costs accrued)
  4. resource management needs (evaluations of diversity, canopy cover, and pruning needs).

Reports consist of graphs, charts, and tables that managers can use to legitimize funding, create program enthusiasm and investment, and promote sound decision making. With STRATUM, users can answer the most important question related to their tree program: Do the accrued benefits of street trees outweigh their management costs? In addition, STRATUM will aid managers in improving the return on their investment dollar. For example, STRATUM will help mangers determine what kind of trees should be planted to maximize canopy cover and benefits that are important to their community.

How does STRATUM work?

STRATUM uses growth curves modeled for significant urban tree species within each of 17 national climate zones, along with other regionally specific data: regional climate data, building construction and energy use patterns, fuel mix for energy production, and air pollutant concentrations. This information is used to model the environmental benefits and costs as well as effects on property value.

Map of a city with tree locations marked.After the user imports their sample or full inventory, STRATUM calculates the structure of the resource, net annual benefits and costs, and indicators of management sustainability. Reports compare canopy cover for different neighborhoods, species diversity, conflicts with powerlines and sidewalks, and species performance. Users can choose charts and histograms that display results at the city or neighborhood level, by tree type or species.

Caption for picture: The benefits trees provide are dependent on their location, as well as species, size, and health.

Graph showing the effect of different types of trees on average annual benefit in dollars.What if our city doesn't have an inventory?
STRATUM was designed to incorporate an existing street tree data base where DBH (diameter at breast height) measurements are present for each tree. However, for communities without inventories, a methodology for conducting a sample inventory is presented. The method was designed to be efficient, with a minimal input of time and investment. Using a team of two paid personnel or volunteers, experience has demonstrated that this technique can be completed from start to finish within four to six weeks.

Cities that choose to employ this rapid sampling method will possess all the data needed to utilize the full capabilities of STRATUM.

Caption for graph: Stratum allows users to perform economic evaluations of tree performance.

What makes STRATUM different?

STRATUM differs from other urban forest analysis software in many ways:

  1. STRATUM is designed for analyzing street tree populations, not the entire urban forest
  2. as such, it is intended to be utilized as a management tool, going beyond the display of benefits accrued
  3. costs of management rather than benefits alone are incorporated to provide a platform for strategic planting
  4. STRATUM is not GIS-based, requiring only basic inventory data
  5. state of the art research provides a scientific underpinning for STRATUM's economic reports the benefits and environmental costs of maintaining street trees comes from exhaustive field research and laboratory modeling for each of the 17 climate zones.

Simply, STRATUM functions as a resource management tool to assist managers develop policy, set priorities, and make decisions.

How can I get STRATUM software?
STRATUM software is currently being produced as a stand-alone application with a targeted release date of Spring 2005. Continue to visit our website for updates.

For more detailed information on the possibilities of STRATUM see: A Practical Approach to Assessing Structure, Function, and Value of Street Tree Populations in Small Communities. (.pdf)

STRATUM's future

Through Cooperative Research and Development Agreements, STRATUM is being applied in the development of urban forestry plans in North Vancouver, B.C. and the UC Davis campus. It is also part of a national initiative to integrate three Forest Service software applications (STRATUM, UFORE, and MCTI) into one user-friendly package. The integrated software suite is expected to be available in late 2005.

See STRATUM in action:

How one city has applied the model.

Last Modified: May 16, 2011 07:58:43 PM