Pacific Southwest Research Station

Pacific Southwest Research Station
800 Buchanan Street
West Annex Building
Albany, CA 94710-0011

(510) 559-6300

Urban Ecosystems and Social Dynamics Program

Urban Ecosystems and Processes

What's New

New Tool: Updated, online Tree Carbon Calculator (beta)

A beta release of the public version of the Tree Carbon Calculator, a computer tool to help the public estimate carbon and energy impacts of trees on a single family residential property is available through the ecoSmart Landscapes Portal at www.ecoSmartLandscapes.org. Use Google Chrome, Firefox or IE9 to access. The Carbon and Energy tool is the first in a new suite of tools allowing users to take an integrated approach to planning landscaping at the residential and community level. This release includes all California climate zones. Expect a release for the remainder of the U.S. in 2013. Learn More

Interception and Bioswales

Although urban foresters have embraced tree planting as a stormwater management strategy, relatively little science has quantified its effectiveness. Drs. Qingfu Xiao (UC Davis) and Greg McPherson’s paper “Rainfall interception of three trees in Oakland, California” compared the amount of rainfall intercepted by three tree species, and concentrations of nutrients and metals from samples collected under the trees. In “Performance of engineered soil and trees in a parking lot bioswale”, Drs. Xiao and McPherson compared runoff and pollutant loading from eight parking spaces adjacent to a control and the bioswale treatment in Davis, CA. The bioswale reduced runoff by 89% and total pollutant loading by 95%. In November, McPherson and Peter McDonaugh, a landscape architect, presented “Large Trees for Stormwater Management: Fact or Fiction” to 200 engineers and architects attending the Greenbuild International Conference & Expo at the Moscone Center in San Francisco. For more information please contact Dr. Greg McPherson (gmcpherson@fs.fed.us; 530-759-1723).

Municipal Forest Health Threat Assessment

The "California Municipal Forest Health Threat Assessment" reports the extent to which California's municipal forests are at risk from insect pests and plant disease threats. The assessment integrated two existing software applications and data from 30 California street and park tree inventories. The two tools used in the analysis were the Pest Vulnerability Matrix and i-Tree Streets. Prioritized recommendations are helping communities to increase the resilience of their municipal forests through improved tree selection, monitoring, integrated pest management, and removal and replacement planning. For a copy of the report, contact gmcpherson@fs.fed.us.

Science in Practice

Standardized Tree Monitoring Protocols

At the recent ISA Annual Meeting in Portland, Oregon, the Urban Tree Growth & Longevity Working Group (UTGL) organized a special symposium on tree monitoring. Dr. Greg McPherson (USDA Forest Service) opened the symposium and moderated a panel discussion. Dr. Lara Roman (UC Berkeley) presented results from a questionnaire on tree monitoring practices of 32 local organizations across the United States. Based on participant feedback, the UTGL will begin drafting Urban Tree Monitoring Protocols. View the Project Prospectus. If you are interested in helping to develop and review the protocols, contact Lara Roman (lararoman@berkeley.edu).

Carbon Offsets and Urban Forests

California is at the forefront of efforts in the U.S. to develop policies that address climate change, including the first set of protocols that allow urban forestry projects to participate in the state’s cap-and-trade program. Dr. Greg McPherson and co-sponsors organized the Carbon Offsets & Urban Forests Workshop to explore and advance opportunities for urban forest projects. Emerging from that workshop was a Carbon Offsets & Urban Forests Team that has met monthly to 1) revise the protocol to increase participation; 2) develop a new protocol for tree planting and conservation to mitigate greenhouse gas emissions from land development projects; and 3) create a web-based Community of Practice to promote shared learning and advance pilot projects. For updates contact Dr. Greg McPherson (gmcpherson@fs.fed.us).

Urban Tree Canopy (UTC) Assessments

A new generation of remote sensing and GIS technologies have spurred UTC assessments for urban forest planning and management. These top-down assessments are used to quantify the extent and value of services provided by the existing urban forest, as well as the potential to expand UTC and increase benefits. Dr. Greg McPherson moderated a panel of experts who gave a “Comprehensive Update on Tree Canopy Assessments” at the Arbor Day Foundation’s National Partners in Community Forestry Conference in Sacramento (November, 2012). Over 80 attendees expressed interest in participating in a shared learning network to advance understanding and improve access to information, expertise and technologies.

Growing and Governing Green Infrastructure

Urban green infrastructure, including urban forests, is an important strategy for providing public goods and increasing resiliency while reducing ecological footprints and social inequity in metropolitan areas. In a recent paper, Drs. Robert Young and Greg McPherson found that visioning, planning and management of six large-scale tree planting initiatives was largely dominated by the public sector, unlike more transdisciplinary strategies in environmental governance. Many of these initiatives have had little success becoming institutionalized. In a previous paper, they described strategies for sustaining such initiatives. Also, Dr. Young described the role of planning in advancing these initiatives, and identified best practices that can inform future efforts to expand tree planting on a metropolitan scale.

Recent Publications

The Urban Tree Growth & Longevity Conference at the Morton Arboretum resulted in two products - the Conference Proceedings and a recent special issue of Arboriculture & Urban Forestry containing a series of papers presented at the conference. Urban Tree Growth & Longevity: Introduction provides an overview of topics covered in the special issue while Greg McPherson and Paula Peper’s paper, Urban Tree Growth Modeling, describes long-term growth studies, various modeling approaches and the development of a national tree growth database with over 1,800 growth equations from measurements of over 17,000 trees in 16 U.S. cities.

What is the value of a tree? What environmental services do they provide and at what cost? Our new Trees Pay Us Back brochures answer these and other questions. Produced in partnership with CAL FIRE Urban and Community Forestry, these brochures present information on trees in the 16 U.S. climate zones where research was conducted for our Community Tree Guide series and i-Tree Streets. From the Southern and Northern California Coast to the Northeast, Coastal Plain, and Central Florida regions, click to view and download the PDF for your region.

The State of California's urban forests: integrated approaches offer the best solutions. Urban forests face mounting challenges. Greg McPherson, Andy Lipkis, John Melvin and Matt Ritter discuss the problems and solutions.

Greenhouse Gas Inventory of an Ornamental Tree Production System. This article reports the results of a study to determine the greenhouse gas (GHG) emissions from nursery production of ornamental trees for urban forestry.

Comparison of Methods for Estimating Carbon Dioxide Storage by Sacramento's Urban Forest. This chapter by Drs. Elena Aguaron and Greg McPherson in Carbon Sequestration in Urban Ecosystems determines and examines variability among CO₂ estimation approaches.