Hazards Planning Center

Hazardous Tree Management and Post-Disaster Recovery

Trees damaged by storm

Damaged trees often block roads and fall on buildings and vehicles, sometimes killing or injuring people unfortunate enough to be in their path.

Debris removal costs hundreds of millions of dollars annually.

PAS Report 555 coverThere are, however, ways to mitigate the damages and costs without simply getting rid of trees, which serve vital ecological, economic, and social functions in the urban environment, a subject documented extensively in APA’s 2009 Planning Advisory Service Report No. 555, Planning the Urban Forest.

The U.S. Forest Service teamed up with APA, with vital in-kind support and participation from the International Society of Arboriculture, to sponsor a two-day scoping session at its office in Washington, D.C., June 16-17, 2014.

Representatives of relevant federal agencies and some other nonprofit organizations were invited, along with several subject matter experts, and the list of those who attended appears below. During the scoping session, the participants discussed problems and potential solutions for better protecting the urban forest during and after disasters.

This page provides a summary of the discussion, the briefing papers presented by the subject matter experts, and a brief annotated bibliography produced by APA for this project.

The APA Hazards Planning Research Center sincerely hopes that what is presented here is not the end, but the beginning, of an ongoing discussion of these issues that may ultimately yield changes in policies and programs that will help achieve the goals of this project.

The center also thanks its intern, Andreas Safakas, for his work in organizing the many elements of the program and coordinating attendance and logistics among the participants listed below.

Scoping Session Summary

The U.S. Forest Service (USFS) and APA have conducted a number of conversations in recent years about the issues connected with storm- and other disaster-caused damage to the urban forest, as well as the need in some communities for significant tree risk management and reforestation after major disasters, such as hurricanes and tornadoes. The goal of this project is to foster improved consideration and protection of community tree infrastructure by lead agencies both before and after disasters. This includes both consideration of the urban forest in planning for hazard mitigation as well as in the response phase and both pre-disaster planning for recovery and post-disaster recovery planning and implementation.

On June 16, attendees heard presentations from subject matter experts on current practices in hazardous tree management, trees and community green infrastructure, prioritizing community tree risk, managing community tree risk, and best practices in community tree risk assessment, as well as technical issues with FEMA-325, Debris Management Guide. On June 17, the discussion focused on policy strategy and next steps.

Through these presentations and subsequent discussion, several major themes emerged. These included the important role that trees and the urban forest play as community green infrastructure; the importance of pre-planning for post-disaster recovery; a need to incorporate current arboricultural best practices into FEMA guidelines; and changes in the vocabulary of risk as it pertains to tree and urban forest management.

1. Trees as Community Green Infrastructure

Trees and the urban forest provide communities with many benefits. They are important natural and cultural resources, which can help foster community identity. Trees are also a form of community green infrastructure, and provide important ecosystem services such as stormwater management, erosion control, and energy conservation. As a result, trees should be considered as infrastructure in recovery (see Trees as Community Green Infrastructure).

A challenge with the urban forest as infrastructure in a disaster event is that it takes years to grow and cultivate, but can be destroyed in a single storm. Tree debris can be one of the most expensive aspects of storm response, and if handled poorly, the community can be faced with years of expensive restoration costs. How is this addressed in planning and recovery?

Inventories and analyses of the urban tree canopy are an important tool for communities in managing the urban forest and improving resilience to disaster. USFS has developed the i-Tree software suite (www.itreetools.org) to provide analysis and benefits assessment of the urban forest. i-Tree Eco can quantify the structure of the urban forest, its environmental effects, and its value to the community using data from either complete samples or random plots and data on meteorological and air pollution data. Using current tree cover and impervious cover data, i-Tree Hydro can quantify and illustrate changes in stream flow and water quality that may result from storm impacts at the watershed and city scales.

Discussion on trees and the urban forest as green infrastructure focused on the need to quantify the benefits. Research has been conducted by both the US Environmental Protection Agency (EPA) and the USACE that quantify the benefits of green infrastructure. Additionally, USFS has worked with the University of Washington and the University of Illinois on a number of conclusive studies quantifying the human health benefits of trees as green infrastructure.

2. Pre-Planning for Post-Disaster Recovery

Disasters can have a devastating effect on urban forests, as can the clean-up activities that immediately follow a disaster. Pre-planning for post-disaster recovery of the urban forest can greatly facilitate recovery. While every disaster event is unique, communities that have pre-planned and that have established contracts and rates in place can facilitate recovery.   Licensed and qualified arborists should be included throughout the pre-planning, disaster response, mitigation, and post-disaster recovery processes.

Depending on the scale of a disaster, the urban forest may not seem like a significant concern during recovery, but recovery costs can be exacerbated by overzealous tree removal during the response phase, as well as by risks associated with remnant trees. Pre-planning can help ensure that these issues are addressed effectively and remain a priority throughout a recovery process. This would include ensuring that qualified arborists are available as needed to assess hazard tree risk and eligibility for FEMA reimbursement.

In addition to pre-planning, utility companies and communities can take a proactive approach to managing tree risk prior to a storm event by preparing Vegetation Risk Management Plans (VRMPs) (see Prioritizing Community Tree Risk — Utility Rights of Way). Employing a VMRP identifies and mitigates risk proactively, which reduces the probability of damage by trees and amount of tree debris resulting from a storm event, in turn reducing emergency management costs. As a result, there is a need to focus urban foresters and arborists on disaster planning to identify and mitigate risk beforehand.

3. FEMA Guidelines

Current FEMA guidelines, as defined in FEMA-325, Debris Management Guide, address trees in the context of vegetative debris eligibility and defining hazards ("It has more than 50 percent of the crown damaged or destroyed; It has a split trunk or broken branches that expose the heartwood; It has fallen or been uprooted within a public-use area; and/or It is leaning at an angle greater than 30 degrees.") FEMA-325 further defines criteria for hazardous limb and tree stump removal.

Currently, the incentive structure of FEMA debris removal programs, which can include paying tree removal contractors by volume, may incentivize removal where it may not be indicated by arboricultural Best Management Practices (BMPs). As FEMA guidelines are revised, there is a need to incorporate arboricultural best practices related to tree risk assessment as further discussed below.

Additionally, FEMA guidelines provide funding for reforestation only through mitigation funding, which is competitively awarded. The discussion focused on the need for trees to be addressed as infrastructure within the FEMA recovery framework, especially if planted as a regulatory response to stormwater management and water quality attainment goals, as this would allow trees to be part of FEMA's regular mitigation program.

4. Risk Management

Responses to tree risk are often reactive in nature — a tree failure happens and the resulting consequences are addressed. As a result, tree risk management is driven more by concern over negative consequences than a true understanding of quantifiable risk (see Managing Community Tree Risk). In order for communities to manage appropriately at both the tree and system levels, there is a need to balance the benefits of trees against the risks, and work on evolving the understanding of tree risk management, which is a culmination of long-term policy decisions.

Increasingly, with the American National Standards Institute (ANSI) A300 Standard (Part 9:2010) and International Society for Arboriculture BMP for Tree Risk Assessment, there has been a standardization of practices for tree risk assessment. These standards, which can be used before or after a disaster, provide guidance to arborists to help them assess and evaluate risk using one of three levels of assessment: limited visual, basic, or advanced. Risk is assessed based on the likelihood of failure, the likelihood of impacting a target, and consequences (see Best Practices in Community Tree Risk Assessment).

By employing a qualified arborist to assess tree risk and eligibility for FEMA reimbursement, communities can mitigate losses before, during, and after storm incidents. Specifically, the knowledge of how a particular tree species responds to damage is critical to making decisions in favor of retention over removal. Years of community investment and accumulated and future ecological, public health, and economic benefit can be lost in a decision to remove a tree. The potential savings is reason to consult with a qualified arborist to prepare a local urban forest management plan for trees that includes an assessment of current conditions, an emergency plan, and specific reference to post-storm assessment.

In areas where qualified arborists are not available in sufficient numbers, the U.S. Forest Service has developed a response and recovery resource for communities. The Urban Forest Strike Team can be requested through local, regional, or state emergency management agencies to deploy qualified arborists to assess hazardous tree risk and FEMA eligibility for removal or pruning.


The presentations and discussion of the scoping session highlighted trees as an important component of community infrastructure; the need for pre-planning for post-disaster recovery of the urban forest; and the importance of incorporating current arboricultural best practices into FEMA guidelines, including the latest standards for risk assessment related to tree and urban forest management. The session also identified several other issues related to hazardous tree management: education, engagement, and prioritization on the local and state levels. Attendees discussed the need for both more education and a broadening of engagement on tree management beyond the urban forestry profession. Because so much of the decision making regarding the urban forest is local, there is a need to recruit local support, both from community members and nonprofit organizations and from local government leadership.

The attendees also discussed the importance of prioritizing the urban forest as a component of community green infrastructure on the local level. In order for the urban forest to be addressed in disaster management and recovery, it needs to be a local priority. Communities also need to bring green infrastructure to the state level as a priority, as states have the primary responsibility for decision making related to hazard mitigation.

In order to continue to advance the management of trees as green infrastructure, it is important that this issue be incorporated into larger conversations taking place on the local, state, and federal levels around hazard mitigation, disaster recovery, and climate action and resilience.

Subject Matter Experts

As part of the preparations for the scoping session, APA worked with the U.S. Forest Service and its partners at the International Society of Arboriculture to identify a handful of subject matter experts who could contribute experience and expertise to help frame the discussion.

Several of these experts were also invited to prepare briefing papers, which are also presented here. In some cases, these experts were unable to attend the scoping session, in which case the paper was presented by one of the U.S. Forest Service representatives.

Rachel BarkerRachel Barker, Project Manager, Project Management Office, ArborMetrics Solutions, Inc.
Rachel Barker is responsible for both expanding business development as well as assisting the ArborMetrics Project Management Office in streamlining and improving project operations. She specializes in coordination and communication of AMS projects to deliver quality services to clients. Barker has more than 20 years of experience in municipal and government operations as well as management having served as a city horticulturist, a city arborist, and in upper management as the deputy director of operations of public services in Columbus, Georgia. She received her bachelor's degree in landscape and ornamental horticulture from Auburn University and her master's degree in public administration from Columbus State University. She is a Project Management Professional (PMP), and an ISA Certified Arborist. Barker is the past president of the Alabama Urban Forestry Association and the current president of the Society of Municipal Arborists.

Eric DavisEric Davis, ISA Certified Arborist, President and Founder, Tree Care, Inc. 
Eric Davis is the owner and president of Tree Care, Inc., which has been based in Dayton, Ohio, since 2000. Davis has been an ISA Certified Arborist since 1998, become a Board Certified Master Arborist in 2010 and currently serves on the board of the Ohio Chapter International Society of Arboriculture. He has been involved in Robert T. Stafford Disaster Relief and Emergency Assistance Act (Stafford Act) funded projects since 1996, working on assignments such as Hurricane Katrina, New Orleans; Hurricane Dolly, Hidalgo County, Texas; and Superstorm Sandy, New Jersey. In addition to his accomplishments in the tree industry, Davis serves on the board of directors for the Overfield School located in Troy, Ohio, and is a commercial pilot. He lives in Troy, Ohio, with his wife, Lori, and their children, Kylie and Wade.

Mark DuntemannMark Duntemann, President, Natural Path Urban Forestry Consultants
Mark Duntemann is the president of Natural Path Urban Forestry Consultants. Based in Oak Park, Illinois, the company serves an international client base. Mark's primary focus is on municipal urban forestry policy development. He has provided expert testimony in more than 50 tree-related injury and fatality cases. This work informs his strategic guidance to agencies to reduce the potential for negative events occurring from trees. Duntemann has a Master of Science in Urban Forestry from the University of Wisconsin – Madison and is past-president of the Illinois Chapter of the International Society of Arboriculture (ISA).  He is an ISA Board-Certified Master Arborist and an ISA Tree Risk Assessment Qualification instructor.

E. Thomas SmileyE. Thomas Smiley, Ph.D., Arboricultural Researcher, Bartlett Tree Research Lab
Tom Smiley is an arboricultural researcher at the Bartlett Tree Research Laboratory in Charlotte, North Carolina, and an adjunct professor of Urban Forestry at Clemson University. Smiley is active in the arboriculture industry and has co-authored the ISA's Best Management Practices for Tree Risk Assessment, Lightning Protection, Fertilization, Support Systems and Construction Management. His research has led to improved methods of increasing sidewalk longevity near trees, protecting more trees from lightning damage, improving tree root growth in compacted soil using the patented Root Invigoration process, and better predicting trees failures.


Kristyn Abhold, Intern, White House Council on Environmental Quality

Mark Buccowich, Assistant Director of Forest Management, USDA Forest Service

Keith Cline, Director, Fairfax County (VA) Urban Forest Management Division

Eric Davis, President and Founder, Tree Care, Inc.

Mark Duntemann, Owner, Natural Path Urban Forestry Consultants

Claire Hadfield, Intern, U.S. Department of the Interior

Dudley Hartel, Center Manager, USDA Forest Service

Debbie Hill, Emergency Management Specialist, U.S. Department of Agriculture, Office of Homeland Security

Chitra Kumar, Deputy Assistant Director for Water, White House Council on Environmental Quality

Edward LeBlanc, Project Engineer, U.S. Army Corps of Engineers

Edward Macie, Regional Coordinator, USDA Forest Service

Caroline Massa, New York Sandy Recovery Office, Natural and Cultural Resources Liaison, Federal Emergency Management Agency

James McGlone, Urban Forest Conservationist, Virginia Department of Forestry

Anna Read, Senior Program Development & Research Associate, APA

Phillip Rodbell, Program Manager, USDA Forest Service

David Rouse, AICP, Director of Research and Advisory Services, APA

James Schwab, AICP, Manager, APA Hazards Planning Research Center

Donald Simko, Emergency Management Program Specialist, Federal Emergency Management Agency

James Skiera, Executive Director, International Society of Arboriculture

Thomas Smiley, Arboricultural Researcher, Bartlett Tree Research Laboratory

Howard Stronach, Regulation and Policy Branch Chief, Federal Emergency Management Agency, Public Assistance Division

Linda Wang, Forest Taxation Specialist, USDA Forest Service, State and Private Forestry

Samantha Wangsgard, Fairfax County (VA) Urban Forest Management Division

M.J. Wilson, New York Sandy Recovery Office, Infrastructure Liaison, Federal Emergency Management Agency

Larry Wiseman, Fellow, Virginia Tech, Center for Leadership in Global Sustainability

Karen Zhang, National Coordinator—Natural and Cultural Resource Recovery, U.S. Department of the Interior

Annotated Bibliography

Prepared by Nick Ammerman, Library and Taxonomy Manager, American Planning Association, May 2014

Abramovitz, Janet N. July 1, 2002. "Are Humans to Blame for Exacerbating Many Natural Disasters?" USA Today.

  • This article suggests that humans are to be blamed for natural disasters. Makes a distinction between natural disasters, which occur within an ecosystem, and unnatural disasters, which are caused by human interference.

American Forest Foundation, My Land Plan. Natural Disasters. Available at http://mylandplan.org/content/natural-disasters

  • Tips on protecting woodlands and forests from various natural disasters. Includes wildfires, drought, hurricanes, tornadoes, floods, ice storms, and windstorms. Each section also includes links to resource guides.

Bradshaw, Corey J. A., Navjot S. Sodhi, Kelvin S.-H. Peh, and Barry W. Brook. 2007. "Global Evidence That Deforestation Amplifies Flood Risk and Severity in the Developing World." Global Change Biology. 13.11: 2379-395.

  • Claims to be the first empirical study to prove that deforestation leads to greater floods. It takes on a global scale analysis, and compares a variety of variables. Overall, it presents strong empirical data suggesting that deforestation leads to greater floods due to a loss of vegetation that retains soil.

Breithaupt, Stephen, and Tarang Khangaonkar. 2011. "Effects of Wetland Restoration on Floodplain Hydrodynamics under Extreme Flooding Conditions." Ecological Restoration. 2.9: 161-72.

  • This case study analyzes a restoration project in Washington. While the restoration project did not have an impact on water levels, it did seem to benefit the natural environment more than dikes and other human-made flood prevention.

Central Alabama Regional Planning and Development Commission. January 2012. "Vegetation Risk Management Plan Template." Available at www.urbanforestrysouth.org/resources/library/ttresources/vegetation-risk-management-plan-template-with-attachment/at_download/file

Central Alabama Regional Planning and Development Commission. January 2013. "UTRI Data Process and GIS Tool Description." Available at www.urbanforestrysouth.org/resources/library/ttresources/utri-data-process-and-gis-tool-description/at_download/file

  • A tool intended to help improve public safety and tree health after a storm event and a narrative description of the Urban Tree Risk Index model.

Colorado State Forest Service. February 2013. "Replanting in Burn Areas: Tips for Safety and Success." Available at http://csfs.colostate.edu/pdfs/FINAL-Post-FireReplanting-andSafetyTips-2013Feb11.pdf

  • Recommendations for people planning to plant seedling trees to reforest areas burned by wildfires.

Defenders of Wildlife. 2012. Harnessing Nature: The Ecosystem Approach to Climate-Change Preparedness. Available at www.defenders.org/publications/harnessing-nature.pdf.

  • A look at using natural methods for battling the effects of climate change. Includes case studies of forest restoration after wildfires in California and the lowland Southeast.

Dunster, Julian A., E. Thomas Smiley, Nelda Matheny, and Sharon Lilly. 2013. Tree Risk Assessment Manual. International Society of Arboriculture. Available at www.isa-arbor.com/store/product.aspx?ProductID=442.

  • A manual for expert and novice risk assessors, and the companion publication for the Tree Risk Assessment Qualification course.

Duryea, Mary L., Eliana Kampf, and Ramon C. Littell. March 2007. "Hurricanes and the Urban Forest I: Effects on Southeastern United States Coastal Plain Tree Species." Arboriculture & Urban Forestry. 33(2) : 83-97. Available at http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=2982&volume=33&issue=2&Type=1

Duryea, Mary L., Eliana Kampf, Ramon C. Littell, and Carlos D. Rodríguez-Pedraza. March 2007. "Hurricanes and the Urban Forest II: Effects on Tropical and Subtropical Tree Species." Arboriculture & Urban Forestry. 33(2) : 98-112. Available at http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=2982&volume=33&issue=2&Type=1

  • Two studies looking at the impacts of hurricanes on the urban forest in Southeastern U.S. coastal plain tree species and tropical and subtropical tree species. Examines factors relating to survival, branch loss, and leaf loss.

Federal Emergency Management Agency. July 2007. FEMA-325, Public Assistance: Debris Management Guide. Available at www.fema.gov/pdf/government/grant/pa/demagde.pdf.

  • Information on how to develop a comprehensive debris management plan.

Hauer, Richard J., Weishen Wang, and Jeffrey O. Dawson. 1993. "Ice storm damage to urban trees." Journal of Arboriculture.  19, no. 4: 184-194. Available at http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=2563&Type=2

  • A damage survey of parkway trees in Urbana, Illinois, following a severe ice storm. Examines different tree factors that lead to more or less ice damage.

International Society of Arboriculture. 2013. Basic Tree Risk Assessment Form. Available at www.isa-arbor.com/education/resources/BasicTreeRiskAssessmentForm_FirstEdition.pdf

  • A standardized checklist and categorization form for evaluating tree risk.

Luley, C. J., and Jerry Bond. 2006. "Evaluation of the fate of ice storm-damaged urban maple (Acer) trees." Arboriculture & Urban Forestry 32, no. 5: 214-220. Available at http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=2958&Type=2

  • A consideration of the removal of ice-damaged trees. Concludes that urban tree managers should look at tree species as an important factor in making removal decisions after an ice storm.

Madren, Carrie. Fall 2012. Recovering from Disaster. Available at www.americanforests.org/magazine/article/recovering-from-disaster/

  • Examines several different types of natural disaster that can impact forests and how they can recover. Includes short sections on flooding, hurricanes, ice storms, and volcano eruption.

Olwig, M. F., M. K. Sorensen, M. S. Rasmussen, F. Danielsen, V. Selvam, L. Hansen, L. Nyborg, K. Vestergaard, F. Parish, and V. Karunagaran. July 2007. "Using Remote Sensing to Assess the Protective Role of Coastal Woody Vegetation Against Tsunami Waves." International Journal of Remote Sensing. 28: 3153-169.

  • A comprehensive analysis of the effectiveness of mangrove trees for hazard mitigation. This study used the Indian Ocean tsunami of 2004 as a control group to establish a baseline for effectiveness of vegetation. The results were overwhelmingly in favor of densely forested areas being an effective hazard mitigation tool.

Pokorny, Jill, Joseph O'Brien, Richard Hauer, Gary Johnson, Jana  Albers, Peter Bedker, and Manfred Mielke. 2003. Urban Tree Risk Management: A Community Guide to Program Design and Implementation. U.S. Forest Service. Available at www.na.fs.fed.us/spfo/pubs/uf/utrmm/index.htm.

  • A tree risk training manual written for community leaders, administrators, city foresters, parks and public works staff, and private tree care practitioners.

Sisinni, S. M., W. C. Zipperer, and A. G. Pleninger. 1995. "Impacts from a major ice storm: street-tree damage in Rochester, New York." Journal of Arboriculture 21: 156-167. Available at http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=2678&Type=2

  • A study using data from a comprehensive public tree survey following a major ice storm looking at responses of urban trees to severe glaze accumulation.

Smiley, E.T., N. Matheny, and S. Lilly. 2011. Best Management Practices: Tree Risk Assessment. International Society of Arboriculture. Available at www.isa-arbor.com/store/product.aspx?ProductID=324.

  • A guide for arborists to assess and evaluate tree risk and to recommend measures that achieve an acceptable level of risk.

Tree Care Industry Association. "ANSI A300 (Part 9) – 2011 Tree Risk Assessment." Available at http://tcia.org/business/ansi-a300-standards/part-9

  • A standard for tree risk assessment designed to help state and local governments manage risk for public trees.

University of Arkansas, Division of Agriculture, Research & Extension. "Natural Disaster Recovery in Arkansas." Available at www.uaex.edu/environment-nature/disaster/.

  • Includes sections on the impact of drought, flood, and storms on forests, as well as one on salvaging timber after a disaster. Incorporates links to useful reports and documents.

Vidos, Kris. September 9, 2013. Trees: Storm Preparation and Recovery. Available at http://ncptt.nps.gov/blog/preparing-trees-for-a-major-storm-and-recovery-of-culturally-significant-trees-after-a-disaster/

  • Video and transcript of a presentation by Debbie Smith, chief of the historic landscapes program at the National Center for Preservation Technology and Training. She offers advice on how to prepare trees for a storm and how to recover after a disaster.