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File #: 22-3399    Version: 1 Name:
Type: Conference Session Item Status: Agenda Ready
File created: 9/26/2022 In control: Town Council Conference Session
On agenda: 10/17/2022 Final action:
Title: Presentation of Urban Tree Canopy Assessment Report
Attachments: 1. 1. Regulatory Requirements for Agenda Items- Urban Tree Canopy Assessment 2022, 2. 2. Vienna Urban Tree Canopy Assessment Report 10.4.22, 3. 3. VIENNA - 1937, 4. 4. VIENNA - 1960, 5. 5. VIENNA - 1990, 6. 6. VIENNA - 2011, 7. 7. VIENNA - 2022



Presentation of Urban Tree Canopy Assessment Report



In August 2021, Vienna applied for and was awarded a matching federal grant of $7,500 from the Virginia Department of Forestry and the U.S. Forest Service to conduct and complete an urban tree canopy assessment. The purpose of the project was to help the Town prepare an urban forest management plan, set a tree canopy goal and measure progress toward mitigating and reversing tree loss in the Town.
On October 11, 2021, council approved the agreement to conduct the Urban Tree Canopy Assessment.  Davey Resource Group was awarded the contract to complete the assessment. Scott Diffenderfer, Town Urban Arborist, led and managed the project.

Town Comprehensive Plan - Chapter 8 - Environment and Sustainability

Town’s goal is to:

                     Protect and enhance the existing tree canopy in residential neighborhoods and commercial zones.

                     Protect, restore, and enhance the Town’s watersheds.


Town Code Chapter 27.4 - Conservation and Sustainability Commission - Powers and Duties -

B. (6) To develop and recommend policy initiatives and changes to the mayor and Town Council that promote a sustainable community to include tree protection and replacement programs.

D. (10) To plan and promote programs and events that further the mission of the commission through the following: Serve as the Town tree board and maintain Tree City USA status for the Town.


Town Code Chapter 27-5.  - Conservation and Sustainability Commission - Tree Board - 

(a)The Conservation and Sustainability Commission, acting with the cooperation and advice of the ISA certified Town arborist, shall constitute the Town tree board.

(b) The tree board shall have the following powers and duties:


1. To promote and protect public health, safety, and general community appearance by planning and recommending the planting, maintenance, and removal of trees, shrubs, and other plants on public property within the Town.

2. To ensure that the planting, maintenance, pruning, and removal of trees and shrubs on public property within the Town are done in accordance with current accepted standards as established and set forth by the National Arborist Association and by the American Association of Nurserymen's Council American Standard for Nursery Stock.

3. To develop, maintain, and administer a written plan for the care, preservation, pruning, planting, replanting, removal, or disposition of trees and shrubs in parks, along streets, and in other public areas. Such plan will be reviewed annually, updated as necessary, and presented to the Town Council; upon acceptance and approval by the Town Council, such plan shall constitute the official public tree management plan for the Town.


4. To recommend to the Town Council and to the appropriate municipal department directors the adoption of such rules, regulations, and policies as may be necessary to implement and enforce the public tree management plan and related ordinances.

5. To undertake an ongoing program of public outreach and education in order to promote public understanding and support of the Town's public tree management plan and to increase public awareness of the value and benefits of a diversified, sustainable community forest.



Davey Resource Group, with Town guidance, established that the primary goals of the assessment are to establish baseline data on the extent and function of the existing urban forest, compare current canopy data (2021) to levels seen in the past, and provide a resource to guide future community forest management efforts.  They completed their study and analysis of current aerial imagery demonstrates that currently tree canopy covers 38.7% of Vienna, approximately 1,090 acres.  In comparison to 2011 imagery, Vienna’s current tree canopy cover has been reduced by approximately 163 acres, a percent change loss of 13%.  The study analyzed suitable areas for future planting and were ranked based on the benefits that additional canopy coverage would provide.  Approximately 214 acres of planting areas were identified as “Very High” and “High” classifications of potential canopy, which if planted would represent a percent change increase in canopy cover of 19.6%.



Based on the completed Urban Tree Canopy Assessment Report, staff proposes the following Town goals:

                     Establish a percentage for the Town’s tree canopy goal.  The national average is 39%. 

                     On private land parcels undergoing development, establish a 20% tree canopy coverage in 10 years.  Currently the Town’s policy is 20% tree canopy coverage in 20 years.  The Town has proposed this change to the Virginia state legislators a number of times with no success.  20% tree canopy coverage in 10 years is a Fairfax County requirement.

                     Develop a Tree Preservation and Planting Fund - if builders are unable to plant enough trees on on-site to meet the tree canopy requirements, funds can be collected to plant trees on public property thereby helping to meet the 20% tree canopy coverage just not completely on their building site.

                     Establish bonding for trees installed to fulfill the tree canopy coverage requirement - ensures the landscape planting survives the first year.  There is currently no bond required for new tree planting. 

                     Develop a Vienna Tree Citizen Involvement Program led by the Conservation and Sustainability Commission - would generate public engagement and encourage residents to plant on their private property.

                     Establish an Urban Forestry Management Plan (UFMP) to identify and detail the scope of managing the total tree canopy of the                      Town of Vienna.  This includes tree inventories, tree preservation (not only during construction but at all times), tree planting, staff and equipment needs/recommendations and applicable policies associated with tree canopy preservation.  This would be a 5-year plan with 3 phases and detailed on a timeline.

                     Ensure the Town’s Urban Arborist is involved at the beginning of the planning process with developers and builders.  This is primarily aimed at subdivisions, commercial, and multi-use sites.  Currently, the Urban Arborist gets a notification for these plans after the plans are submitted for preliminary review.  It would be best if the Urban Arborist was brought in during the pre-plan submission phase.

                     Delineate three distinct divisions within the Parks Department to include Urban Forestry Maintenance, Horticulture and Parks Maintenance.  In order to achieve success with the Town of Vienna’s Urban Forestry Management Plan, it is recommended that the Urban Forestry Management Division have in-house staff with technical expertise that will allow for reactive and preventative tree maintenance. The Town currently has no dedicated staff with the technical expertise to perform intricate tree maintenance work. Urban Forestry staff would be responsible for public tree maintenance including pruning, removal, pest and disease treatment, tree installation, watering, mulching, stump grinding, elevating or clearing branches from streets, sidewalks, signs, signals, street lights, etc.   By having in-house staff, the cost of caring for the trees will be less than contracting.

                     Recommend conducting another Tree Canopy Assessment Study in 5 years.  This will provide accurate data to determine if the Town’s tree canopy coverage requirement is increasing the Town’s overall canopy percentage.



Recommended Action

Staff recommends that Council discuss the study results, review staff recommendations and provide guidance on supporting the staff goals.