Tree Canopy

What is Tree Canopy?

Tree canopy is the land area that is covered by tree trunks, branches, and leaves. It can be measured using satellite imagery and elevation data.

Why Do We Measure It?

We live in an urban forest, where trees provide many benefits to us and the wildlife around us. This canopy changes over time, and measuring it on a regular basis can help us understand trends and where we may need to focus planting and conservation efforts. This need to understand changes in our tree canopy led to recommendations in the Forestry and Natural Resources Plan (FNRP) to monitor changes every 3-5 years (Action step 4.1.1), and to understand our progress in Tree Equity Areas (Action step 2.1.1).

Changes in tree canopy can decrease from removal or death of trees and increase from the growth of existing trees and planting of new trees.

2023 Tree Canopy Report

A study was conducted after the approval of the FNRP, using 2023 aerial imagery and elevation (LiDAR) data. The study required 99% accuracy for the tree canopy data. Additionally, the County looked at data for 2014 and 2018, using the same analysis methods and accuracy, to understand change over time. Arlington’s tree coverage in 2023 was 35.2%, up from 31.7% in 2014 and 33.3% in 2018. This progression supports Arlington’s goal to reestablish and maintain at least 40% tree canopy County-wide.

Find more details in the report, available here(PDF, 3MB). To learn more about the report, watch this recording of our Tree Canopy Virtual Information Session (Dec. 12, 2024).

Below you can see interactive maps of how tree canopy may have changed in your neighborhoods. Click on map to launch viewer.

Data on tree planting and removal from County operations and permitted projects can also be explored on the County's Open Data Portal.

Goals

The FNRP has a target to Reestablish and maintain at least 40 percent tree canopy county-wide through conservation and tree-planting programs tailored to local conditions and ecological contexts. (Action step 1.1.1). This is in line with regional goals set by the Metropolitan Washington Council of Governments, to reach 50% regionwide, where densely-urbanized counties are encouraged to set goals between 35-45% to achieve these goals.

How Can We Improve Tree Canopy?

• Conserve trees on your property, or properties you have influence on (such as schools, churches, places of business). The following links can help you achieve this:
  • Virginia Tech Extension – For questions about tree care, health and diseases
  • Tree Stewards – To learn about and volunteer in Arlington to conserve trees
  • Find an arborist – To find certified arborists who can give you advice on tree care
  • Avoiding tree damage on your property
• Plant trees on your property, or properties you have influence on (such as schools, churches, places of business). The following links can help you achieve this:
  • Tree Canopy Fund – get a free tree planted
  • Tree giveaway – Pick up trees to plant
  • Native Plant Nurseries – Find a nursery for native trees
  • Request Service – Request a tree to be planted on public land
• Educate your neighbors, family, and friends about the benefits of trees
  • Tree Stewards – Volunteer to educate the public at events throughout Arlington
  • Forestry and Natural Resources Commission – Attend or become a commissioner, to help guide the County Board on tree and natural resources issues
  • The Nature Conservancy – 6 ways trees benefit our lives
  • Arbor Day – Learn more about the benefits of trees

Historic Reports

Tree canopy analyses started in 2008, with a study performed by Virginia Tech, followed by a 2011 regionwide study performed by the University of Vermont, and a 2016 study performed by Davey Resource Group. These reports use different methodologies and generally have a lower level of accuracy than the 2023 study.