Tree Care

2. A Second Row of Trees in the ‘Parking’

Where tree canopies meet, pests can spread.

RMA works to regrow the canopy of mature trees that, a century ago, arched majestically over Mass Ave sidewalks. So when the willow oaks and pin oaks in the 2500 block of Mass Ave were threatened by oak lecanium scale, we had them innoculated against this pest.

Most of the hundreds of trees RMA has planted and cares for are lindens, elms and some oaks in a  family not targeted by this pest.  Go to our grand avenue species page to ID and enjoy the trees here!

To treat the twelve sidewalk street trees and “second row” trees in lawns which were attacked by this scale, we hired Bill Eck of Bartlett Tree Expert Company in Gaithersburg, Md.

Injection with Lepitect infusible was chosen instead of spraying because, Eck said, “the commonly accepted treatments for street trees, soil drench of imidacloprid or bark spray of dinotefuran, have been resulting in failures, especially on large trees.”  RMA President Deborah Shapley stressed that whether to treat affected trees at all (since scale often dies back naturally) or use injection or spray should be decided by experts. For more see our September 28 Press Release, “Pest Harming District’s Willow Oaks”.

The treatment over a single day in August is likely to help the trees survive and do well next season, Eck said, though the future of the large pin oak shown here is in doubt.

RMA’s project can be a model for how DC neighbors get together to address groups of trees, such as city street trees and trees in adjoining public land called “the parking.”

At right is an allée of willow oaks RMA had planted in 2007, which were treated. The left row are city street trees. At right are four oaks – willow oak and overcup oak – we planted with Casey Trees. We are delighted that these second row oaks in the “parking” were protected from the spread of this pest from nearby trees.

What is the “parking”?

Most of Washington DC’s streets have public land between the sidewalk and the private property line (which is usually the building line). City leaders in the 19th century set aside these long street edges aside to be “parking” – meaning park land, not cars! The other term still in use is “public parking” which shows they envisioned it as a general amenity, not individual private yards.

Though the “parking” is public space, by law and regulation it is maintained by the adjacent property owners. Owners may enjoy the land, such as by planting and maintaining trees but must comply with city laws and rules.


Click to enlarge | Click to view/download pdf


In the graphic, tree on the left is a sidewalk “street tree” planted by the city.

Tree on the right is a second row tree in the 40’ deep “parking” of Mass Ave.

Trees and other improvements are the adjacent property owners’ responsibility.

Green, parked streets define Washington’s character as much as the building height limits.

Definitions and rules are at DCMR T24-102, 24-103 and 24-104

For Historic Districts such as the Massachusetts Avenue Historic District, consult the Historic Preservation Office in the Office of Planning

Questions? Consult the Office of Planning, DDOT,

What can I plant there? What are my obligations?

  • Owners of abutting property are to maintain this land and may choose trees and landscape, subject to city and federal rules. DC Act 14-614 106 (b)
  • Hedges and fences should be 3.5’ high or less. DCMR T24 103.3
  • Foreign owners of land have same obligation maintenance of the “parking,” including trees, as US owners Foreign Missions Act, 22 US Code ¶ 4301- ¶ 4316

I need ideas for how to “green” my street.


Go to Project 3 – Expand the Urban Forest and Save Energy»