How Are Trees Doing 5 Years After Development? A Tree Steward Project.

We are all dismayed to see so many trees removed when an old house is torn down and a new one built. Yes, Arlington County has regulations requiring preservation and replanting, yet we wonder if these are sufficiently followed? This summer six Tree Stewards conducted a pilot project of 32 such sites under the direction of Urban Forester Vincent Verweij to determine the answer to this question. The pilot project was so useful, so we plan on repeating it soon.

Yep, that river birch is on plot and they added an extra Magnolia!

The volunteer work was fun and instructive. First, we learned how to read the intricate site plans required at each development so we could tell how many trees should have been conserved, and how many new plantings should have been installed on what spot in the property.  Then in pairs we went to that address, knocked on the door, and asked if we could count their trees. Sometimes the homeowner welcomed us, proudly showing off their beautiful trees conserved, planted during development and those they’ve added over the five years! Some were skeptical and refused admittance to the property, and many were not home leaving us to determine how many trees existed on the property from public sidewalks. We must have looked strange to neighbors, wearing our yellow TS vests, standing on tip toe to see over fences, and making notes on clipboard!

The pilot project process will be improved for the next time:

  • More TS will be recruited and trained for the next survey to be scheduled soon
  • The reporting sheet has been revised for clearer definitions  
  • An initial letter on TS letterhead describing the project will be sent to all homeowners
  • information on TS and tree maintenance will be left with each homeowner

The results show good news in that 233 trees have been planted in the last 5 years; however, the unhappy news is that only 46 of the 83 originally conserved old trees on site still survived after 5 years.

A more thorough description of the project and the results are as follows:

In 2018, 320 private properties were developed in Arlington County.  The Chesapeake Bay Preservation Ordinance requires a Landscape Conservation Plan for any site disturbance greater than 2,500 sq. ft.  Department of Parks and Recreation forestry staff reviews and enforces the requirements of the Landscape Conservation Plan.  Residential properties must demonstrate how the site will have 20% forest canopy in twenty years. This can be achieved by using existing trees or trees proposed for planting. 

For each of the 320 properties, a site plan was required by the County which showed 1) the trees to be removed due to construction, 2) the trees to remain after construction (conserved trees), and 3) any trees that need to be planted to provide the 20% canopy density after twenty years (planted trees)if the credit for conserving existing trees is not sufficient.  Note that this requirement only applies to the development of the property, and legal restrictions to removal of trees after the completion of the development may be limited.

An Anonymous plan sample. Tree Stewards worked from larger originals comparing the plan to the current yard.

A tree survey was conducted in 2023 to ascertain the effectiveness of the 2018 Landscape Conservation Plan.  This allowed for five years between site development and the present, which provides information on long-term trends in compliance with the Preservation Ordinance. Ten percent of properties developed in 2018 (32) were randomly selected, and pairs of Arlington County Tree Stewards approached property owners and asked permission to delineate the trees currently on the property.  Of the 32 properties visited, 4 were not able to be surveyed because either permission was not granted, or nobody was home on multiple visits and the property could not be assessed from the road.  

The results of the survey show that 55% of the conserved trees (i.e., trees present which were to remain according to the site plan) were still present in 2023 (46 of 83 trees), and 86% of the trees that were required to be planted were present in 2023 (117 of 136 required trees). In addition, 163 additional trees were planted; however, many of these were not canopy trees (arbor vitae, crepe myrtle, etc.).  In addition, 11% of the properties had more conserved trees than were on the plan (i.e., not all trees slated to be removed were cut down) 14% of the properties had more trees planted than were required in the site plan (an additional 163 trees were planted).

Photos for this blog post were provided by Steve Geiger and Nora Palmatier

About TreeStewards

TreeStewards of Arlington and Alexandria, Virginia, are trained volunteers who work to protect, preserve, and enhance urban tree canopy through public education and volunteer activities such as planting, pruning, and caring for trees.
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1 Response to How Are Trees Doing 5 Years After Development? A Tree Steward Project.

  1. Nancie Connolly says:

    This was a great undertaking by Tree Stewards and it reflects well on the collaboration between the county and TS.

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