Welcome back to CSN’s Stormwater Spotlight Series! Over the next few months, we will be showcasing some of the top BUBBAs projects from this past year. Up next we are in Fairfax County. Virginia to learn more about the winner of our Best Habitat Creation category: The Fairfax County DPWES Stormwater Reforestation Project! Here are a few excerpts from their project narrative:

The Fairfax County Department of Public Works and Environmental Services (DPWES) Stormwater Program is leading a reforestation project to convert over 430,000 square feet (10 acres) of county parkland from turf grass and non-native invasive species to forest. They are utilizing innovative planting methods and locally native plant palettes to provide water and air quality, wildlife habitat and human quality of life benefits.

To identify candidate sites, stormwater staff worked closely with the Fairfax County Park Authority. Sites were evaluated based on accessibility, current land cover, available planting areas, adjacent land cover and planting limitations such as presence of utilities or planned future park uses. The ability to control existing non-native invasive (NNI) plant species was another significant consideration. All-told, over 200 acres of candidate sites were identified and reforestation easements were placed over the planting areas on selected sites to protect them in perpetuity.

Silas-Burke Planting Site, June 2018.

To establish restoration goals and select plant species, each site was evaluated for the potential climax native vegetative community based on the soils, landscape position and surrounding vegetative communities. A target community was then selected from the Virginia community classifications as defined by the Virginia Department of Conservation and Recreation Natural Heritage Program. Initial woody planting densities were ~150% of the required 300 trees per acre to match the Chesapeake Bay Expert Panel guidance on reforestation to account for transplant shock and site/species fit. Species selection included two components:

  1. A woody plant palette containing:
    1. Climax species for the targeted vegetative community;
    2. Early succession species to provide appropriate habitat, compete with NNIs and act as nurse plants for the several decades it takes for the climax species to dominate; and
    3. Plants that deer do not prefer to use on the exterior of planting clumps to minimize browse.
  2. An herbaceous seed mix to provide a high quality meadow base community between woody plantings that can compete with NNIs, restore soils through establishment of dense root systems and associated soil organisms, and provide water quality, aesthetic and wildlife benefits.

Through research, interviews with several restoration planting professionals and experimentation, a clump planting methodology was developed to place climax species and more deer-palatable, early-succession species on the interior of the clumps while locating the more deer-resistant plants on the outer perimeter. An experimental design pairing clumped plantings with traditional random distribution plantings was used at the larger reforestation sites, while more traditional distribution plantings were used at smaller sites.

Super Clump Planting Layout: Fairfax County DPWES

Monitoring is conducted annually to gauge restoration success and to determine what adaptive management actions may be necessary to maintain the restoration sites.

To learn more about the program, please check out our archived webcast from September 12, 2019: “Stormwater Roots: Reforestation”.