Ashton Preserve, Montgomery County, MD Natural Resource Inventory / Forest Stand Delineation

Ashton Preserve is a planned 176-acre, rural residential cluster subdivision of estate homes to be constructed in Montgomery County, Maryland. Prior to conceptual and preliminary site planning ESA performed a natural resource inventory (NRI) and forest stand delineation (FSD) which inventories and describes existing forest and locates priority areas for retention and reforestation. The FSD became the methodology for evaluating the existing natural features and vegetation on the site.


The ESA study protocol involved the delineation of all forest stands and their acreage within the property boundaries. Forest stand description was based on species composition, density, size, condition and age of the stand. The dominant, co-dominant and associate tree species for each stand were identified and tabulated to indicate their relative frequencies and average tree diameter class along with descriptions of each tree stand including the identification of the understory and herbaceous species. This information was utilized to isolate stands of higher quality vegetation (i.e. old growth, riparian or contiguous forest) and individual specimen trees, groves and clusters that were considered for potential preservation during the planning process.

Wetland delineation was also performed, coupled with NRI ground-truthing, allowed for mapping to be prepared that documented wetland boundary, stream valley setbacks (county regulation which requires a 250-foot vegetated protection buffer on recreational trout streams), steep slopes, highly erodible soils, rock outcroppings, spring seeps and floodplain. Our rare/threatened/endangered (RT&E) survey work documented 'watchlist' species of shingle and Lea's oak occurring on the property along with unique hellebore/skunk cabbage seeps. These combined map overlays provided planners with an 'amenities versus constraints' feasibility baseline from which to design from.

Due to the high quality nature of the streams, regulatory wetland and stormwater management (SWM) permitting required that ESA assist in the bio-sensitive design of SWM that included stacked, redundant, multi-trained best management practices that included groundwater recharge infiltration systems and one-year discharge controls (to eliminate the storm pulse of a volume and velocity that causes bank erosion on the receiving stream). ESA prepared a 'bio-engineered' stream restoration plan that included rock ford crossings for proposed network of equestrian bridle and foot t rails that ESA also design/built. Housing lot and street layout for this project is incorporating numerous elements of NRI/FSD mapping to preserve and protect natural resources and will further increase the perception of quality and maturity of individual multi-million dollar homes.

ESA employees were major contributors in the preparation of the Maryland State, Technical Forest Conservation Manual and developed and taught course curriculum for the Maryland Department of Natural Resources with their Qualified Forestry Professional program statewide. Two ESA employees maintain qualified status in the State of Maryland for the preparation and submission of Forest Stand Delineation and Forest Conservation Plans.