According to an October 1 article in the Bay Journal by Timothy Wheeler, data from aerial surveys sponsored by U.S. Geological Survey, and the U.S. Forest Service, indicates that the Chesapeake Bay watershed continues to lose significant tree canopy. Between 2013 and 2021, the watershed, which includes Loudoun County, lost approximately 49.5 square miles of tree cover. Over the same period, development covered an area of almost 200 square miles with roads, rooftops, parking lots and other impervious surfaces.
The aerial surveys are part of a federally funded effort to map and track changes in land use and land cover across the Bay watershed
According to the Chesapeake Tree Canopy Network between 2014 and 2021 Loudoun County lost 3,400 acres of tree cover. Of that 54% was lost to impervious surfaces increasing storm water runoff. The Loudoun County tree canopy removes approximately 8.8 million pounds of air pollutants annually, sequesters 177,000 tons of carbon annually, and reduces storm water runoff by 475.4 million gallons annually for a total financial value of $93.2 million annually.
Friends, continues to urge Loudoun County to amend the existing zoning ordinance to provide better protections against development in the Blue Ridge Mountains and to strengthen tree clearing regulations.
Trees provide many benefits to the Bay watershed. They help clean the air, filtering harmful particulate pollution and consuming climate-warming carbon dioxide. They reduce stormwater pollution and help control flooding by soaking up rainfall. They reduce erosion, and they provide cooling shade to streams and communities. They provide food and habitat for birds and other wildlife.
Impervious surfaces contribute to reduced water quality and destroy aquatic life. Rain on roads, rooftops and sidewalks runs off and carries pollutants like excess fertilizer, pet waste, toxic chemicals and litter to the nearest waterway and ultimately to the Chesapeake Bay. Impervious surfaces also absorb the sun’s radiation, heating stormwater runoff and raising stream temperatures — often to a degree that many fish, amphibians and aquatic insects can no longer live there.
The aerial survey shows that the amount of the Bay’s watershed covered by impervious surfaces expanded by approximately 20 square miles, every year from 2013 through 2021.
The Chesapeake Tree Canopy Network is a collaboration of the Chesapeake Bay Program Forestry Workgroup, the US Forest Service, and the Alliance for the Chesapeake Bay. It maintains a detailed database with information about the tree canopy and changes in it throughout the entire Chesapeake Watershed. Data is available county by county and for each municipality. Access the data base at https://chesapeaketrees.net/understand-your-canopy/