Study Shows Tree Canopy Loss
The U.S. Geological Survey’s Chesapeake Bay Program in partnership with the U.S. Forest Service, Chesapeake Bay Conservancy, and states in the watershed recently released data summaries from their extensive mapping efforts of the Chesapeake Bay watershed of which Rockbridge, and 60% of Virginia’s land area is a part.
The results show that between 2014 and 2021, Rockbridge County lost 589 acres of tree canopy cover. Most of this loss occurred in the populated areas of the county running the length of the I-81 and U.S. 11 corridors. There were 452 acres of tree canopy converted to turf or “pervious surface” uses and 228 acres of tree canopy that are now impervious surfaces (developed). There were 64 acres of open land in Rockbridge where tree cover was gained and 27 acres of impervious surface that came under a tree canopy in the same seven-year period. These 27 acres are still mostly impervious surface but the imagery shows strategically placed trees have successfully grown and provided cover for these areas. The accuracy and sophistication of satellite imagery available to the public has allowed this analysis and the work of state and federal personnel accomplished the ground-proofing and sampling to verify the results.
In Rockbridge there are few, if any, specific sites we can point to blame for this loss of tree canopy. Rather it appears to be a function of simple population and development pressure that has removed trees dispersed over a large area of the county. Interestingly, our forested areas where tree harvesting takes place showed very little change. Generally, timber harvesting as it has been conducted in Rockbridge in recent decades, has had minimal impact on our total tree canopy in the county.
Your columnist suggests that the take away point is that trees make our communities better and sustaining the functions, and services trees provide demands conscious effort and planning. In the right place, tree removal can be the right natural resource decision. In other places, like surrounding our streams and springs or strategically located to slow the movement of water across slopes, we need more trees.
As our population grows, some tree canopy loss is inevitable. This makes intentional tree placement, cultivation, and management all the more important.
An excellent report on tree canopy status and stewardship in the Chesapeake Bay watershed was published in the Virginia Mercury in a September 29 written by Evan Visconti (https://virginiamercury.com/ category/energyenvironment/). More information on the watershed mapping project and access to county-level tree canopy reports are available at https:// chesapeaketrees.net/understandyour- canopy/. Printed copies of ‘Tree Cover Status & Change for Rockbridge County, VA 20142021 are available at the Rockbridge County Extension office.
