A paving project designed to extend the life of pavement on the Blue Ridge Parkway in Virginia will create some snarls on the scenic road beginning July 5 and lasting for about three months.

Twenty years ago, the Blue Ridge Parkway Foundation started as a simple idea: Give the people who care deeply for the Blue Ridge Parkway the power to protect and guide its future. Whether they cherished the trails, overlooks, ties to mountain history and culture, wildlife, or just the drive itself, they were invited to support the historic scenic route.

The spine of the Appalachian Range runs north and south through the Mid- and South-Atlantic states, a rumpled stretch of mountains that long has provided a corridor for species. One uninvited species, the Hemlock Woolly Adelgid, arrived in 1951, and since then has attacked hemlock forests once commonplace in Shenandoah National Park, the Blue Ridge Parkway, and Great Smoky Mountains National Park. Since 1988 the National Park Service has been battling the tiny insect, and has met with varying success in those three parks. While much work remains to be done, there is optimism some of the hemlock stands will be saved. In the following stories, we take a look at the campaign.