It’s hard to imagine, but most of Vermont’s forests and hillsides were clear-cut in the 19th-century. Still, while 80 percent of the state had been deforested, a handful of Vermont’s old forests miraculously survived. Some of those old trees—more than 300 years old—can be seen today at Gifford Woods State Park in Killington. Gifford Woods State Park, established in the 1930s, contains one of Vermont’s few old-growth hardwood forests. Near the park’s entrance along Route 100, a trail built by the Civilian Conservation Corps—which became an interpretive trail in 2009—meanders through the woods along picnic areas and campsites. The trail…