In an effort to reverse the effects of the chestnut tree blight of the 1950s, the first American Chestnut/Fall Farm Festival, noon to 4 p.m. Saturday, will demonstrate the value of the tree as wood and as a fruit. The Nationl Colonial Farm, a re-creation of a mid-18th century tobacco farm, will host the festival, offering demonstrations of chestnut woodcraft, chestnut wreath making and chestnut pancakes making, plus Colonial crafts and children's games, music, storytellers, carriage rides and tours of the farm and its chestnut gove. Refreshments and chestnuts will be for sale. Admission is $2 for adults, 50 cents for children. The farm is at 3400 Bryan DPoint Road in Accokeek. Call (301)283-2113.