The Nashua River Watershed Association will be leading a guided trail walk at the Heald Street Orchard in Pepperell at 1 p.m. today. Heald Street Orchard is an 80-acre conservation area owned by the town of Pepperell that features an apple orchard, grasslands, and woods adjacent to Heald Pond. The trail walk will last about one hour and cover 2 miles. The walk is free and open to the public, funded in part by a grant from the Nashoba Valley Community Healthcare Fund. Parking is located on Heald Street approximately 1¼ miles from Pepperell Town Hall. To register, contact Al Futterman at the Nashua River Watershed Association, 978-448-0299, or e-mail AlF@NashuaRiverWatershed.org.