The Trustees of Reservations organization is looking for volunteers to help replace the Echo Pond footbridge in the Rocky Woods preserve, starting at 9 a.m. Saturday. The long, narrow footbridge is part of a half-mile trail looping around the pond in the 491-acre property off Hartford Street; Rocky Woods is a popular family destination for hiking, catch-and-release fishing, and other outdoor activities. Volunteers also will help construct a safer, wider bridge with railings, supported by a grant from REI, the outdoor gear company. On Saturday, volunteers will begin removing the old bridge. After the old bridge is gone, volunteer crews will cut lumber and then assemble the new bridge in phases spread across Wednesdays and Saturdays this summer. Due to the nature of the project, the number of participants is limited. Contact the Trustees of Reservations at least one day before to register and sign up for e-mail updates at email@example.com or call 508-785-0339.