Greenbelt National Park needs help cleaning park grounds on April 19 at 10 a.m. Call at 301-344-3944 or visit www.nps.gov/gree/.

Christmas in April urgently needs plumbers and plumbing supplies to repair the residences of 102 disadvantaged homeowners April 26. Also needed are donations of lumber, paint supplies, appliances, and electrical and roofing materials. 301-868-0937.

Family Tree of Maryland needs help to prevent child abuse and neglect by working to strengthen and educate families. Volunteers are needed to mentor teenage parents and families, teach parenting classes, assist with support groups, direct children's programs and staff a 24-hour crisis and referral hotline. Training provided. 301-209-5254.

Greenbelt National Park, inpartnership with the University of Maryland, needs help in protecting the park from harmful invasive plants. People interested in nature preservation are asked to help remove such plants in the park on the first Saturday of each month (spring through summer) at 11 a.m. rain or shine; appropriate clothing and work gloves are required; bring lunch and a snack. The ranger station needs outgoing, friendly people to help greet visitors from around the world, answer phones and do light administrative duties. Must be English-literate and work a three-hour shift Fridays, Saturdays or Sundays. The position qualifies for Student Service hours. For more information or to schedule an interview, call 301-344-3944.

Habitat for Humanity seeks skilled and beginning-level carpenters, plumbers, electricians, dry wall mechanics, bricklayers, roofers and office workers to help build a house in Camp Springs. 301-779-1912.

His Lordship's Kindness, a National Historic Landmark House in Clinton, seeks help with programs, tours and activities, including historic interpretations, costume making and the annual Easter Egg Hunt. 301-856-0358.

Jwanzaa Youth Partnership needs adults willing to donate two hours per week to mentor children 7 to 17 in Prince George's. Orientation and ongoing training provided. Excellent opportunity for adult students majoring in human service. 301-324-9705.

Marietta House Museum in Glenn Dale has positions for tour guides, a museum shop salesperson and special events support. Tour guides are needed for one four-hour shift a month on Saturday or Sunday noon to 4 p.m. Training provided. 301-464-5291.

Meals on Wheels of Central Maryland needs people to deliver meals to homebound residents of Laurel. Valid driver's license required. Call Elizabeth Yan, 410-730-9476.

Department of Social Services needs help for special events, clerical work, sorting donations and delivering to the homebound. For more information and to request an application, call 301-909-6319.

Retired and Senior Volunteer Program invites adults 55 and older to help children learn to read, prepare meals for the homebound and provide support to nonprofit agencies in many capacities. Call Ivin Myles, 301-699-2797.

-- Barbara Hinton

If you want to volunteer, contact the agencies directly. If you have an item for Volunteers, e-mail it to pgextra@washpost.com; fax to 301-952-1397; or write to Volunteers, Prince George's Extra, The Washington Post, 14402 Old Mill Rd., Suite 201, Upper Marlboro, Md. 20772.