WASHINGTON (AP) — More than 3000 musicians, singers, dancers, instrument makers, Indians and others have assem bled for the 34th annual Nation al Folk Festival senate today at Wolf Trap Farm Park. For the next three days they will take part in workshops and concerts nightly in the Filene Center, the amphitheater at the first national park devoted to the performing arts. And if past experience is any guide, they will gather for impromptu pickup recitals under the trees. In addition, there will be a traditional religious music pro gram on Sunday, running for three hours and including In dian ritual, black and country traditional songs, transplanted ethnic music to modern gospel and country hymns. Workshop Areas One of five workshop areas will be devoted to native peo ples, where there will be darri es and craft demonstrations by Eskimos, Makah, Haida-Cape Fox and, from New York, Onondaga Indians. They will demonstrate such things as wood and ivory carving, sil versmithing, skin sewing, rug and basket weaving and bead work. Another area is set aside for demonstrations for building and repair techniques of such folk instruments as guitars, mando lins, dulcimers, thumb pianos and fretless banjos. The festival is produced by the National Folk Festival As sociation and is sponsored in part by the National Park Serv ice and the National Endow ment for the Arts. Dancing Groups There will be ethnic and Square dancing by such groups as the French-Canadian troupe, Less Danseurs du St. Laurent, Quebec; the Blue Ridge Moun tain Dancers of Hendersonville, N.C.; the Arthur Hall Afro- American Dance Ensemble of Philadelphia, The Ambrose Thibodeaux Ca jun band from Eunice, La., will be on hand, as will the Moving Star Hall singers from Johns Island, S.C., who do spirituals, shouts, ring games and play party songs with strong African influences. Traditional American blues will be represented by Roose velt Sykes and Henry Towns end, both of the St. Louis school; David ‘Honeyboy” Ed wards, a native of Shaw, Miss.; Carl Martin, Ted Bogan and Edward and Tom Armstrong, of the Knoxville area. Younger performers include Taj Mahal, a New York City native, and John Prine, who grew up in the Kentucky min ing country and who records his many compositions for At lantic records.