J.C. Turner, the white-haired man known as "Mr. Labor" in the District of Columbia, no longer sits on the board that operates RFK Stadium and the D.C. Armory.

In Turner's place sits Stuart J. Long, a young realtor who owns the Hawk and Dove restaurant on Capitol Hill and who helped finance Marion Barry's long-shot campaign for mayor.

The Rev. Lloyd Casson, canon of Washington Cathedral, used to sit among the four lawyers, one judge and one physician on the D.C. Commission on Judicial Tenures and Disabilities, which has the power to remove or retain Superior Court judges.

Now Casson has voluntarily left the panel. His replacement is to be Bernice Just, who has spent much of the past decade as a community worker looking at criminal justice from the bottom up and much of last winter working on Barry's transition team.

At one time, former city administrator Julian R. Dugas ran the city's Alcoholic Beverage Control Board, sitting as its chairman and assisted by his hand-picked licenses director, James W. Hill, as a second board member, and a staff director who was also Dugas' close ally.

Now Barry has that same control and more. His hand-picked acting licenses chief, Robert Lewis, his excutive secretary; Dwight S. Cropp, and Larry C. Williams, a lawyer and lobbyist who was one of Barry's earliest supporters, occupy the three seats on the board that regulates liquor licenses in the city.

Slowly, meticulously and with pointed concern for race, sex, neighborhood and, in some instances, political past, Barry has begun to lace his influence through the web of more than 100 boards and commissions that shape city policy. He has appointed nearly 200 persons to these bodies during his first six months in office.

Ivanhoe Donaldson, the mayor's general assistant and closest political adviser, insists that politics have not been the aim of the appointments, which have been made from a list of applicants estimated at more than 1,000.

"They're not political cronies by any stretch of the imagination," said Donaldson, who examines the lists of possible appointees before they reach the mayor's desk. "It's an appropriate way to put your stamp on the government. That's how you determine the policy and the social direction you believe in. But it's not an appropriate way to build a political organization."

The mayor agrees. "Politics is the last consideration," Barry volunteered to a reporter.

Betty King, one of two special assistants to the mayor whose job it is to gather names for the appointments and monitor vacancies on the 115 panels, was of a different mind.

"Every appointment that's made is a political act," King said. "It would be naive to suggest that there's nothing political about political appointments."

In a city where elected politics is just beginning to bloom, the appointments are a source of valuable patronage for the mayor.

In a general sense, the new mayor has tried to select more blacks, women and persons from outside Wards 3 and 4, and upper income black and white sections of the city, which in the past accounted for most of the appointees.

Wards 3 and 4 still have the largest numbers of appointees, according to figures compiled by the Barry staff. Of the first 165 Barry appointees, 25 came from Ward 3 and 24 from Ward 4, with the next highest number, 17, coming from Ward 2. Most of the other wards were nearly evenly represented among the remainder - except for often neglected Ward 8 in Anacostia, which had only seven appointees. Ten persons selected were not District residents.

There were 100 blacks, 50 whites, 13 Hispanos and 2 Asians. Barry appointed 94 men and 71 women.

Donaldson estimated that 80 percent of those chosen have no political connection to Barry. Yet, some of the choicest positions went to Barry allies.

"What is he supposed to do, not appoint someone just because they supported him?" Donaldson said when asked about that observation.

For example, realtor Jeffrey N. Cohen, an early supporter of Barry, was appointed to the D.C. General Hospital Commission, which runs the city's publicly financed hospital. Two other Barry supporters, architect Robert Nash and Foggy Bottom community activist Ann Loikow, were chosen for the National Capital Planning Commission.

The D.C. Commission on the Arts and Humanities, which dispenses more than $300,000 annually in grants, is peppered with Barry supporters. They include the new chairman, Peggy Cooper, and members John Kinard, who headed a Barry transition task force; Ted Gay, who ran John Ray's campaign for City Council, which Barry actively endorsed, and Heidi Lehrman Berry, whose husband Max was Barry's campaign treasurer. The principal staff person for the commission is Mildred Bautista, a key aide on Barry's transition team staff and the wife of Assistant City Administrator Colin F. S. Walters.

The board and commission appointments also offer the new mayor a chance to broaden his political base through the appointment of persons who were not among the odd-lot coalition of Democratic irregulars who made Barry a slim minority victor in the party's close three-way primary election.

For example, Charlotte Chapman, who was a stalwart supporter of Washington during the campaign, has been retained as chairman of the Minority Business Opportunity Commission and reappointed as one of the city's five representatives on the board of Group Hospitalization Inc.

Realtor H. R. Crawford, who opposed Barry's choice of Ray to replace Barry on the City Cuncil, has nevertheless been appointed to the Board of Equalization and Review, which hears appeals on property assessments.

According to some Barry aides Crawford and Chapman offer Barry potential support in some sectors of middle class black Washington that previously scoffed at his candidacy.

"We haven't politicized anything around here since Jan. 2," Donaldson insisted. "I don't approach the boards and commissions politically."

This is the way he sees it: "If you bring people on board and you do a good job and they do a good job, they'll support you," he said confidently. "To make it all political would be unnecessary."