October 10, 1986

FOR the last 25 years, Dan Smiley, director of research for the Mohonk Preserve just outside New Paltz, N.Y., has observed trees and shrubs in the Shawangunk Range to determine the average date for the peak of fall foliage color changes. His conclusion: Oct. 10. However, the broad mass of color is more muted this year in the range and elsewhere north of metropolitan New York because many individual trees, buffeted by strong winds and heavy rains earlier this week, have already dropped their leaves. ''But there are still beautiful small areas of color in individual trees,'' Mr. Smiley said. Even though there are fewer masses of sugar maple trees, normally the most brilliant of all in their crimson, orange and yel-low, this Columbus Day weekend is the best time to travel north to see the annual fall foliage spectacle. Next weekend, the extravaganza can be seen closer to New York City. By the end of October, the oaks, the last of the trees to change color, will have turned a somber brown, a sign of approaching winter.

President Reagan, saying ''serious problems'' in arms control, human rights and other areas mark the relationship with the Soviet Union, arrived here today for his meeting with Mikhail S. Gorbachev. Climbing off Air Force One at Keflavik Airport after a 5-hour and 20-minute flight from Andrews Air Force Base in Maryland, Mr. Reagan was welcomed by the President of Iceland, Vigdis Finnbogadottir. Mr. Reagan arrived in a chilly drizzle, wearing a raincoat. The temperature hovered around 50 degrees, higher than expected by aides bundled up in top coats.

Most Drug Use Stable A new survey says use of almost all illicit drugs except cocaine either remained stable or fell, though drug abuse was still common. Page A14. Met Win, Tie Playoff Bob Ojeda pitched the Mets to a 5-1 victory over the Astros that evened their series at 1-1, with Game 3 at Shea Stadium tomorrow, Page D19.

Markets Two young executives agreed to pay $630,790 in civil penalties for their part in the Dennis B. Levine insider trading scandal. Ilan K. Reich, a former partner in a law firm, and David S. Brown, a former investment banker, did not admit or deny guilt in their settlement of the civil case with the S.E.C. Mr. Reich also pleaded guilty to criminal charges related to insider trading. Mr. Brown earlier pleaded guilty. [ Page D1. ] I.B.M.'s sagging shares dragged the stock market down. The Dow Jones industrial average closed with a 7.03-point loss, at 1.796.82, giving up some strong early gains. Trading was active. I.B.M., which is to report its third-quarter earnings Monday, was off $5.50, to $122, a 52-week low. [ D5. ]

The former director of the New York City Parking Violations Bureau refused to accept a $5,000-a-month payment from a debt-collection agency that wanted him to stay in his job so that a bribery scheme could continue, according to a tape-recorded conversation played to a Federal jury here today. The tape made it appear that the bureau director, Lester N. Shafran, had arranged ''retainers and deals'' worth $100,000 with a competing collection agency, the Datacom Systems Corporation, before he resigned. The conversation was secretly recorded by Michael Burnett, an informer for the Federal Government, at a lunch at Hisae's Restaurant on Cooper Square in Manhattan last Nov. 26. With Mr. Burnett were Bernard Sandow, the president of Systematic Recovery Services, a collection agency, and Geoffrey G. Lindenauer, the former deputy director of the parking bureau.

ONLY a few years ago, church concerts were in many cases synonymous with choral music and organ recitals. But this has been changing. Today, numerous New York houses of worship have opened their doors to a wide variety of alternative programming, and everybody, no matter his religious beliefs, should be able to find a compelling reason to go to church - and not just on the Sabbath, either. Cultural programs have become frequent features in many of the city's churches and synagogues - whether in the sanctuary itself or in adjacent quarters on the same premises. For example, there will be two concerts of world music at Washington Square Church this weekend. Tonight at 8, Seleshe Damessae will sing Ethiopian songs, John Cephas will play and sing Piedmont blues, and Djimo Kouyate will perform songs of Senegal in a program called ''Blues and Roots: An African Heritage Concert.'' Tomorrow night at 8, Simon Shaheen and the Near East Ensemble will offer a program of Arab music.

Friday GIVING LISZT A LISTEN The pianist Robert Goldsand will perform an all-Liszt program at Alice Tully Hall tonight to commemorate the 100th anniversary of the composer's death. The program will include the B-minor Sonata, ''Au Lac de Wallenstadt,'' ''Au Bord d'une Source,'' ''Dance of the Gnomes,'' ''Tarantella,'' ''Spring'' and the Polonaise in E. The recital begins at 8 P.M. Tickets are $12.50 and $15. Information: 362-1911. A YOUNG DANCER IN DEBUT Sixteen-year-old Darren Gibson will make his New York debut this weekend in the opening solo in Eliot Feld's first ballet, ''Harbinger,'' at the Joyce Theater. Mr. Gibson, a student at Eliot Feld's New Ballet School, made his professional debut in West Germany last summer as a member of the Feld Ballet. Tonight's program, which starts at 8 at 175 Eighth Avenue, at 19th Street, includes ''Harbinger,'' ''Echo,'' ''Adieu'' and ''Straw Hearts.'' Mr. Gibson will perform ''Harbinger'' again on Sunday at 7:30 P.M., when the program also includes ''Echo,'' ''Over the Pavement'' and ''Skara Brae.'' This weekend's performances also include ''The Grand Canon,'' ''Medium: Rare,'' ''Theater'' and ''Skara Brae'' tomorrow at 8 P.M., and ''Straw Hearts,'' ''Theater'' and ''The Jig Is Up'' on Sunday at 2 P.M. Tickets are $25. Information: 242-0800.

What Next for Kalb?For Bernard Kalb, whose resignation as the State Department's chief spokesman took effect yesterday, there's been a ''marvelous banquet of offerings.'' Mr. Kalb - who quit to protest what he called the Reagan Administration's ''disinformation program'' against Col. Muammar el-Qaddafi, the Libyan leader - has already heard from literary agents, promoters of lecture tours, people asking him to write a column and network representatives. Before joining the State Department, Mr. Kalb reported on foreign policy for CBS News and NBC News. Howard Stringer, the acting president of CBS News, says he has approached Mr. Kalb. ''As a man who resigned as a matter of principle,'' Mr. Stringer said, ''he ought to be given consideration at CBS News.'' The Cosmo 'Mom'Cosmopolitan magazine thinks it is keeping up with what's going on. Its November issue will carry a special section devoted to working women who have babies.

An American captured when a plane delivering supplies to rebels was shot down here said today that the supply flights were directly supervised by members of the Central Intelligence Agency in El Salvador. ''Two Cuban naturalized Americans that work for the C.I.A. did most of the coordination for the flights and oversaw all of our housing, transportation, also refueling and some flight plans,'' the prisoner, Eugene Hasenfus, said at a news conference here with Nicaraguan officials seated beside him. Mr. Hasenfus then named the two reported C.I.A. officials and gave the most detailed account so far of rebel supply operations out of El Salvador and Honduras. His statements are being treated as a major political victory by the Nicaraguan Government. Plane in 'Sting' Operation ''I was told we were working out of the El Salvador Air Force base at Ilopango,'' Mr. Hasenfus said. ''We would be flying into Honduras to an air base called Aguacate and there we would load up small arms and ammunition and fly into Nicaragua. There it would be dropped to the contra.''

IN Russian they call it ''zakuska.'' That means a spread of mixed appetizers, and if ever there was a zakuska of a film exhibition, it is the one opening today at the Museum of Modern Art. The series is called ''A Salute to the Soviet Republics'' and will run through Nov. 4. Seventeen films shot in all 15 Soviet republics make abundantly clear the ethnic and cultural variety of that vast land mass sprawling over Eastern Europe and the top of Asia, and containing 280 million souls. Museum movie experts say that never before have Americans had the chance to see the people of the Soviet Union in such diversity on film. Among them are Armenians and Georgians; Uzbeks, Azerbaijanis and Kazakhs; Turkmen, Byelorussians, Ukrainians and Moldavians, as well as the people, 139 million strong, who inhabit the biggest Soviet republic of all - that of Russia.

John A. Zaccaro was charged with attempted extortion and with bribe-seeking in an indictment unsealed yesterday in Queens. The indictment charges that in 1981 Mr. Zaccaro acted ''in concert with'' Donald R. Manes, then the Queens Borough President, and ''attempted to steal'' an unspecified amount of money from a cable-television company seeking a franchise in Queens. Lawyers familiar with the case said the grand jury had received testimony that the amount was $1 million. Mr. Zaccaro, a real-estate and insurance broker, pleaded not guilty at his arraignment and proclaimed his innocence again to reporters outside the courthouse in Kew Gardens. He was joined by his wife, former Representative Geraldine A. Ferraro, who denounced District Attorney John J. Santucci. She accused Mr. Santucci of political motivation in pushing the investigation and declared that her husband had rejected an offer from prosecutors for immunity if he agreed to testify against a longtime friend, Chief Administrative Justice Francis X. Smith of Queens.

The chairman of the Federal Reserve Board, Paul A. Volcker, has dropped his longstanding insistence that any banking legislation passed this year include a provision to ban limited-service banks. In letters sent to Congress this week and released by the Fed today, he said that various emergency provisions dealing with banking should take a higher legislative priority. Limited-service banks do not offer all the services listed in the regulatory definition of a bank and thereby can skirt Federal prohibitions against the mixing of banking and commerce. For five years, Mr. Volcker has argued that these institutions, also called non-bank banks, are a source of potential problems for the financial system since close associations between a banking organization and a commercial parent company could compromise the lending judgment of bank officers.