They say that people never value something until it's taken from them. Well, the devotion of the Naumburg family to the cause of classical music has never been in doubt: Its members were instrumental in creating the Naumburg Foundation Awards for young musicians, the classical radio station WQXR-FM, and teh Santa Fe Chamber Music Festival. But in 1989, they came close to losing something dear to their hearts - the Naumburg Bandshell in Central Park, which has hosted concerts since 1923.

Legal action kept the wrecking ball away, concerts continued, and, although the bandshell has not been fully restored to its original Beaux Arts grandeur, it's survived well enough to host the 199th season of the Naumburg Orchestral Concerts, which began Sunday evening with a program conducted by Christoph Campestrini.

American music is the focus of the centennial season, although - predictably - non of the young conductors are American-born. Further concerts are to be led by Carlos Miguel Prieto (including music by Ives, Ginastera, Coplan, Revuiltas, Barber and Bernstein); Gregory Vajda (Stravinsky, Hindemith and Bartok); and Charles Olivieri-Munroe (Ibert, Glass, Dvorak and Husa). All enjoy burgeoning international careers.

The Naumburg Orchestra itself, despite the foundation's association with the young players, is made up of a typical array of seasoned freelancers who bring more than enough professionalism to the task of a summer evening's entertainment. Campestrini is a veteran of the German opera-house system, and he keeps things crisp and bright; the sound system, except for some over-miking of the piano and harp, usually cooperated.

Two jazz-inspired compositions by American immigrants - Milhaud's "La Creation du Monde" and Stravinsky's "Ragtime" - began each half. But the meat of the program came i n two even jazzier American concertos, and it was well served.

Charles Neidich, long a distinguished part of New York's chamber and contemporary-music scenes, soloed in Copland's Clarinet Concerto. He treated the opening slow movement as a pleasant prelude, moving quickly to the fast finale, which he rendered with sinuous phrases and a hard, driving swing. Vadim Gluzman, out front in Berstein's Serenade for Violin and Orchestra, was an exciting discovery. he was once a protoge of Isaac Stern, and he combines his idol's tastefully luxurious manner with flawless intonation and an utterly secure technique.

At the end of the concert, several generations of Naumburgs sang "Happy Birthday" in front of the stage, joined by Gluzman, the orchestra and the contented audience - whose members then strolled away quietly in all directions, twirling glowsticks and enjoying the cool night air