Who was the catalyst for a distinctive American musical style? The answer came near the end of the Pacific Symphony’s eighth American Composers Festival: Antonín Dvorák, who, of course, was no American. In his three years in America, the Bohemian composer not only criticised native composers for imitating Europeans but also showed them how to write concert music imbued with indigenous American elements.

Dvorák was not a primary focus of this year’s festival, having supplied grist for a previous one. But he was the starting point for an exploration of music inspired by the American frontier. The haunting Largo from the New World Symphony took on new meaning in a visual presentation involving projections of vast outdoor canvases by the likes of Albert Bierstadt and Frederick Remington. This music was a launch pad for the “simple textures, widely spaced chords and non-directional harmonies” that, as the festival’s artistic adviser Joseph Horowitz informed audiences, are common elements of music evocative of the frontier. Works by, among others, Virgil Thomson, Aaron Copland, Roy Harris and Lou Harrison bore him out, and two composers-in-residence, Stephen Scott and Curt Cacioppo, supplied newer music in similar vein.

The Pacific Symphony’s annual exploration of America’s musical heritage is probably unique and certainly thought-provoking. It brings critical attention to America’s youngest major orchestra (founded in 1978), one that continues to forge its identity in the shadow of the Los Angeles Philharmonic. Until an acclaimed German tour in 2006, the orchestra had hardly left Orange County. But that same year it moved into the gleaming new César Pelli-designed Renée and Henry Segerstrom Concert Hall in Costa Mesa, one of the last halls masterminded by the late acoustician Russell Johnson.

The orchestra’s success in Germany was no coincidence, for its music director, Texas native Carl St Clair, is possibly better known there than at home. Currently general music director of Weimar’s German National Theatre and Staatskapelle (he leads the Ring in July), St Clair takes over Berlin’s Komische Oper this year.

From a taxing and varied festival programme, the late Lou Harrison’s Four Strict Songs, a product of his early emancipation from serialism (1955), emerged as a high point. Choral statements (by the Pacific Chorale) of the composer’s Navajo-inspired texts, set to enthralling pentatonic melodies, had an awesome grandeur, while archaic just intonation and a percussion battery augmented by water bowls and maracas brought arresting qualities to the orchestral support.

Scott can safely be numbered among composers who have devised means of sonic expression that are truly their own. He and the nine other performers of his Bowed Piano Ensemble probe the insides of a piano with implements such as nylon fish line, horse hair on tongue-depressors and guitar picks; in the process they obtain an unexpected array of euphonious results.

Scott’s roots as a Steve Reich-inspired Minimalist ensure that his compositions are far from being simple aggregations of random sounds. Tonality is indeed a possibility, one exploited in “Sun Catcher” from Vikings of the Sunrise, in which industrial-sounding pulsation supports intertwining, long-breathed melodic lines. In Pacific Crossroads, heard in its world premiere, the mini-orchestra generated by the piano interacted with the real one for a whimsical evocation of western figures ranging from the explorer Balboa to the sculptor Richard Serra. For those concerned about the well-being of the participating Steinway, it took about 30 minutes to restore it to its original pristine condition.

Cacioppo’s Crying for Justice (1998), given its professional premiere, touched on the mistreatment of native Americans. Peaceful flute musings are encroached upon by an insistent tune and by powerful unisons en route to a strong but inconclusive close suggesting that the story is not over. Listening material of a more accessible sort was supplied by two movements from Ferde Grofé’s Grand Canyon Suite (1931) – not the hackneyed donkey-clomping of “On the Trail”, but “Sunrise” and “Cloudburst”, in which the piece behaves almost as if it were an American Alpine Symphony. St Clair was alert to opportunities for bringing his orchestra’s capacity for colour and virtuosity to the fore, and it responded handsomely. He and the orchestra also gave a robustly picturesque account of Copland’s Suite from Billy the Kid.

A concert on the campus of Chapman University, in addition to proclaiming Dvorák’s seminal importance by way of pianist Grace Fong’s fluent performance of excerpts from his American Suite, uncovered fascinating works from the early 20th century by Arthur Farwell, who lived for a time in a native American village on Lake Superior and soaked up its musical culture. Artistic adviser Horowitz’s designation of Farwell as “an American Bartók” seemed apt given Fong’s performance of Navajo War Dance No 2, an arresting piece with percussive themes of irregular phrase lengths. She also played his brief Pawnee Horses, which proved even more striking in its a cappella choral version (sung by the Chapman University Choir); with its hocket-like writing, it seemed to dart between modernism and something from the Middle Ages. Cacioppo’s Tuscon Scherzo, a well-constructed work of contrapuntal ingenuity for piano, flute, clarinet, violin and cello, testified to the continuing appeal of “Indianism”.

The concert ended with a screening of the 1936 New Deal documentary The Plow that Broke the Plains, supported by a performance of Thomson’s enduring score by members of the Pacific Symphony and the Chapman Chamber Orchestra, expertly synchronised by the conductor Daniel Alfred Wachs. In spite of the film’s subject of hardship in America’s dustbowl, the hymn tunes, cowboy songs and dances of Thomson’s irrepressible music expressed American resilience and optimism. The latter was surely a subtext of the documentary. And it was underscored by the American Composers Festival itself.