The underlying spirit of “A Forest Unfolding,” the nine-movement cantata that opened the final concert of this year’s Portland Chamber Music Festival, on Saturday evening at Hannaford Hall, is captured most clearly in the text of its last movement, by Richard Powers.

A forest, Powers writes, is a single entity, its trees “networked together underground by countless thousand miles of living threads,” through which they communicate, heal and nourish each other. “There are no individuals,” Powers continues. “There aren’t even separate species. Everything in the forest is the forest.”

It’s a lovely notion that has been gaining scientific support, but the idea of trees as a communicating community has been a part of contemporary fiction, going back to “The Lord of the Rings,” “The Wizard of Oz” and “Day of the Triffids.”

In a way, “A Forest Unfolding” uses this idea as a model for its own design: It is a collaboration by four composers (David Kirkland Garner, Stephen Jaffe, Eric Moe and Melinda Wagner), who set by selections by six authors and poets. Add the nine performers in the ensemble to the process, not to mention the involvement of two chamber music organizations – the festival and Electric Earth Concerts, in Peterborough, New Hampshire, which commissioned the piece and gave its premiere on Aug. 12 – and you have an expansive yet cozy little artistic eco-system.

The composers contributed individual movements, so their individual voices came through clearly; but since they are stylistically like-minded enough to have forged a common, largely neo-Classical idiom, the movements flow together smoothly. Whether you regard the work’s philosophical underpinnings as scientific or fanciful, the music is appealing, even seductive, at times, not least because the composers fully embraced the imagery of the texts.

Moe’s single contribution, the opening “Native Trees,” illuminates W.S. Merwin’s poem with a graceful, subdued melody against a backdrop of tightly intertwined string, piano and wind lines that evoke the image of an interconnected root system, like the one Powers describes at the end of the work. Mezzo-soprano Tony Arnold brought a purposefully hazy timbre to Moe’s piece.

The second movement brings God into the proceedings, by way of a passage from the Book of Job (from 38:2 to 38:27, in Stephen Mitchell’s modern translation) – a better, more evocative choice than the overused Joyce Kilmer poem. Powers read the text to spare, pointillistic music by Garner, which gives way to Jaffe’s “Eternal Rhythm,” a sweetly melodic instrumental interlude. Jaffe provided two such pieces; the other, the lively, dancelike “Variation-Deciso,” leads into the atmospheric closing movement, Powers’ “Eternal Song,” with music by Garner.

Actually, there is nearly as much reading as singing in this cantata. Arnold read (rather than sang) Anna LaBastille’s “Woodswoman Etude,” a paean to the forest’s permanence and serenity amid the trials of life, for which Garner supplied piano and bass clarinet lines that wrap themselves around the poem like a gossamer web. And Power read a selection from Thoreau’s notebooks, with ensemble punctuation (dominated by flute and clarinet) by Garner.

Baritone Alexander Hurd strained slightly in Jaffe’s chromatic music for Merwin’s “Trees,” but was heard to better effect in Wagner’s inventive transformation of Wendell Berry’s “In a Country Once Forested” into a dialogue for mezzo-soprano and baritone. Hurd and Arnold also wrapped a haunting vocalise around Powers’ text, in the finale.

The movements are all compact, and the musicians – flutist Laura Gilbert and violist Jonathan Bagg (who direct the Electric Earth Concerts), violinist Gabriela Diaz, clarinetist Todd Palmer and pianist Diane Walsh – contributed alert, colorful performances that underscored the pictorial elements of the poetry.

The piece gives listeners plenty to think about, so not surprisingly the second half of the concert was given over to a Romantic masterwork that seemed almost hedonistic, by contrast. Dvorák’s String Quintet in E flat major (Op. 97) does not dabble in philosophy, unless you want to debate whether its nickname, “American,” owes more to the fact that its first movement is built around a theme that hints at the Spirituals that Dvorák encountered during his stay in this country, or simply to the fact that it was composed in Iowa.

Either way, the piece is pure pleasure – melodically rich, harmonically lush, and full of passion. And the ensemble, which included both the festival’s outgoing director, violinist Jennifer Elowitch, and her chosen successor, violist Melissa Reardon, as well as violinist David McCarroll, violist Carol Rodland and cellist Brent Taylor, tapped fully into its warmth and spirit.

Allan Kozinn is a former music critic and culture writer for The New York Times who lives in Portland. He can be contacted at:

allankozinn@gmail.com

Twitter: kozinn