There's a new way to enjoy the outdoors in upstate New York. Composer Robert Morris is showing us the way through his own artistic genre, which amounts to a new form of recreation: park-music.

Morris, professor and chair of the Eastman School's Composition Department, composed for the outdoors before. Eastman's student-run New Music ensemble, Ossia, performed his first outdoor work, Playing Outside, in Webster Park in 2001.

But you can never get enough of a good thing. So, in a beautiful pine grove near Webster Park's Cattaraugus cabin, Ossia will perform again. This time it's the world premiere of Morris's second outdoor work: Coming Down to Earth.

Judging from the attendance, the applause, and the grapevine, the audience and the composer of Playing Outside seemed to agree: Webster Park provides an ideal environment for listening to New Music. In some ways it beats conventional classical music venues.

"The performance of Playing Outside," says Morris, "confirmed that one does not need to put music in a concert hall for it to have resonance and reverberation. Trees provide a beautiful reflective surface and fields carry sound far and wide."

The open air opens minds and ears too. Music, such as Morris's, that expands the boundaries of convention, often presents a challenge to audiences. Morris finds, however, when that same music moves from the concert stage to the outdoors, audiences tend to enjoy it much more.

"I believe this happens," says Morris, "because when my music is performed in the midst of natural surroundings, it becomes obvious that it is inspired by and reflects my love of natural processes, textures, and sounds."

Sure, nature is fertile ground for the creative impulse, but actually performing a concert in nature opens a whole ecological can of worms: What's nature's role? Are the animals part of the audience, or part of the performance? What about the trees and plants, the streams and brooks?

Theatrical possibilities abound: "How will the birds and other creatures in the forest respond to this uninvited musical performance in their habitat?" wonders pianist, composer, and co-producer of the event, Marcus Macauley. "Will they interact with the electronic bird calls, or with the high licks in the flute, oboe, and violin, contributing their own unwritten part to the score?... Will [the animals] watch in silence, bewildered? Curious? Captivated? Or will they flee the area, frightened out of their wits?"

If animals could read music, indeed they might get frightened. The score of Coming Down to Earth looks utterly strange --- more like experimental visual art, astrological charts, or imaginary biochemical recipes. One page looks like a pebbly landscape, another looks like a pictorial invitation to the afterworld as inscribed on some prehistoric tomb.

Yet the seemingly unnatural look of the score grows naturally out of Morris's purpose: to harmonize music with nature. "Coming Down to Earth is not concert music per se," says Morris, "but something like ambient music, where the music blends into and comments musically on the sounds and sights of the natural location in which it is performed."

"There are no melodies, phrases, or chords in the woods, just textures and single sounds, sometimes groups of sounds. So how can my music 'harmonize' with the sounds of the woods, rather than drown them out, or impose others? And not to imitate, either."

Part of the answer is to have the musicians improvise, in various ways. In one section, called "Clamor," the musicians improvise somewhat freely. Yet the score guides them, producing a cloud of sound in which a just few pitches shine out like headlights in the fog.

In some styles, such as jazz, improvisation also blurs the boundaries between composer and performer, so that the improvisers assert their own creative imperatives. That's not the way of the woods though. On the contrary, for optimum effect, the improvisers should "keep the ego out of it," insists composer and Eastman doctoral student Aaron Travers, who plays keyboard in Coming Down to Earth.

Like watercolor painting, which often lets colors bleed together, so too does Morris's guided communal improvisation, "so that melodies and textures have a kind of blurred sound," says Travers.

Then there's the butterfly effect: nature blurs sound and silence. This alters our experience of something not obviously related: time. "The rhythm of outdoors is usually slower than the social rhythms of music in cultural settings, but sometimes faster too, as with birds and insects," Morris says. "It [the outdoors] is a relaxed rhythm with beginnings and endings not clearly defined, often overlapping. Sound and silence share the sonic space."

Though Coming Down to Earth bustles like boisterous birds, moment to moment, a deeper harmonic evolution drives it, at a geological pace. As a botanist might describe the blossoming of a flower, stage by stage, Morris explains: "In Coming Down to Earth, there are 50 sections, each lasting a minute, each representing one of the 50 basic harmonies of six tones.

"These harmonies slowly change over the piece. They are not often presented as simple chords however, but as component parts of textures and the basis of melodic movement. This slow evolution is like the passage of the day, moving almost imperceptibly from mood to mood."

Morris's chain of harmonies has its own genetic evolution: each harmony in the succession inherits exactly five pitches from its predecessor and contributes one new pitch of its own. It then passes on this new pitch, together with four of its five inherited pitches, to its successor. This harmonic reproductive lifecycle continues for 50 generations, each lasting one minute. Each generation --- each harmony --- is unique, never to be repeated. The 50 harmonies represent every possible harmony of six tones.

The chain of harmonies is almost mystical in its confluence. All possible six-note harmonies are represented, none more than once. Each is connected to two others through inheritance. The fact that such a chain of harmonies even exists was not known until Morris imagined it, and then had to write an elaborate computer program to generate it, and prove its existence in the process. That was no mean feat.

Metaphysics and computer science aside, it's the human audience that completes Morris's grand harmony. So his Coming Down to Earth reaches out to harmonize its audience with its performers by blending the space that usually separates them in the concert hall. The musicians will place themselves inside and around the audience --- nature's own "surround sound."

"I'm looking forward to seeing how the audience will play into the performance," says Gretchen Snedeke, a horn player and co-producer of the event. "In improvisatory works of this nature the behaviors of the audience always have a huge effect on the end product. I would encourage all audience members to recognize the importance of their role and to embrace it."

Ossia will perform Coming Down to Earth by Robert Morris on Sunday, October 3, at 1, 3, and 5 pm in Webster Park. (Raindate: Sunday, October 10) It's recommended you arrive 20 minutes early to allow for parking and walking into the park; bring something to sit on. www.esm.rochester.edu/rdm/cdte/cdte.html. 274-1100. Free.