Tom and Connie Merriman and Eli Pousson The announcement for "Hidden in Plain Sight / The Forest in the City," an exhibition at the Three Rivers Arts Festival Gallery, illustrates how close the Hays Woods tract above the Monongahela River is to Downtown. Click photo for larger image. "Hidden in Plain Sight / The Forest in the City" Where: Three Rivers Arts Festival Gallery, 937 Liberty Ave. (second floor, ring buzzer for entry, handicap accessible), Downtown. When: Through Oct. 21; 10 a.m. to 5 p.m. Tuesdays to Fridays and noon to 5 p.m. Saturdays. Special event: Hays Woods Community Day -- 10 a.m. to 4 p.m. Saturday. Events include walking tours, artists' workshops and demonstrations, and an evening "Community Conversation" (7 to 8:45 p.m.). All events are free. Information: 412-281-8723, ext. 27, or visit artsfestival.net, or savehayswoods.org.

If I could find a way to include a drum roll -- a loud drum roll -- at the beginning of these remarks, I would do so. It's not because I'm writing about an aspect of Pittsburgh's art scene, but because the exhibition in question is of the utmost significance.

The show's title, " Hidden in Plain Sight / The Forest in the City," alludes to the Hays Woods site -- a large and uneven plateau above Hays and the south bank of the Mon across from Hazelwood.

Here there is a forest growing undisturbed on 635 plus acres elevated above any nearby vantage point (hence, hidden) and flourishing only 3 miles from the Golden Triangle, well within the city's boundaries. This extraordinary site, which could contain fragments of the continent's ancient virgin forest, has only come to our collective consciousness in the past several years.

This has come about through the City Council's approval of a developer's proposal to use these acres as the home of 1) a casino, 2) a race track, 3) an upscale residential neighborhood, and 4) an accompanying commercial and retail center. Items one and two are questionable improvements to the life of the city; items three and four are pure folly. Further development of that kind, in a shrinking community, only pours water from one glass, already half empty, into another glass that will never be more than half full.

In order to provide an open terrain for all this, the site would be de-forested, then strip-mined for the coal remaining under the site, and finally leveled with hilltops bulldozed down into the water-carrying valleys. This would be followed by a huge expenditure to provide the necessary infrastructure -- roads, sewer lines, water, electricity, etc. etc. Who pays for all this?

The show challenges this fate, at the moment sanctioned by Pittsburgh's City Council and the URA, some of whose members appear to have had no knowledge of the site and its riches, accepting the peculiar idea that it was only a brown field site. If only they had taken the little time and trouble to look at it.

Looking at it now is a group of artists who, taken collectively, reject this situation and propose preserving the forest as an invaluable green space of a kind no other American city enjoys.

The show, at the Three Rivers Arts Festival Gallery, is the initiative of Thomas and Connie Merriman, teachers at CMU. Alarmed at the prospect of the loss of so rare and remarkable a resource, they circulated a request to the art community for works that in some way would serve to bring this matter to the public's attention and to raise, if possible, the public's awareness of the inestimable value of the forest.

The Merrimans pose the question as to whether there is a better use for the site than that proposed by developers.

Twenty artists or groups responded to the call, and the show, which is greater than the sum of its parts, offers us their various causes and concerns.

It is not surprising to find artists taking a leading role in a public issue. After all, artists have been instrumental in the formulation and examination of a culture's values, from the sculptor Thutmose, giving form to the vision of the pharaoh Akhenaton some 14 centuries before the Christian Era, right up to Ben Shawn examining social and political faults in America of the mid-20th century.

Locally we need look no further than the history of the reclamation of Nine Mile Run, an achievement, still in progress, in which groups such as CMU's STUDIO for Creative Inquiry played a crucial role. In fact, some of the same artists who have been active in that effort are also present among the exhibitors of the Hays Woods show.

The works in the show cover a considerable range of medium and concern. Most of them address in some way the recognized imperative of green space in the life of any viable present-day city. These expressions can take the form of installations or videos or slides, a stimulating mix of the technologies now available to artists.

There is a small but good representation of Pittsburgh's valuable group of landscape painters, here documenting aspects of the forest. Conspicuous among these is a striking canvas by James Nelson who must have positioned himself on an elevation deep in the forest in order to look across the Mon to Oakland, which seems in this context even more improbable. Perhaps some such prophetic vision might have been granted the young George Washington in his trudging about our hills and valleys.

Several of the most ambitious works graphically remind us of the horrible end of ecological and environmental treasures at the hands of developers. While clearly polemical in their mission, the works are nevertheless documentary and objective.

Wit and satire inform many of the items in the show. Perhaps the most subtle of these are a group of small "landscapes" by Carin Mincemoyer who takes transparent molded plastic packaging forms and installs in them fragments of miniature landscape elements. These tiny constructions, installations seen through the wrong end of a telescope, are bright, engaging and cryptic. Could they allude to the surprise in finding landscapes in unsuspected and unlikely places, i.e., Hays Woods?

The emphasis on preservation and conservation is made more evident by there being only one Utopian scheme in the show, and that, by Angelo Ciotti, leaves the vast part of the forest untouched except for the introduction of a tiny walled community, perhaps modeled on mediaeval Italian hill towns and a distillation of the sprawling hodgepodge proposed by the developer. As seen in a small rendering, the town looks like those elegant, gleaming classical cities that rise in the middle distance of Nicholas Poussin's landscape paintings.

The variety of the response to the show's intention can only be appreciated by a visit.