Despite artist Jason Kronenwald’s insistence that he was never much of a gum-chewer, his work — a series of deliciously vulgar portraits of female pop stars — is entirely made of the stuff. His current exhibition at Toronto’s le. Gallery, which bears the politically precarious title Gum Blondes, offers the glamorous visages of such transitory demigoddesses as Britney Spears, Avril Lavigne, Paris Hilton, Jessica Simpson and Sarah Michelle Gellar — with a few icons from the cinematic past, such as Veronica Lake and Jayne Mansfield, thrown in. The works proclaim as their medium "Chewed Bubblegum on plywood sealed with epoxy resin." They have to be sealed with the resin or the gum will eventually dry out, crack or rot.

Because he actually hates chewing gum, and because it takes about 400 sticks of it to make one picture, Kronenwald farms out the chore to apparently never-ending battalions of willing masticators, often public school kids. "They’ll do it for the free gum," the artist tells me genially.

He uses the gum as if it were oil paint ("the mixing takes place in the mouth"), painstakingly pressing the colours — which can turn out to be exceedingly subtle — onto the sheets of plywood in layers, cutting them and shaping them and gradually building up his surprisingly convincing likenesses.

Kronenwald, who has a BFA from Queen’s University, came to bubble gum as a result of his growing disaffection with "elitist" art. "I’ve always been attracted to materials from the world around me," he says. At one point, he was making liquid paper drawings. Since getting serious about the gum works, he has become a media darling. "Good Morning America once flew me to New York for a five-minute item!" he says, as if he finds this kind of attention supremely silly.

What kinds of problems does a gum artist encounter? For one thing, gums get discontinued. "For my blacks and browns, I need a certain kind of licorice gum that is made only every three years, so I have to stockpile it." Right now, Kronenwald is facing another chromatic crisis: "I went to Wal-Mart the other day, where I get most of my gum, and they had dropped the yellow that was an integral part of my palette!" This yellow makes up the golden tresses of his Gum Blondes.

Because this problem seems momentarily insurmountable, we move on to something else. Aren’t women annoyed, I ask, by the phrase "Gum Blonde"? He smiles. "You’d think so," he replies, "but no, I haven’t heard any negative comments from women. I guess they know it’s just tongue-in-cheek."

Trellis at Dyan Marie Projects

$500-$5,700. Until April 8,

1444 Dupont St., Unit 31, Toronto;

416-536-4017

Toronto-based artist Dyan Marie reserves her gallery space for the exhibiting of those all-too-rare emblematic moments in contemporary art where the visual world’s conventional aesthetic and sociological concerns (assorted isms, endless prattle about the body, geopolitical strife) are joined by or entirely give way to a certain hands-on preoccupation with the health and meaning of the environment.

Trellis, her current exhibition, is such an undertaking. This small but powerful and far-reaching show is built on the idea of trellis-as-armature, as a prosthesis for Toronto’s ailing urban environment, which is, as always, undergoing an accelerating tree crisis. Marie’s exhibition, a deft bringing-together of delight and proscription, offers work by five concerned artists: sculptors John McKinnon and Mike Murphy, painter Douglas Walker, landscape architect Janet Rosenberg, and artist/inventor/visionary Napoleon Brousseau, working with his Seed Collective.

Some of the Trellis works are almost literally that. For an increasingly treeless city, McKinnon posits a sort of tree surrogate in the form of a handsome, constructivist trellis made of I-beams. Murphy’s trellis is a hectic combine-work made of wires, plastic sheeting, mirrors, pipe cleaners and blinking lights, all pulling together to make a structure "as temporary and fragile as the plant life they propose to support."

Douglas Walker, whose strange, blue, relentlessly otherworldly paintings are currently on exhibition at Toronto’s Birch Libralato Gallery, is here represented by small, exquisite oil paintings on paper of exotic gazebo-like buildings. They’re depicted in swirls and cartouches of pigment that end up looking like the plants they are designed to support. Janet Rosenberg, in turn, has furnished the show with a single, beautiful giclee print in which the whole teeming city has become, so to speak, its own trellis.

The stars of the show, however — though they’d hate hearing it put that way — are Napoleon Brousseau and the Seed Collective. They’ve devised Seed, a joyful and yet almost demonically strange electronically interactive work: it’s "the first cell-phone driven interactive installation whose purpose is to effect environmental change in the real world." The technology is new, innovative and utterly absorbing (and still under development). What it does, in a nutshell, is let you dial up your own tree with your cellphone, choose its species and size and other variables, and then watch it grow (on a monitor) right before your eyes. Then you can electronically plant it — and, if you keep at it, reforest the entire city.

Sadko Hadzihasanovic

At Paul Petro Contemporary Art

$800-$14,000. Until April 7,

980 Queen St. W., Toronto;

416-979-7874

The paintings making up the section called Playground in Hadzihasanovic’s new exhibition, What the Wonderful World, constitute a suite of pictures about the sort of children who turn up often in the artist’s work: children who are both threatened and threatening. It seems almost reasonable that occluded pop star Michael Jackson should figure prominently in them.

In the gallery upstairs, Hadzihasanovic is showing portraits of wrongfully convicted people from his Places They Have Never Been series. In these affecting works, figures such as Steven Truscott, Robert Baltovich, Yvonne Johnson and others are shown in unlikely settings (beaches, for example). The artist says he is attempting to make "warning signs, icons, out of those faces that suffered unnecessarily" and is thus "taking the responsibility to make modern saints." The result is only half satisfactory: one part redemption, and the other part exploitation.