Exhibitions at the David Brower Center (2150 Allston Way, Berkeley) consistently situate artists as the mediators between citizens and economic and environmental issues. The gallery’s third annual juried exhibition, Reimagining Progress, features works that examine the current state of our system of consumption and the potential for more sustainable alternatives. While many of the works are visually gripping, those with applicable concepts underlying their form are the most thought-provoking. Kathryn Kenworth’s “Trade-O-Mat” is a reimagined vending machine that facilitates a bartering economy. A collection of local artworks is featured in five windows, each with a slot below that invites viewers to submit a card with their offer of a service in exchange for the piece. After the artist determines a fair exchange, the two will meet to make the trade. Aviva Knox’s “Authentic Apparel” features white T-shirts made by different companies, each with a tag that outlines the actual circumstances of labor that went into their production. Although Knox uses a shorthand that’s similar to that of normal tags, her tags hang twice as long as the shirts themselves. Collectively, these works impressively push the notions of production and offer an optimistic view of the potential for change.