While some Brooklynites are lobbying to get trees removed from their neighborhood, Canadian street artist Poster Child is planting them around the city. There's already a dwarf pine in a long-retired newspaper dispenser on Bedford Avenue, and now he's gone and planted another in a telephone booth in Astoria. Personally, we'd like to see an entire greenhouse in one of the four remaining enclosed booths (as long as no one's using them anymore, that is). Challenge.