There are a number of descriptors, both positive and negative, that spring to mind when you think of Philly, but “green” is not one of them. Mayor Michael Nutter wants to change this, as indicated by his announcement today of a plan to make Philadelphia the greenest city in American within the next six years. The plan, called “Greenworks Philadelphia,” sets out 15 goals that the city hopes to reach by 2015, which would be the last year of a Nutter second term.

The plan, developed by staffers in the Mayor’s Office of Sustainability, is an ambitious one, consisting of goals relating not only to the local environment, but to the economy, civic engagement and equality. Officials say they’re hopeful that they can use stimulus money to meet some of the goals, which include large-scale visions, like lowering city government energy consumption by 30 percent, reducing greenhouse gas emissions by 20 percent and diverting 70 percent of waste from landfills, to more cosmetic — but no less important — changes, like providing park and recreation resources within 10 minutes of 75 percent of residents and planting 300,000 trees.

Even if parts of the plan remain to be worked out, like just how the city will clean up its air and how it will work with the state government to deal with problems outside city limits, it’s heartening that Nutter is putting forth such a bold green agenda during a season of cutbacks and compromises. Philly may lack the green reputation of cities like Portland, but Nutter’s plan is heartening since it seems to understand that a plan for sustainability must address the growth of the urban economy and urban equality — and not just a whole bunch of trees.