This is not about work's based salvation at all within the context of Scripture. We know that the first are necessarily made righteous by God's election of them and the merit of Christ's blood. By merit of this, they are able to do good works, i.e. be trees bearing good fruit.

The latter are remniscient of the other trees, bearing bad fruit.

If this verse is speaking of a works-based salvation, then so is the parable of the trees, which we know is not speaking of works-based salvation, but rather sanctification in the life of a believer.

In this illustration, we're merely seeing the effects of sanctification in the believer's life and how being justified results in being sanctified, and how being sanctified results in being glorified. You can't skip sanctification and go from justification to glorification, and this verse expounds on that I think.

edit: I realize that may not have made sense.... I'll try to remember to write more when i'm not in class.

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Andrew DeShazo, Deacon, Associate Reformed Presbyterian Church, Memphis, TN
"All of us stumble in many ways, but if anyone is never at fault in what he says, then he is mature, able to control his whole body."(James 3:2)