Timberland (NYSE: TBL) may have a very earthy, alluring secret weapon to help drive future enthusiasm and sales growth.

In its most recent quarterly conference call, the footwear maker's management discussed the burgeoning popularity of its Earthkeepers product line. Earthkeepers boots are described as part of the company's focus on technological innovation and "big idea" initiatives.

Timberland has a history of executing interesting, environmentally minded initiatives. Take its sustainability "nutrition label" (Green Index) for its products, which launched three years ago, predating the Eco Index recently joined by the likes of Nike (NYSE: NKE), Target (NYSE: TGT), Levi Strauss, Columbia Sportswear (Nasdaq: COLM) and Patagonia.

Timberland's Earthkeepers line is similarly high-minded. The footwear collection, which debuted in 2007, uses organic, renewable, and recycled materials; its Green Rubber outsoles are comprised of 42% recycled rubber. A year ago, Timberland introduced a recyclable Earthkeepers boot.

Earthkeepers may be a nascent part of Timberland's business thus far, but these eco-friendly boots for men, women, and children are one of Timberland's fastest-growing product lines. In the conference call, Timberland CEO Jeffrey Swartz said they're "flying off the shelf" at retail, with a 300% sales increase year over year in all regions. In addition, he asserted that "Earthkeepers demonstrates clearly that we can create value for shareholders while asserting our values."

This initiative complements Timberland's socially responsible theme. Launching new ideas with lofty missions helps it compete with -- and hopefully differentiate itself from -- rival shoe companies such as Deckers (Nasdaq: DECK), Crocs (Nasdaq: CROX), Steve Madden (Nasdaq: SHOO), and Nike.

That said, we'll probably see more eco-friendly and green shoes coming down the runway from rivals. Deckers recently unveiled its own environmentally responsible shoe brand, Simple. In the company's most recent conference call, CEO Angel Martinez said that after having Simple on the back burner for a few years, Deckers is bringing it to the forefront now, to an enthusiastic response from retailers. Clearly, consumers are interested in sustainable shoes, and Timberland can't assume that it'll have this market all to itself.

Timberland's commitment to sustainable values is a major reason why I made it the debut pick for my Rising Stars portfolio. The kind of "big ideas" it pursues could lead to positive changes for the world at large -- and create future growth for long-term shareholders.

Nike and Timberland are Motley Fool Stock Advisor selections. The Fool owns shares of Timberland. Try any of our Foolish newsletter services free for 30 days.

Alyce Lomax does not own shares of any of the companies mentioned. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.