Recently, I have heard a number of people question whether bamboo clothing is truly environmentally-friendly. This National Geographic Green Guide discussion does a great job of addressing this question from both perspectives.
In theory, bamboo is an environmentally-friendly fabric: it grows quickly without a lot of pesticides and water, and can regenerate itself. In practice, however, the processes for turning bamboo into clothing – particularly in large volumes – is less conducive to the environment. The article’s bottom line is that bamboo is still a better alternative to non-organic cotton and unnatural fibers.