TreeCentric is a 'green web hosting provider' that offers shared and dedicated hosting plans.
The shared hosting plan is fairly comprehensive. The pricing is reasonable. The featureset is sufficient for hosting typical PHP based web applications such as blogging or wiki engines.
Their dedicated servers are configured similarly to the shared servers with the same sort of software etc. You do not get root access to the server raising the question of what's the point to getting a dedicated server without root access?
They claim status as a 'green web hosting provider' through purchasing renewable energy credits. They do not state where the REC's come from. However they do state to be Green-E certified meaning their power provider has been through the green-e auditing process and satisfies Green-E that the power is renewable.