Green Building Materials   Every material marketed to the construction industry today will likely have some kind of "Friendly to the Environment" or "Clean and Green" message attached. It would seem that overnight everything is now sustainable and earth friendly.   Occasionally a material, building supplier or manufacturer is making significant advances in becoming environmentally responsible. How to sort these material choices, suppliers and manufacturers out is a mission of this site.   It is the intent here to direct attention to those sources that display positive and substantiated efforts in the selection of high quality materials or building systems that reflect our 5 Principles of Environmental Design. The databases and resource sites listed below are good places to start.   HOK Architects has published their in-house Sustainable Design Database. This work, organized in CSI format, is in progress and a real contribution to the development of a systematic Green knowledge base.   The REDI database maintained by Oikos is a place to start in seeking out green materials and systems under the CSI divisions format. Products may not have been systematically reviewed but the breadth of the building industry is covered.   Sustainable Building Source Book published by the City of Austin Green Building Program is full of resources and information about green building practices and materials, especially in the Southwest.   Environmental Building News is the premier professional publication in the United States reviewing and discussing environmentally responsive building materials and techniques. At the ENB site many material reviews from past issues can be found.   Our section on sustained yield building materials covers issues involved with forest products.