Sustained Yield Forest Products   Despite advances in plastic, metal, masonry and wood chip building materials, wood will continue to occupy a major role in residential and light commercial construction. Unfortunately, this is an era of a failure of federal agencies to foster policies of ecological stewardship of our forests.   However, we are also experiencing a burgeoning small industry of sustained yield forest management and harvesting. New ANSI standards and private wood certification programs are in place that can verify if wood is harvested from practices that ensure forest ecosystem diversity, water runoff retention, and forest soil protection. New forestry practices are being developed, old ones are being revived, and tested timber harvesting methods from Europe are being imported to replace our short sighted, ugly and destructive practice of clear cutting and deforestation.   We are also discovering the beauty, utility and economy of reusing wood from existing stuctures. Demolition and resurfacing techniques are being utilized that enable us to reuse and recycle structural members, flooring and even moulding runs.   Specifying and obtaining these woods and wood products requires networking and preplanning. We cannot, as yet, run down to a local lumber yard and expect to find dimensioned framing lumber certified from sustained yield forest practices. Below are sources that will help to ensure that at least a majority of a structure's wood products have not been taken at the expense of a forest ecosystem.   There are serveral organizations that certify that wood comes from  sustained yield sources.  However, the standards of  the Forest Stewardship Council or FSC are universal.   If a certifier of  wood is not a member of FSC, the standards they apply may be too low to qualify as sustainable.   Good Wood Alliance is the most comprehensive clearinghouse of information about various woods, wood sources and wood certification. Sustained yield certification progarms such as Rainforest Alliance's "Smart Wood" and SGS Forestry Certification are covered.