Rapidly Renewable Materials' Complex Calculus
Given such complex questions, it's worthwhile to reconsider whether materials now deemed rapidly renewable are as green as those derived from well-managed forests of fast-growing trees, say some sources. Well-managed forests can be relatively healthy ecosystems, while agricultural fields are essentially clear-cut every year, exposing soils to erosion, and they are often treated with chemicals and irrigated, says Alex Wilson, who heads BuildingGreen, publishers of Environmental Building News and the GreenSpec Directory, and is consulting editor of GreenSource, which like architectural record, is published by McGraw-Hill. Until now, the USGBC has awarded LEED points for wood only if it comes from FSC-certified forests. Recognizing that LEED would make faster inroads in U.S. construction with timber industry support, Wilson advocates a two-tiered system that gives partial credit when wood from well-managed forests that do not meet FSC criteria is used. He also recommends considering many life-cycle attributes when comparing wood and more rapidly renewable materials.
Â
|
Â
The USGBC is evaluating modifications to the LEED credits that pertain to rapidly renewable materials and wood certification. Owens points out that the term "renewable" should be considered in context. "If you're using wood for structural framing in a house that will exist for 100 years, ‘rapidly renewable' might be 50 years, because the resource regenerates in less time than one cycle of its use."