Life-Cycle Inventory Analysis of Manufacturing Redwood Decking

Abstract

Green building has become increasingly important. Therefore, consumers and builders often take into account the environmental attributes of a building material. This study determined the environmental attributes associated with manufacturing 38-mm × 138-mm (nominal 2 × 6) redwood decking in northern California using the life-cycle inventory method. Primary data collected from four redwood mills represented over 83% of redwood lumber production. The primary data were then weight-averaged on a per-unit basis of one m³ of planed redwood decking (380 oven dry (OD) kg/m³) to calculate material flows and energy use. The cumulative unallocated energy consumption associated with manufacturing 1.0-m³ planed redwood decking from 1.8 m³ of incoming logs was found to be 1,500 MJ/m³ with 14% of the energy provided by burning wood residues. Emission data produced through modeling the production process found that the estimated total biomass and fossil carbon dioxide emissions were 20.6 and 69.7 kg/m³, respectively. Our analysis estimated that 38-mm × 138-mm redwood decking stores 697 kg CO₂-equivalents per m³ of planed redwood decking assuming carbon content of wood of 50%. The amount of carbon stored in redwood decking exceeds the total carbon emissions during manufacturing by a factor of eight. Therefore, low carbon manufacturing emissions and redwood decking’s ability to store carbon when in-use are positive environmental attributes when selecting a decking product.

Citation

Bergman, Richard D.; Han, Han-Sup; Oneil, Elaine; Eastin, Ivan L. 2012. Life-cycle inventory analysis of manufacturing redwood decking. In: Proceedings, 55th international convention of Society of Wood Science and Technology, 2012 August 27-31, Beijing, China.