Trading surged despite a cut in supply, primary EUAs were priced at €5.55 ($7.56) per tonne of CO, (tCOj). Demand for voluntary offsets dropped in 2013, along with average prices (to $4.90/tCO, marketwide).This can be partly explained by the introduction of California state's cap-and-trade regulation, which requires all covered entities to register through the Air Resources Board, which is a compliance-based market (thus moving a large volume of trade from voluntary to compliance markets). Continued efforts to assert the credentials of wood as an environmentally preferable material are essential, as are research and other efforts to address potential policy shortcomings.