Chinese fir (Cunninghamia lanceolata Hook.) and Mongolian Scots pine (Pinus sylvestris Linn. var. mongolica Litv.) sapwood were treated with alkaline copper quat type D (ACQ-D) solutions at two concentration levels (0.5 and 1.1%) followed by three posttreatments: oven-drying, conditioning in a humidity chamber, or exposed to boiling water. The effects of treatment on copper leaching from ACQ-D-treated wood were investigated by performing tests according to AWPA E11-06. Analysis of chemical composition and pH values were determined to evaluate the effects of wood species on copper leaching. The results showed that copper leaching from ACQ-D-treated Mongolian Scots pine without posttreatment was lower than that of treated Chinese fir. However, after posttreatment, more copper leaching was observed from ACQ-D-treated Mongolian Scots pine than Chinese fir. For example, after conditioning posttreatment, the percentage of copper leached from 1.1% ACQ-D-treated Chinese fir decreased 58.6 to 1.8%, while for Mongolian Scots pine, it decreased 49.5 to 19.4%. The difference was considered to be related to different chemical compositions and pH levels
