Preservative treatment of Douglas-fir lumber by the passive impregnation method with copper azole

Laser incised dry (mc = 18%) and green (mc = 33%) Douglas-fir was treated by the passive impregnation method of wood preservation having two different incising densities (7500 and 10 000 holes/m(2)) and dipping times (3 and 12 hours). A 0.68% active ingredient solution of Copper Azole Type B (Tanalith (R) CY) preservative was used in this study. The preservative retention and penetrated area were measured. The total preservative retention varied from 1.61 to 2.68 kg/m(3) depending on the moisture content of wood and conditions of preservation, and in all cases it surpassed the minimum retention requirement for above ground use. The maximum penetrated area for dry lumber (mc = 18%) was 96 and 88% across and along the grain, respectively. For green lumber (mc = 33%), it was 90 and 85% across and along the grain, respectively.