A representative sample of black spruce logs from Central Newfoundland was harvested and processed to dressed 2"x4" lumber. Over 400 pieces of lumber were then incised and treated with ACQ preservative in a semi-industrial retort. 9 charges of 20 samples were used to determine treating parameters and 11 charges of 20 pieces were treated using the optimized process. This material was inspected by an independent inspection agency. It has been found that black spruce wood incised to about 9500 incisions per square meter and treated at about 50° C using a 4.5 hour standard full cell process can be treated to the penetration requirements of the AWPA and CSA standards for in-ground application. In regards to retention, all charges fulfilled the requirements for above ground application, but only 4 of 7 charges targeting a 0.40 pcf (6.4kg/m3) in-ground retention met this requirement. It is believed that this was the result of using a standard black spruce wood density for retention calculations, when the wood actually had a much higher density.

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