The time to stabilization or equalization of the copper component of ACQ-D was highly dependent on treating solution concentration (preservative retention) and post treatment temperature. Stabilization was rapid for low preservative retentions but extended times were needed for wood treated with higher concentration solutions. The extent of stabilization was also concentration dependent with a higher percentage of copper fixed with lower retention treatments. Increasing the temperature of the treated wood from 22°C to 50°C reduced the stabilization time by up to ten times depending on the ACQ retention and the wood species. There was little species effect for low extractive content red pine (Pinus resinosa), jack pine (Pinus banksiana), white spruce (Picea glauca), balsam fir (Abies balsamea) and trembling aspen (Populus tremuloides). Neither was there a significant difference in the stabilization rates of jack pine sapwood and heartwood. However, Douglas-fir (Pseudotsuga menziesii) stabilized at a greater rate and to a higher degree than the other species with heartwood reacting faster and more completely than sapwood. This is likely attributed to the high reactivity of copper at high pH with phenolic extractives in Douglas-fir.

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