Flow rate and fixation of ACQ-D preservative in poplar living tree after injection

To address the concerns regarding the groundwater contamination caused by the leachate from traditional alkaline copper quaternary (ACQ) pressure-treated wood, this study used a method of injecting preservative to living tree as it grows. The fixation and distribution of the preservative at different heights of the tree were examined using the software Image-Pro Plus and by scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. It was found that the preservative flow rate in living trees was significantly affected by the solar radiation intensity and air temperature, whereby solar radiation played a more significant role. The leaching test results indicated that, compared with pressure-treated samples, the ACQ-D leaching rate of the injection-treated samples was reduced. The preservative was mainly distributed in vessels and fibers. The increase in contents of carbon elements C1 and C3 indicated that the preservative was stably fixed in trees. It was also revealed that the fixation sites of copper were mainly hemicellulose and lignin.