Treatability Changes of Radiata Pine Heartwood Induced by White-Rot Fungus Trametes versicolor

Abstract

Desired retention and depth into wood are necessary for wood preservatives to provide long-term durability. In general, heartwood of wood is difficult to treat, and bioincising was investigated as a potential technique to improve the treatability of refractory wood and heartwood. In order to study the effects of bioincising treatment with white-rot fungus Trametes versicolor on the pore structure and treatability of radiata pine heartwood, this research conducted tests of mass loss, microscopic structures, pore structure parameters, uptake, and penetration of preservative of radiata pine heartwood specimens incubated by T. versicolor for 4, 8, and 12 weeks. The results showed that the optimal inoculation time of T. versicolor bioincising on radiata pine heartwood was 4 to 8 weeks. At this time, the retention of injected preservatives increased by 5.01%–17.73%, the penetration depth of preservatives increased significantly, and the corresponding mass loss was 3.04%–6.45%. The results of microstructure and pore structure showed that T. versicolor entered the adjacent tracheids via apertures, with less impact on the cell wall, mainly degrading pit membranes and ray parenchyma cells early in the inoculation of radiata pine heartwood. As the structures impeding fluid flow were connected, the porosity of the wood and the range of the main pore size distribution increased significantly, thus increasing the treatability of radiata pine heartwood.