Even though oriental spruce (Picea orientalis L.), a common species in the East Black Sea Region of Turkey, is used in a wide range of applications, its wood has low permeability. This study investigated the degradation effects of the bioincising process to improve its treatability with wood preservatives on the microstructure of oriental spruce wood. Test samples were previously subjected to bioincising by Physisporinus vitreus fungus, and the bioincised samples were examined under both a light microscope and scanning electron microscope to observe the effects of the bioincising on the anatomical properties. Bordered pits on the longitudinal tracheid radial walls, piceoid-type cross-field pits, ray tracheid bordered pits, and ray tracheid cell walls in the earlywood and latewood regions within a growth ring were particularly subjected to anatomical evaluations. In the study, the degradation intensity in the samples after the bioincising was well correlated with the weight losses occurred. Splits and factures were determined on the tori of bordered pits on the tracheid cell walls while tears and cracks were present on the pit apertures. The results also show that P. vitreus, a Type I and II white rot fungus, may cause a Type I soft rot.