Soil Bacterial Community Composition in Cryptomeria japonica Plantation at Different Times after Clear-Cutting

To understand the mechanism of carbon release from the soil after clear-cutting, it is first necessary to understand the soil microbes, which are the decomposers of organic matter. The aim of this study was to obtain knowledge on the composition of the soil bacterial community in a Cryptomeria japonica plantation at different times after clear-cutting. We established three clear-cutting plots—CC1, CC2, and CC3—in March 2013, May 2017, and December 2017, respectively, and one unlogged plot (Control) in March 2013 in a 35–39-year-old C. japonica plantation in eastern Japan. We collected the soil in May and September 2018 and examined the soil bacterial community compositions of the plots at 5–9, 12–16, and 62–66 months after clear-cutting. The soil bacterial community composition at the phylum level showed a small difference between plots for CC1, CC2, CC3, and the Control. On the other hand, most of the taxa showed similar compositional ratios in the four plots, but some taxa, such as Proteobacteria and Acidobacteria, showed differences. Proteobacteria appeared more frequently in CC1, CC2, and CC3 than in the Control, indicating a longer period of high soil temperature due to clear-cutting. The frequency of Acidobacteria was significantly lower in CC1 and CC2 than in CC3 and the Control, which might be due to the lack of the organic layer (Ao) after clear-cutting.