Relative abundance of total genomic DNAs extracted from composted yellow poplar chips, and microbial rDNAs by PCR using primers in Table 2. Samples were collected in composting time at 3, 6, 9, 15, 18, 24, and 27 weeks. (A) Amount of total genomic DNAs above the baseline genomic DNAs in compost at 1 week which was 32.7 ± 2.6 μg/g FW compost (FW: fresh weight). (B) Relative level of bacterial, archaeal and fungal rDNAs. 16 s rDNA was used in bacteria and archaea, and 5.8 s and ITS2 rDNA were used in fungi. The bacterial rDNA abundance at 3 weeks was set as 1- fold; archaeal and fungal rDNA relative level was adjusted to bacterial rDNA abundance at 3 weeks. The insert in (B) shows the archaeal rDNA profiling with a fine scale for the relative levels of archaeal rDNA. Note the bacteria-dominant stage at 9 weeks, whereas the fungi-dominant and overall peak stage occurs at 18 weeks. (C) Relative levels of Trichoderma spp. ITS rDNA. Error bars indicate the standard errors of the mean (S.E. ± mean) for the three replicates.