Shifts in soil prokaryotic community structure due to clear-cutting secondary Acacia mangium forests and replacing with Eucalyptus urophylla.

In recent years, many secondary forests have been converted into artificial tree plantations in China to improve forest quality or increase timber production, which may influence soil microorganisms and nutrient cycling. By sequencing and analyzing microbial 16S rRNA genes in the soils of secondary Acacia mangium forests and 5-year-old and 10-year-old Eucalyptus urophylla plantations that were converted from clear-cutting secondary A. mangium forests in South China, we aimed to evaluate the effects of the forest management of clear-cutting and replacing secondary forests on soil prokaryotic communities. Our study found that this type of forest conversion significantly changed the soil prokaryotic community structure at the OTU, family and phylum levels, respectively. The prokaryotic community structure in the 10-year-old E. urophylla plantation were more similar to that in the secondary A. mangium forest than to that in the 5-year-old E. urophylla plantation, suggesting the prokaryotic community in the reforested plantations underwent a gradual restoration. The conversion from secondary A. mangium forests to E. urophylla plantations significantly increased soil prokaryotic abundance from 4.58 × 10 copies g soil to 2.07 × 10 copies g soil, by 4.51 folds. Further analysis shows that prokaryotic abundance was significantly correlated with total phosphorus (p < 0.05). Soil pH, moisture, and total phosphorus significantly influenced the prokaryotic community structure. This study contributes to our understanding of the effects of clear-cutting secondary forests and replacing with a mono-plantation on soil prokaryotic community and provides information for forest management.