Long-Term Thinning Does not Significantly Affect Soil Water-Stable Aggregates and Diversity of Bacteria and Fungi in Chinese Fir (Cunninghamia lanceolata) Plantations in Eastern China

Abstract

Soil structure and microbial communities are sensitive to forest disturbance. However, little is known about the long-term effects of forest thinning on water-stable aggregates (WSA), and the community composition and diversity of soil microorganisms. In this study, we investigated soil chemical properties, WSA, and communities of bacteria and fungi in conventionally managed Chinese fir plantation stands and repeatedly thinned plantation stands with medium and high tree densities 18 years after the thinning treatments. The distribution patterns of WSA fractions were similar in the three thinning treatments. The mass proportion was the highest in the macro-aggregates fraction, followed by the clay + silt fraction, and it was the lowest in the micro-aggregates fraction. The soil organic carbon (SOC) concentrations in different WSA fractions decreased with decreasing aggregate size. The WSA fractions, stability, and aggregate-associated carbon were not significantly different among the three treatments 18 years after the thinning treatments. The total nitrogen concentration of the macro-aggregates fraction was significantly higher in the stands thinned intensively than in the conventionally managed stands. The abundance of minor bacteria and fungi species was different, although no significant differences were observed in the overall bacterial and fungal composition and diversity between the three treatments. Our results indicate that, compared with the conventionally managed stands, soil WSA stability and soil microbial communities in repeatedly thinned Chinese fir stands may recover over one rotation of Chinese fir plantation and that this is accompanied by the recovery of stand growth and soil nutrition.

Thinning Partially Mitigates the Impact of Atlantic Forest Replacement by Pine Monocultures on the Soil Microbiome

“…The sensitivity of fungal alpha diversity to forest replacement with pine plantations has also been shown in a subtropical forest of China ( Nie et al, 2012 ). In contrast to our hypothesis, thinning practices did not alleviate the impact on fungal diversity, which is, however, consistent with recent studies ( Cheng et al, 2018 ; Dang et al, 2018 ). The trend to higher bacterial alpha diversity in the thinning plots might be attributed to the increase in bulk density that might protect bacteria from predation ( Hartmann et al, 2014 ).…”

Response of Rhizosphere Bacterial Communities to Near-Natural Forest Management and Tree Species within Chinese Fir Plantations

“…Generally, the dominant phyla of Chinese fir soil bacterial communities are considered to be Acidobacteria , Proteobacteria , and Actinomycetes ( 61 , 62 ). We found, however, that in pure Chinese fir and two mixed forest stand types, the dominant phyla were Proteobacteria and Acidobacteria .…”

Forest density and edge effects on soil microbial communities in deciduous forests across Europe

“…Compared with clear-cutting, thinning (selective harvesting) has been acknowledged as an alternative way in forest management practice due to the benefits in maintaining mature forest functioning as well as the above-and below-ground biodiversity (Gundersen et al, 2006;Lohmus, 2011;Muscolo et al, 2021). As an example, Cheng et al (2018) studied the change of microbial community after a long-term thinning practice (18 years) and found no significant differences in the overall soil microbial composition among different treatments. Besides, the soil microbial community might recover from the disturbances even faster than we expect under reasonably moderate management.…”