Effects of Thinning on Microbial Community Structure in the Organic Horizon of Chinese Pine Plantations in Badaling, Beijing, China

Abstract

Research Highlights: Moderate thinning can effectively improve forestry production and change the microenvironment of understory vegetation. Background and Objectives: Microbial communities control the decomposition and transformation of forest organic matter; however, the influence of thinning on microbes in the organic horizon remains unclear. Materials and Methods: In this study, we subjected four plots of Chinese pine plantations in Badaling, Beijing to different thinning intensities, including no thinning (T0), low-intensity thinning (T10), medium-intensity thinning (T20), and high-intensity thinning (T50). The changes in chemical properties and microbial community compositions observed in the organic horizon, which comprised undecomposed litter (L layer) and half-decomposed litter (F layer), were analyzed after thinning. Microbial community compositions were evaluated using phospholipid fatty acid (PLFA) methods. Results: The results showed that the abundances of gram-negative bacteria (GN) and total bacteria (B) under the T10 thinning condition were the highest among the four thinning intensities, and the abundance of arbuscular mycorrhizal fungi (AMF) in T20 was higher than under other thinning intensities. The abundance of gram-positive bacteria (GP) and actinobacteria (ACT) in T10 was lower than in both T0 and T50. The abundance of total PLFAs and fungi (FU) was higher in the L layer, whereas the abundance of GP, GN, B, ACT, and AMF was higher in the F layer. Conclusions: Our results demonstrated that the L layer better reflects the influence of thinning on litter. Redundancy analysis (RDA) results indicated that the organic carbon (LOC) , dissolved organic carbon (DOC), and ammonium nitrogen (NH4+-N)contents of litter were primarily responsible for the observed changes in microbial community structure, with LOC alone explaining 62.6% of the total variance among the litter substrate factors selected. Overall, moderate-intensity thinning of Pinus tabulaeformis Carr. plantations created more favorable conditions for microbial communities in the organic horizon.

Hydrological Responses and Flow Pathways in an Acrisol on a Forested Hillslope with a Monsoonal Subtropical Climate

“…2) was the increased evapotranspiration at the start of the growing season, following a temperature increase. However, while evapotranspiration data from Wang (2012), starting in May 2010, showed a substantial evapotranspiration increase from April to May in 2011, evapotranspiration was particularly low in May 2010 and was not likely sufficient to explain the sudden runoff changes from April to May 2010. Because soil water storage showed no difference between April and May (Table II), the only explanation for the high water balance deficit can be the filling up of GDZ with water and partly the leakage of water in deeper layers.…”

“…Studies of Chinese forests at similar latitudes and with similar vegetation indicate that annual actual evapotranspiration can range from 40% to over 70% of annual rainfall, and canopy interception can range from 15% to 30% (Wei et al, 2005). In a parallel study, Wang (2012) conducted a monitoring campaign on evapotranspiration and interception; in this study, throughfall was measured at several spots in the study area, and four representative trees were selected for sap flow measurements. Results from this study confirmed that monthly evapotranspiration varied from 21% (June) to 87% (August) of rainfall in 2010 and could at times even exceed rainfall by up to 300% in months with little rainfall, such as in February 2011.…”

Effects of thinning on tree growth and soil physiochemical properties in Cunninghamia lanceolata plantation

“…On the other hand, in our previous studies, it was found that thinning could promote the development of understory vegetation (Zhao 2021). The improved development of the understory plants after thinning had led to an increasing proportion of rapidly decomposable litter, which could effectively supplement the available nutrient content (for example, SOM, AN and AK) input to the soil (Wang et al 2019;Xu et al 2020;Teste et al 2012;Muscolo et al 2015).…”

Recovery of Soil-Denitrifying Community along a Chronosequence of Sand-Fixation Forest in a Semi-Arid Desertified Grassland

“…Some previous studies indicated that soil N content increased with forest age and significantly differed with forest type [1,7,14]. Therefore, close attention should be paid to the microbes associated to soil N dynamics during the recovery of degraded ecosystems [8,15]. It is possible that soil microbial functional communities involved in N transformation would be significantly altered by the development of sand-fixation forest and restored to its original state.…”

“…These favorable effects increase with plantation age [7]. The development of plantations could also significantly change the soil microbial community [8,9]. However, whether and how the soil microbial community under secondary barren land (shifting sand dune) can be restored via the establishment of plantations is still unknown.…”