Effects of Thinning on Soil Organic Carbon Fractions and Soil Properties in Cunninghamia lanceolata Stands in Eastern China

Abstract

Soil organic carbon (SOC) fractions, along with soil properties, are greatly affected by forest management. In this study, three thinning treatments: control (conventional management mode), moderate thinning intensity and heavy thinning intensity, were applied in Chinese fir (Cunninghamia lanceolata) plantations in eastern China. The dissolved organic carbon (DOC), soil light fraction organic carbon (LFOC) and heavy fraction organic carbon (HFOC), total SOC, DOC/SOC and LFOC/HFOC were not affected by thinning treatments. In the heavy thinning treatment, soil bulk density decreased, and soil water holding capacity and porosity increased in the topsoil layers (0-10 cm and 10-20 cm). Total nitrogen, hydrolysable nitrogen, and zinc concentrations increased in the topsoil layers (0-20 cm) in the heavy thinning treatment compared to the control treatment, while the available potassium concentration reduced. The moderate thinning treatment had little effect on the soil physical and chemical properties. Moreover, the variation of SOC fractions was strongly correlated to soil physical and chemical properties. These results suggest that thinning has little effect on the total SOC and its fractions in one rotation of Chinese fir tree in eastern China. In contrast, however, results also suggest that thinning has a positive effect on soil quality, to a certain extent.

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

“…Fungi can produce various extracellular enzymes to perforate plant cell walls, and they are assumed to be better decomposers of recalcitrant organic matter than bacteria [70]. In the study site, the proportion of recalcitrant organic carbon varied from 79.8% to 84.5% in the three treatments 15 years after thinning [14]. This might partially explain the relatively higher variation in the fungal community than in the bacterial community post-thinning.…”

Patterns of Biomass, Carbon, and Soil Properties in Masson pine (Pinus massoniana Lamb) Plantations with Different Stand Ages and Management Practices

“…Soil pH, total nitrogen (TN), alkaline nitrogen solution (AN), organic matter (OM), total phosphorus (TP), and available phosphorus (AP) were determined. A cytometer was used to measure soil pH, the Walkley-Black K 2 Cr 2 O 7 -H 2 SO 4 wet oxidation method was used to measure soil OM [41], the Kjeldahl method was used to measure TN content, the HClO 4 -H 2 SO 4 colorimetric method was used to measure TP, and acid solution-molybdenum antimony resistance was used to measure TP; the diffusion method was used to measure hydrolyzed nitrogen [42]. To investigate soil physical properties, intact soil cores were collected at three sites in each subplot from each soil layer using a 100 cm 3 steel cylinder.…”

Which Selective Logging Intensity is Most Suitable for the Maintenance of Soil Properties and the Promotion of Natural Regeneration in Highly Continental Scots Pine Forests?–Results 19 Years after Harvest Operations in Mongolia

“…But there are also studies in which thinning had little effects on soil chemical properties [86] or even increased nitrogen. The latter was found, for example, by Cheng et al [37] in Chinese fir stands in eastern China, which they attributed to increased decomposition after the harvest event.…”

“…However, not all thinning and harvest studies conclude that thinning always has an adverse impact on physical soil properties. Soil organic matter or soil organic carbon, respectively, were not affected [37] or even increased under moderate thinning [69]. Obviously, site conditions (soil, climate etc.)…”

“…Three research plots measuring 20 × 20 m (0.04 ha; see [36,37]) were established in each treatment parcel. This made a total of fifteen research plots.…”