Early effects of crop tree management on undergrowth plant diversity and soil physicochemical properties in a Pinus massoniana plantation

Abstract

Background Soil and understory vegetation are vital components of forest ecosystems. Identifying the interaction of plantation management to vegetation and soil is crucial for developing sustainable plantation ecosystem management strategies. As one of the main measures of close-to-nature management of forest plantation, few studies have paid attention to the effect of crop tree management on the soil properties and understory vegetation. Methods A 36-year-old Pinus massoniana plantation in Huaying city, Sichuan Province was taken as the research object to analyse the changes in undergrowth plant diversity and soil physicochemical properties under three different crop tree densities (100, 150, and 200 N/ha). Results Our results showed that the contents of available phosphorus, organic matter and hydrolysable nitrogen in the topsoil increased significantly after crop tree management, while content of available potassium decreased. The composition of shrub and herb layer was richer, and the dominant species were obviously replaced after crop tree management. The Shannon–Wiener index and Richness index of shrub layer, and the diversity of herb layer increased significantly after crop tree management. Herb layer diversity indexes and Richness index of shrub layer were closely related to soil organic matter, available phosphorus, hydrolysable nitrogen, available potassium, soil moisture and bulk density. As the main limiting factors for plant growth, nitrogen, phosphorus and potassium were closely related to plant diversity and to the distribution of the dominant species. At the initial stage of crop tree management, each treatment significantly improved the soil physicochemical properties and plant diversity of Pinus massoniana plantation, and the comprehensive evaluation was 200 N/ha >100 N/ha >150 N/ha >CK. Compared with other treatments, 200 N/ha had the best effect on improving the undergrowth environment of the Pinus massoniana plantation in the initial stage of crop tree management.

Forest gaps alter the soil bacterial community of weeping cypress plantations by modulating the understory plant diversity

“…Consequently, the understory vegetation receives abundant growth space, water, and heat, which is beneficial for nutrient and biomass accumulation by plants by making complete use of all kinds of resources (Márialigeti , 2016). The TN content is known to be the main limiting factor for plant growth and is closely related to the understory plant diversity (Lucasborja and Delgadobaquerizo, 2019;Lyu et al, 2021b), which was also observed in this study (Figure 1). We observed that the understory plant diversity was significantly affected by the available nutrients and TN content.…”

“…A plausible reason could be that the soil environment of small gaps responds more quickly to interference in the forest than medium gaps, and small gaps are more conducive to the accumulation of soil phosphorus and increased plant diversity in the herb layer. As plants directly use inorganic phosphorus, phosphorus is a limiting factor for plant growth (Lyu et al, 2021b), which requires the hydrolysis of organophosphorus compounds by bacterial and fungal phosphatases prior to absorption by plants (George et al, 2002). Muscolo et al (2007) reported that phosphatase activity gradually decreases in plots with medium or large gaps, which is consistent with the reduction in the phosphorus content.…”

Effect of poplar ecological retreat project on soil bacterial community structure in Dongting Lake wetland

“…Previous studies have shown that, compared with poplar, reed has a higher underground biomass development, more prosperous root system, and is more difficult to decompose than poplar litter ( Monti and Zatta, 2009 ; Chimento and Amaducci, 2015 ), which makes more biological residues in the root system of reed and resulting in higher SOM. Moreover, understory plants were significantly correlated with the SOM ( Abebe et al, 2020 ), the lack of understory plants would lead to low carbon storage in plantations ( Lyu et al, 2021 ). The litter accumulated under the poplar plantation will cause direct physical obstacles to the germination of understory plants ( Ellsworth et al, 2004 ; Yu et al, 2021a ), and will also directly or indirectly affect the survival and renewal of understory plants by affecting the microenvironment such as light, temperature, and humidity, thereby reducing the SOM content ( Graae and Heskjær, 1997 ; Esteso-Martínez and Gil-Pelegrín, 2004 ; Bo et al, 2018 ).…”

Response of Soil Fungal-Community Structure to Crop-Tree Thinning in Pinus massoniana Plantation

“…The P. massoniana plantation comprises a single tree layer; the shrub layer is primarily composed of Mallotus barbatus (Wall. ), Quercus serrata Thunb, and Cinnamomum camphora; and the herb layer is predominantly covered with ferns [7].…”

“…Crop-tree thinning, a specialized method, achieves this by increasing the proportion of high-quality trees (crop trees) while removing similar-sized trees (e.g., low-forked and undesirable forms) that have limited economic value and lack a competitive position [5]. Although many studies have explored the impact of crop-tree thinning on stand growth structure [6] and plant diversity [7] in forest plantations, they often overlook the interaction of the aboveground vegetation community and the underground microbial community. Understanding this relationship is crucial in comprehending the transformation of inefficient plantations and the consequent effects on ecosystem restoration through crop-tree thinning.…”