Search Results (37)

Bauxite mining causes severe soil degradation in the ecologically fragile karst region of Southwest China, yet targeted vegetation restoration schemes remain poorly developed. This study aimed to screen promising selected restoration species and preliminarily explore their soil improvement characteristics in karst bauxite mine wastelands through a field observational survey. We investigated six vegetation-soil conditions at 0–10 cm topsoil (two-year monocultures of Robinia pseudoacacia, Ligustrum lucidum, Zea mays, Miscanthus sinensis, topsoil from >15-year Z. mays with straw return, and unvegetated bare land), alongside paired 10–20 cm subsoil from the same long-term Z. mays stand as a depth-profile reference, and analyzed soil physicochemical properties, enzyme activities, and bacterial/fungal communities via high-throughput sequencing. Results showed that vegetation cover neutralized strongly acidic mine soil and significantly increased soil organic matter (SOM), total nitrogen (TN), and available nutrients compared with the bare control (p < 0.05). The long-term Z. mays cropland showed the strongest soil nutrient accumulation, with topsoil SOM, available phosphorus, and available potassium, increased by 428.6%, 250.0%, and 65.3%, respectively, relative to the bare control. Notably, the subsoil of long-term Z. mays also maintained high nutrient levels, but its absolute values are not directly comparable with topsoil treatments due to different sampling depths. All vegetation conditions elevated soil enzyme activities and microbial alpha diversity and significantly shifted bacterial and fungal community structure (beta diversity) compared with the control. Several bacterial phyla (including Chloroflexi and Proteobacteria) that have been associated with carbon-cycling functions in prior studies were relatively more abundant in revegetated soils; however, their functional roles in this system remain to be verified. Redundancy analysis identified SOM, TN, and available potassium as key environmental correlates of bacterial community variation. Overall, the long-term crop–straw return pattern shows comprehensive soil improvement effects, providing observational baseline data and reference for ecological restoration of karst bauxite mining areas in Southwest China. Full article

Under intensifying climate change and increasingly frequent extreme heat events, improving outdoor thermal environments has become critical for sustainable human settlements. While prior studies have mainly focused on urban contexts, systematic investigations of rural microclimates—particularly regarding the regulatory mechanisms of landscape configurations—remain limited. This study examines a mountain-adjacent village in the Loess Tableland region of China, integrating field measurements with ENVI-met simulations to analyze thermal characteristics of rural road spaces and the effects of vegetation and paving materials on human thermal comfort. The results show that village boundary areas experience the largest fluctuations in air temperature and relative humidity during midday and evening, indicating higher thermal sensitivity. Model validation demonstrates satisfactory accuracy, with RMSE values of 0.39–3.62 °C for air temperature, 1.32–3.22% for relative humidity, and 1.35–2.24 m/s for wind speed, and MAPE ranging from 0.80% to 9.05%. Furthermore, Basalt Brick and Populus alba show the best cooling performance, but when considering multiple factors such as temperature, humidity, and wind speed, Ligustrum lucidum has the most significant effects in improving thermal comfort and increasing humidity. Analysis based on Physiological Equivalent Temperature (PET) further indicates that vegetation configurations play a more substantial role in thermal comfort regulation than paving materials, and that different landscape elements exhibit synergistic and trade-off relationships in terms of cooling, humidification, and ventilation. This study provides quantitative reference for vegetation configuration and material selection in rural roads within the Loess Tableland region and similar semi-arid areas, enriches the research scope of rural microclimate studies, and offers scientific support for climate-adaptive rural planning and optimization of rural living environments. Full article

The transformation of degraded stands represents an essential strategy for enhancing stand productivity and optimizing site adaptability. This study examined four typical monoculture forest stands transformed from underperforming Platycladus orientalis (PO) forests in the limestone area of Xuzhou, China: Acer pictum subsp. mono (AP), Pistacia chinensis (PC), Ligustrum lucidum (LL), and Firmiana simplex (FS). The contents of carbon (C), nitrogen (N), and phosphorus (P), along with the C:N:P stoichiometric ratios, were analyzed in plants (leaves and fine roots), litter, and soil. The relationships among these components and their main influencing factors were explored. The results indicated that FS leaves contained higher levels of N and P, whereas LL litter presented significantly elevated C:N and N:P ratios in comparison with those of the other forest stands (p < 0.05). With the exception of FS, leaves displayed lower P than fine roots, which presented pronounced P enrichment. The soil C, N, and P contents decreased with depth, with both the forest stand and depth significantly impacting the soil stoichiometry (p < 0.01). Redundancy analysis identified available potassium, total nitrogen, and microbial biomass carbon in the soil as key factors influencing the stoichiometric characteristics of the leaf–fine root–litter continuum. Collectively, the leaf N:P ratios (>16) and low soil P contents indicate that plantation growth was primarily constrained by P limitation. In response, AP, PC, and LL allocate more P to fine roots to adapt to the environment. Full article

Drought stress is a crucial factor limiting plant survival and growth, especially during the seedling establishment stage. A deep understanding of different plants’ responses to drought stress and their drought resistance is of great significance for vegetation restoration under drought conditions. This study selected one-year-old seedlings of Winter Jasmine (Jasminum nudiflorum), Oleander (Nerium oleander), Privet (Ligustrum lucidum), and Redleaf Photinia (Photinia × fraseri) as research objects. Through pot experiments, we investigated the physiological and biochemical responses of these shrubs under different levels of drought stress (control, mild, moderate, and severe drought stress, corresponding to 75%, 60%, 45%, and 30% of field maximum water holding capacity) to comprehensively assess their drought resistance capabilities. The research results indicated that as the level of drought stress increased, significant changes (p < 0.05) occurred in the physiological and biochemical indicators of all four plant species. The chlorophyll content (Chla+b) of Winter Jasmine and Redleaf Photinia gradually decreased with the intensification of stress, while the Chla+b of Oleander showed the most significant decline under moderate stress and Privet was most affected under mild stress. The proline (Pro) and soluble sugar (SS) contents of all four plants exhibited an upward trend, suggesting that the plants coped with drought stress by accumulating these osmoregulatory substances. Drought stress led to damage to plant cell membranes, manifested by an increase in malondialdehyde content (MDA), with Winter Jasmine showing the most pronounced increase. The activities of peroxidase (POD) and superoxide dismutase (SOD) in the four plant species responded differently to drought stress: the POD activity of Oleander and Redleaf Photinia increased with the deepening of stress, while that of Winter Jasmine and Privet decreased. A comprehensive evaluation of the drought tolerance of the four plant species was performed using principal component analysis and affiliation function value methods. The drought tolerance of the four shrubs, from strongest to weakest, was as follows: Redleaf Photinia > Oleander > Privet > Winter Jasmine. This finding provides valuable insights for plant selection in ecological slope protection projects, and Redleaf Photinia and Oleander can be promoted for use in vegetation restoration work under drought conditions. Full article

Cities are major contributors to global carbon emissions; however, urban parks offer substantial potential for carbon sinks. Research on factors influencing carbon capture in urban park vegetation is still limited. This study investigates 81 urban parks in Xinyang, Henan Province, to quantify woody plant carbon storage (CS) and sequestration (CSG). By surveying all vegetation types and quantities in these parks, along with factors like park attributes, community structure, biodiversity, spatial distribution, woody plant connectivity, and spatial complexity, we create statistical models for CS and CSG. The results indicate that the average carbon storage density (CSD) in Xinyang’s urban parks is 4.01 kg/m², while the carbon sequestration density (CSGD) is 0.39 kg·C·m²·yr⁻¹. The dominant tree species are Ligustrum lucidum, Osmanthus fragrans, and Lagerstroemia indica, while species with higher carbon sequestration potential, such as Glyptostrobus pensilis, Populus deltoides, and Albizia kalkora, reveal a discrepancy between common and high-sequestration species. The study shows that park characteristics, community structure, and biodiversity are key factors impacting urban carbon sink capacity. By analyzing the relationship between these factors and carbon sinks in urban park vegetation, we create a comprehensive framework for assessing tree CS and CSG, offering quantitative support to improve carbon capture in urban parks. Full article

The tree Ligustrum lucidum (W. T. Aiton, Oleaceae), native to East Asia (China), has become an aggressive invader of subtropical and temperate forests around the world. To understand how its local small-scale spread is controlled, we studied (48 plots of 4 m⁻²), in a subtropical forest of Uruguay, the distribution and survival of seedlings, saplings, and poles to assess the effects of dispersal from mother trees (distance), microsite type (forest stands defined by dominant species), and past control measures. The propagule pressure of L. lucidum, estimated through seedlings density, was between 100 and 1000 times higher than that of other species of the community and was concentrated around mother trees (<10 m of distance). Spatial variability of seedlings, saplings, and poles densities were explained by the interaction between distance to mother trees and forest stands. Significative lower densities were observed in the forest patches (stands) dominated by Jodina rhombifolia, and a field survival experiment confirmed lower survival of poles at Jodina stands, demonstrating that some resistance mechanism is operating there. We propose two biotic mechanisms of resistance: herbaceous competition and/or roots hemiparasitism by J. rhombifolia, reducing seedling and sapling survival. We concluded that a high propagule pressure, small-scale dispersal from mother trees, and patchy biotic resistance at Jodina stands control the local spread and domination process of the tree L. lucidum in the studied forest. Full article

In view of global climate and environmental challenges, exploring sustainable urban vegetation management and development is crucial. This study aims to investigate the design strategies of urban road green space plants under the guidance of the dual theories of carbon sequestration and cooling eco-efficiency and aesthetics. In this study, Yangling, a representative small- and medium-sized city, was selected as the study area, and road green space plants were identified as the research objects. The assimilation method was employed to ascertain the carbon sequestration and oxygen release, as well as the cooling and humidification capacities of the plants. The aesthetic quality of the plants was evaluated using the Scenic Beauty Estimation and Landscape Character Assessment. Finally, we propose design strategies for landscapes with higher aesthetic and carbon sequestration and cooling benefits. The results demonstrate a clear nonlinear positive correlation. The carbon sequestration and cooling benefits of plants and the aesthetic quality, with correlation coefficients of 0.864 and 0.922, respectively. Across the same sample points, the rankings of standardized values for carbon sequestration, cooling benefits, and aesthetic quality vary minimally. This indicates that eco-efficient plants with harmonious colors and elegant forms can boost the aesthetic appeal and ecological function in road green spaces. Furthermore, the Sophora japonica Linn., Ligustrum lucidum Ait., Koelreuteria paniculata Laxm., Prunus serrulata Lindl., Prunus cerasifera Ehrhar f., Ligustrum sinense Lour., Photinia × fraseri Dress, Ligustrum × vicaryi Rehder, Sabina chinensis (L.) Ant. cv. Kaizuca, and Ophiopogon japonicus (L. f.) Ker Gawl. are proved to be ecologically dominant plants. They can be employed as the principal selected species for plant design. This study summarizes applicable design strategies for three types of green spaces: avenue greenbelts, traffic separation zones, and roadside greenbelts. The nonlinear regression model developed here provides a reference for scientifically assessing and optimizing urban planting designs. Full article

The remediation and exploitation of sandy saline soils, an underutilized resource, can be enhanced by a greater comprehension of the impact of plants and microorganisms on nutrient cycling. However, there is scant research information on the capacity of different trees and shrubs to improve carbon and nitrogen cycling in saline soils at different depth layers. This study investigated the effect of the trees Zelkova serrata (ZS) and Ligustrum lucidum (LL) and shrub Hibiscus syriacus (HS) on the carbon and nitrogen fractions, soil enzyme activities and microbial communities in sandy saline soils. Planting ZS, LL or HS improved soil quality, increased soil carbon and nitrogen content, changed rhizosphere soil metabolites and enhanced soil enzyme activities and microbial abundance and diversity. Compared to values in the bare soil, the highest reduction in soil salinity was noticed under Zelkova serrata (49%) followed by Ligustrum lucidum (48%). The highest increase in total soil organic carbon (SOC) was noted under Ligustrum lucidum and Hibiscus syriacus (62% each), followed by Zelkova serrata (43%), as compared to levels in the bare soil. In the 0–10 cm soil layer, the total N in bare soil was 298 ± 1.48 mg/kg, but after planting LL, ZS or HS, the soil total N increased by 101%, 56% and 40%, respectively. Compared with that of the bare soil, cbbL sequencing showed that the relative abundance of Bradyrhizobium increased and that of Bacillus decreased due to planting. Similarly, the nifH sequencing results indicated that the relative abundance of Bradyrhizobium and Motiliproteu increased and that of Desulfuromonas and Geoalkalibacter decreased. These findings suggested that soil microorganisms could play a pivotal role in the carbon and nitrogen cycle of saline soils by influencing the content of soil carbon and nitrogen. Full article

Urban air pollution poses a significant threat to human health, with metropolitan areas particularly affected due to high emissions from human activities. Particulate matter (PM_x) is among the most harmful pollutants to human health, being composed of a complex mixture of substances related to severe pulmonary conditions. Urban green spaces play a vital role in mitigating air pollution by capturing PM_x, and it is essential to select plant species with a high capacity for PM_x accumulation to effectively enhance air quality. This study aimed to evaluate and compare the accuracy of two PM_x quantification methods—light microscopy and filtration—which demonstrated a high correlation (R² = 0.72), suggesting that both methods are reliable for assessing PM_x accumulation on leaves. Light microscopy allowed for the visualization of PM_x deposition, revealing the species warranting further analysis using the filtration method. Among the species analyzed, Euonymus japonicus, Ligustrum lucidum, Alnus glutinosa, Rubus ulmifolius, and Laurus nobilis demonstrated the highest total PM_x accumulation, exceeding 50 µg cm⁻², making them particularly valuable for air pollution mitigation. This study examined the correlation between leaf traits such as specific leaf area (SLA), leaf area (LA), leaf dissection index (LDI), and leaf roundness and PM_x accumulation across the 30 different plant species. A multiple linear regression analysis indicated that these leaf traits significantly influenced PM_x accumulation, with SLA and LA showing negative correlations and leaf roundness exhibiting a positive correlation with PM_x deposition. In conclusion, this study highlights the importance of selecting plant species with specific leaf traits for effective air quality improvement in urban environments particularly in highly polluted areas, to enhance air quality and public health. Full article

Fire is a prevalent hazard that poses a significant risk to public safety and societal progress. The continuous expansion of densely populated urban areas, exacerbated by global warming and the increasing intensification of urban heat islands, has led to a notable increase in the frequency and severity of fires worldwide. Incorporating measures to withstand different types of calamities has always been a crucial aspect of urban infrastructure. Well-designed plant communities play a pivotal role as a component of green space systems in addressing climate-related challenges, effectively mitigating the occurrence and spread of fires. This study conducted field research on 21 sites in the green belt around Shanghai, China, quantifying tree morphological indexes and coordinate positions. The spatial structure attributes of different plant communities were analyzed by principal component analysis, CRITIC weighting approach, and stepwise regression analysis to build a comprehensive fire resistance prediction model. Through this research, the relationship between community spatial structures and fire resistance was explored. A systematic construction of a prediction model based on community spatial structures for fire resistance was undertaken, and the fire resistance performance could be quickly judged by easily measured tree morphological indexes, providing valuable insights for the dynamic prediction of fire resistance. According to the evaluation and ranking conducted by the prediction model, the Celtis sinensis, Sapindus saponaria, Osmanthus fragrans, Koelreuteria paniculata, and Distylium racemosum + Populus euramericana ‘I-214’ communities exhibited a high level of fire resistance. On the other hand, the Koelreuteria bipinnata + Ligustrum lucidum, Ginkgo biloba + Camphora officinarum + Ligustrum lucidum, and Ligustrum lucidum + Sapindus saponaria communities obtained lower scores and were positioned lower in the ranking. It is emphasized that the integration of monitoring and regulation is essential to ensure the ecological integrity and well-being of green areas in the Wildland–Urban Interface. Full article

Natural regeneration is deemed essential for maintaining biodiversity and ecosystem stability. Previous studies, however, have primarily concentrated on regions exhibiting limited environmental and climatic variability, overlooking the classification of natural regeneration based on age and source. Research conducted at the mesoscale, characterized by increased environmental variability and the incorporation of neighborhood competition and understory-associated vegetation, enhances our comprehension of the multifaceted influences on natural regeneration. To comprehend this issue, this study implemented 60 plots, each measuring 20 m × 20 m, across five distinct areas of Chongqing, China. Twenty explanatory variables were chosen from five diverse categories: understory vegetation, neighborhood competition, stand structure, climatic factors, and environmental factors. And the naturally regenerated species were classified into seedlings and saplings, as well as endogenous and exogenous species, based on their age and origin. We examined the response of the different categories of natural regeneration to various factors and constructed a structural equation model (SEM) for significant factors to investigate their direct and indirect effects on natural regeneration. A total of 61 regenerated tree species belonging to 29 families and 42 genera were found in the study area, and the naturally regenerating species with high importance values were Quercus fabri, Robinia pseudoacacia, Alangium chinense, Cunninghamia lanceolata, and Ligustrum lucidum. It was found that neighborhood competition and understory-associated vegetation explained the largest proportion (more than 50%) of the variation in the different categories of natural regeneration, and forests with clumped distribution (W), a high mingling index (M) and strong competition (H) had a reduced natural regeneration capacity. Understory-associated herbs significantly reduced natural regeneration and the crowdedness index (C) significantly inhibited the understory-associated herbs, thus indirectly promoting natural regeneration. The shrub cover is significantly and positively correlated with the number of naturally regenerated plants and can be used as an indicator of a forest community’s regeneration potential. Understanding the differences in the importance of various factors at the mesoscale, as well as their direct and indirect impacts, can help us further comprehend the mechanisms of natural regeneration and provide a foundation for the sustainable development of forests. Full article

The present study emphasizes the importance of documenting ethnomedicinal plants and herbal practices of the local rural communities of Tehsil Hajira (Pakistan). The aim was to document, explore and quantify the traditional ethnomedicinal knowledge. Ethnobotanical data were collected using semi-structured questionnaires and analyzed using various quantitative indices. The results showed that 144 medicinal plant species from 70 families and 128 genera play an important role in herbal preparations. The most common type of preparation was powder (19.0%), followed by paste (16.7%), aqueous extract (15.7%), decoction (14.7%) and juice (11.0%). Fragaria nubicola (0.94) and Viola canescens (0.93) had the highest relative frequency of mention (RFC), while Berberis lycium (1.22) and Fragaria nubicola (1.18) had the highest use value (UV). Geranium wallichianum (85.5), Ligustrum lucidum (83) and Indigofera heterantha (71.5) were the most important species in the study area with the highest relative importance (RI) value. The diseases treated were categorized into 17 classes, with diseases of the digestive system and liver having the highest Informant Consensus Factor (ICF) value, followed by diseases of the oropharynx and musculoskeletal system. Important plants mentioned for the treatment of various diseases of the gastrointestinal tract are Zanthoxylum alatum, Berberis lycium, Mentha longifolia, Punica granatum, Rubus ellipticus and Viola canescens. New applications of rarely documented plants from this area are: Oxalis corniculata paste of the whole plant to treat vitiligo, Carthamus tinctorius flowers to treat chicken pox, Dioscorea deltoidea tuber powder to treat productive cough, Inula cappa root decoction to treat miscarriage, Habenaria digitata tuber juice for the treatment of fever, Viola canescens leaves and flowers for the treatment of sore throat and Achillea millefolium root and leaf juice for the treatment of pneumonia. These plants may contain interesting biochemical compounds and should be subjected to further pharmacological studies to develop new drugs. Traditional medicinal knowledge in the area under study is mainly limited to the elderly, traditional healers and midwives. Therefore, resource conservation strategies and future pharmacological studies are strongly recommended. Full article

As the urban heat island effect has become a worldwide phenomenon commonly affecting densely built-up areas, public administrations need efficient strategies to mitigate its impact on human well-being and public health. The aim of this study was to define a replicable method to estimate the ecosystem services provided by public street trees as a supporting tool in the decision-making process of urban greenery management. We compared three street arrangements characteristic of a residential district in Pisa, Italy: (1) with large trees, (2) with small trees, and (3) without trees. First, the software i-Tree Eco was used to assess the benefits of public trees located in the case-study area when provided with the three scenarios. Second, the comparison was held on the field, and we collected data with a wet bulb globe temperature meter in order to evaluate the differences in pedestrian thermal comfort among the street arrangements. The results confirmed the importance of urban vegetation, as it has major impacts on carbon sequestration and storage, pollution removal, air humidity and quality, and shade, given bigger trees and canopy sizes. The loss of ecosystem services compared to the presence of large trees varied between 40% and 50% (no trees) and 30% and 40% (small trees). Full article

Physiological variables (the content of chlorophyll, flavonoids and nitrogen, together with F_v/F_m) and the content of ten heavy metals (As, Cd, Cu, Hg, Mn, Ni, Pb, Sb, V and Zn) and two platinum group elements (PGEs: Pd and Rh) were measured in the leaves of 50 individuals of Ligustrum lucidum trees regularly distributed in the city of Logroño (Northern Spain). Three of these variables increased with increasing physiological vitality (chlorophyll, nitrogen and F_v/F_m), whereas flavonoids increased in response to different abiotic stresses, including pollution. Our aim was to test their adequacy as proxies for the pollution due to heavy metals and PGEs. The three vitality indicators generally showed high values typical of healthy plants, and they did not seem to be consistently affected by the different pollutants. In fact, the three vitality variables were positively correlated with the first factor of a PCA that was dominated by heavy metals (mainly Pb, but also Sb, V and Ni). In addition, F_v/F_m was negatively correlated with the second factor of the PCA, which was dominated by PGEs, but the trees showing F_v/F_m values below the damage threshold did not coincide with those showing high PGE content. Regarding flavonoid content, it was negatively correlated with PCA factors dominated by heavy metals, which did not confirm its role as a protectant against metal stress. The relatively low levels of pollution usually found in the city of Logroño, together with the influence of other environmental factors and the relative tolerance of Ligustrum lucidum to modest atmospheric pollution, probably determined the only slight response of the physiological variables to heavy metals and PGEs. Full article

The urban environment induces stress on trees and its impact can be identified by observing the condition of the crown. The aim of this study is to correlate the variables of crown density (Cdn), crown transparency (Ctr) and dieback (Cdie) with the following vegetation indices: the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), blue-normalized difference vegetation index (BNDVI), green-normalized difference vegetation index (GNDVI), green–red vegetation index (GRVI) and red–green–blue vegetation index (RGBVI) of the crowns of trees located in urban green areas, as well as chlorophyll fluorescence (Fv/Fm) as an indirect indicator of the overall tree health condition. A total of 549 trees were evaluated, represented in 24 families, 36 genera and 53 species; the variables had average values of 67.96% for Cdn, 35.19% for Ctr and 1% for Cdie. Correlations were found between Fv/Fm, NDVI and BNDVI. NDVI and BNDVI correlated with variables such as Cdn and Ctr, mainly in species such as Ligustrum lucidum, Jacaranda mimosifolia and Fraxinus uhdei. Therefore, it is possible to evaluate the tree health condition of trees in urban green environments through the identification of unfavorable conditions at the crown level by using vegetation indices for some of the species studied. Full article