Urban street trees are key to urban climate regulation, carbon storage and habitat provision, yet many cities still lack fine-scale, up-to-date field data on their structure and site conditions. Conventional tape and laser measurements are accurate but slow, labour-intensive and often impractical along narrow, obstacle-rich sidewalks. This study develops and tests a smartphone-based augmented-reality (AR) framework for measuring three ecologically critical geometric parameters of street trees—diameter at breast height (DBH), planting-pit area and tree spacing. Using general-purpose AR ruler apps on three consumer smartphones, we implemented a standardized field protocol and a generic geometric-plus-statistical calibration workflow that converts basal rectangular measurements into calibrated DBH. Field validation along a 1.5-km street corridor in Guangzhou, China (125 trees) shows that, after calibration, mean absolute percentage errors are 6–8% for DBH and below 3% for planting-pit area and spacing, satisfying Class B precision under the Chinese Regulations on Main Technical Specifications for Forestry Professional Surveys. AR workflows reduced survey time by 35–40% and required only one operator. The framework thus provides an operationally efficient, low-cost and transferable pathway to generate standardized structural data for urban-forest inventories and ecological-informatics applications.

Green facades (GFs) offer a promising strategy for improving building energy performance and indoor thermal comfort; however, their effectiveness is highly climate-dependent. This study presents a systematic cross-climate evaluation of direct green facades (DGFs) and indirect green facades (IGFs) across seven K & uml; oppen-Geiger climate zones using an EMS-integrated dynamic heat-transfer (DHT) model coupled with EnergyPlus simulations. Results show that DGFs generally achieve greater reductions in interior surface temperature, with a maximum decrease of 2.9 degrees C observed in the hot desert (Bwh) climate. In contrast, IGFs are more effective in reducing inward heat flux, reaching a peak reduction of 29.2 W/m2 in Bwh due to the additional thermal resistance provided by the air cavity. Cooling-load reductions are most significant in hot and high-radiation climates, where IGFs achieve the highest annual cooling-load saving rate of 13.12 % in Bwh, while DGFs outperform IGFs in the remaining climate zones. Heating-load reductions are generally more pronounced for IGFs in climates with non-negligible heating demand, such as Cfb, due to their enhanced insulation effect. Regarding indoor thermal comfort, both GF types reduce mean radiant temperature (T mrt ), with the largest improvement observed in the temperate oceanic climate (Cfb), where DGFs achieve a maximum reduction of 1.3 degrees C. Overall, the results demonstrate that GF performance is governed by the interplay between climatic conditions, facade configuration, and envelope thermal properties. These findings highlight the importance of climate-adaptive selection of green facade systems to maximize energy savings and thermal comfort benefits.

In the present study, we developed an efficient and reproducible protocol for in vitro regeneration and Agrobacterium tumefaciens-mediated genetic transformation of Broussonetia papyrifera (L.) L’Hér. ex Vent. (paper mulberry) using leaf explants from a hybrid genotype. First, we optimized surface sterilization of leaf explants. Treatment with 0.6% (w/v) sodium hypochlorite for 8 min, followed by three rinses with sterile water and blotting on sterile filter paper, yielded a 33.60% explant survival rate and reduced contamination to 35.84%. Second, we refined the co-cultivation step for transformation using A. tumefaciens strain EHA105 carrying pCAMBIA1300-35S-eGFP. Leaf discs were infected for 20 min and co-cultured for 2 days on co-cultivation medium overlaid with sterile filter paper, which limited the overgrowth of A. tumefaciens. After co-cultivation, explants were transferred sequentially to callus induction, shoot induction, shoot multiplication, and rooting media supplemented with 250 mg·L−1 cefotaxime and 200 mg·L−1 Timentin, as well as 5.0 mg·L−1 hygromycin at a concentration that completely suppressed regeneration of non-transformed explants. Meanwhile, after transfer to the callus induction medium, eGFP fluorescence was detected in resistant calli as an initial screening for transformants. The integration and expression of the transgene were further confirmed by PCR and quantitative reverse transcription PCR (qRT-PCR) after the resistant calli developed into plantlets. Collectively, this streamlined protocol provides a practical platform for functional genomics and genetic improvement of B. papyrifera.

Arid and semi-arid shelterbelts must provide long-term ecological protection under chronic water scarcity, high evaporative demand, and rising salinization risk, yet management still lacks an integrated framework linking irrigation, root-zone salt dynamics, and woody plant performance. Here, we synthesize evidence on water–salt–root linkages in drip-irrigated shelterbelts and related dryland woody systems from a structured Web of Science Core Collection search (1 January 2000–1 January 2026). The evidence shows that shelterbelt performance is governed not by water or salinity alone, but by a coupled root-zone system: localized irrigation creates moisture–salt heterogeneity, salts accumulate near evaporative fronts and emitter margins, and roots redistribute depth, density, and uptake zones. In hyper-arid saline-drip systems, precipitation may be only ~24.6 to <50 mm yr−1, evaporation > 3000–3639 mm yr−1, groundwater salinity 2.8–29.7 g L−1, active roots 20–80 cm, and salt mainly in the 0–20 cm surface layer. Irrigation thus acts as both the basis of establishment and a source of long-term vulnerability, particularly where saline groundwater or other non-conventional water sources are used. Management options can improve root-zone habitability, but shelterbelt-specific thresholds and integrated indicators remain limited. This review proposes a root-zone-centered framework supporting predictive regulation.

The ecosystem services of vertical greenery systems (VGSs) have attracted increasing research attention in recent decades. In addition to improving urban landscape esthetic and thermal comfort, VGSs also contribute to carbon (C) sequestration and CO2 uptake to mitigate climate change. In this study, the C storage and sequestration of six commonly used plant species (Coleus scutellarioides, Peperomia claviformis, Tradescantia spathacea, Duranta repens, Ficus elastica, and Heptapleurum heptaphyllum) in VGSs were determined over a year period. The C sequestration potential of the six plant species ranged from 60.6 to 248 g C m− 2 yr− 1, and T. spathacea was most effective in C sequestration. The net ecosystem CO2 exchange (NEE) of each plant species during different seasons were measured by using a portable chamber. The results revealed significant seasonal patterns in NEE, with peaking values occurring in summer. Additionally, the NEE values were higher for woody plants than for herbaceous plants. Correlation analysis indicated that the NEE of the VGSs was significantly affected by leaf area index (LAI), root biomass, and stomatal conductance. In addition, the indoor CO2 uptake rates of six plant species in VGSs were predicted under photosynthetically active radiation (PAR) = 200 and 450 µmol m− 2 s− 1. Among six plant species, H. heptaphyllum exhibited highest average indoor CO2 uptake rate throughout four seasons. Therefore, optimizing VGSs with woody plants featuring high NEE and biomass is critical for enhancing C sequestration and CO2 uptake within urban ecosystems.

Extensive research has emphasized indoor/outdoor thermal environments of building-scale vertical greenery systems (VGSs), yet comprehensive assessments of effects of street-scale VGSs on urban microclimates are scarce, with the relationship between greenery coverage ratios (GCRs) and cooling effects remaining unclear. This study determined the influence of VGSs on microclimate parameters in street canyons under different GCRs in a humid subtropical climate through scaled outdoor experiments. Key parameters included wind velocity (U0.25H), net radiation (Rn), urban canyon albedo (UCA), temperatures across various surfaces, namely west-facing walls (Twwest), east-facing walls (Tw-east), and ground (Tg), as well as air temperatures (Ta). Compared with the reference street canyon without VGSs, those with GCRs of 25%, 50%, and 100% experienced reductions in U0.25H by 10%, 20%, and 22%, respectively. Increased GCR was associated with higher Rn trapping and decreased UCA. Additionally, the reductions of Tw-west, Tw-east, and Ta increased with decreasing street canyon height. Higher GCRs tended to provide greater temperature reductions, longer cooling durations, and lower daily temperature range in street canyons. The reductions of Tw-east, Ta, and the central Tg within street canyons exhibited higher values with increasing GCR, reaching maximum reduction values of 15.7, 2.5, and 5.1 degrees C for a 100% GCR, respectively. Notably, the reduction of Tw-west in the lower level and of Tg adjacent to the west-facing wall of street canyon with a 50% GCR reached maximum values of 15.1 and 10.2 degrees C, respectively, exceeding the data with 25% and 100% GCRs.

Urban street trees improve urban life quality, but their root systems can conflict with infrastructure, especially in densely populated areas. Guangzhou-one of the world's most densely populated cities-experiences significant challenges related to street tree root-damage, which impacts urban infrastructure and public safety. This study examined factors affecting root-damage in 1227 street trees in Guangzhou's old urban areas, focusing on tree phenotypic parameters, planting environment, and root characteristics. Variables recorded included Tree height (TH), Crown width (CW), Diameter at breast height (DBH), root distribution, presence of buttress roots, and planting pit size. Logistic regression identified key factors influencing root-damage occurrence and severity. Results showed 30.9 % of trees exhibited root-damage. Shallow-rooted species such as Ficus microcarpa and Ficus altissima had higher root-damage rates (41 % and 47 %, respectively). Key predictors included DBH, planting pit size, and buttress roots. DBH was positively correlated with root-damage; larger planting pits reduced root-damage risk; and buttress roots increased root-damage likelihood. Trees with buttress roots were more likely to cause severe damage, and trees with DBH > 40 cm were prone to moderate and severe damage. These findings offer valuable insights for urban planners and forestry managers to optimize tree selection and planting strategies, mitigating root-damage and enhancing urban infrastructure resilience.

Broussonetia papyrifera is widely found in cadmium (Cd) contaminated areas, with an inherent enhanced flavonoids metabolism and inhibited lignin biosynthesis, colonized by lots of symbiotic fungi, such as arbuscular mycorrhizal fungi (AMF). However, the physiological and molecular mechanisms by which Rhizophagus irregularis, an AM fungus, regulates flavonoids and lignin in B. papyrifera under Cd stress remain unclear. Here, a pot experiment of B. papyrifera inoculated and non-inoculated with R. irregularis under Cd stress was carried out. We determined flavonoids and lignin concentrations in B. papyrifera roots by LC-MS and GC-MS, respectively, and measured the transcriptional levels of flavonoids- or lignin-related genes in B. papyrifera roots, aiming to ascertain the key components of flavonoids or lignin, and key genes regulated by R. irregularis in response to Cd stress. Without R. irregularis, the concentrations of eriodictyol, quercetin and myricetin were significantly increased under Cd stress. The concentrations of eriodictyol and genistein were significantly increased by R. irregularis, while the concentration of rutin was significantly decreased. Total lignin and lignin monomer had no alteration under Cd stress or with R. irregularis inoculation. As for flavonoids- or lignin-related genes, 26 genes were co-regulated by Cd stress and R. irregularis. Among these genes, BpC4H2, BpCHS8 and BpCHI5 were strongly positively associated with eriodictyol, indicating that these three genes participate in eriodictyol biosynthesis and were involved in R. irregularis assisting B. papyrifera to cope with Cd stress. This lays a foundation for further research revealing molecular mechanisms by which R. irregularis regulates flavonoids synthesis to enhance tolerance of B. papyrifera to Cd stress.

This study focuses on how the native broad-leaved tree species, Schima superba (Ss), influence the belowground ecological environment of the long-time pure Eucalyptus culture plantations (PCP) in South China. We selected five sites from each transformation mode: the continuing pure E. urophylla (Eu) culture plantation and the introducing Ss into pure Eu culture plantation, and collected litter and soil samples. For collected samples, we measured chemical and biochemical properties, and analyzed microbial community structure using Illumina MiSeq sequencing technology to investigate the effects of the five-year Ss introduction on soil properties and microbial community of the three-generation Eu PCP mode. The introduction of Ss increased total and available nutrients levels, except for the available potassium and pH. It also enhanced bacterial community richness. The relative abundance of WPS-2 in litter and soil layers increased, while that of Bacteroidetes, Planctomycetes, and Gemmatimonadetes in the litter layer decreased. Chloroflexi became the bacterial network core in the mixed Ss with Eu culture plantations (MCP) mode, replacing Planctomycetes, the core in the Eu PCP mode. For the fungal community, the introduction of Ss increased fungal community diversity and richness in the soil layer but decreased them in the litter layer. It also reduced the relative abundance of Basidiomycota while increasing that of Rozellomycota and Mucoromycota. Ascomycota became the fungal network core in MCP mode, replacing Basidiomycota, the core in Eu PCP mode. Therefore, our findings indicated that MCP mode simplified interactions within the microbial community while enhancing soil nutrient levels, recruiting bacteria form Chloroflexi or Verrucomicrobia, and fungi from copiotrophic Ascomycota, Eurotiomycetes, Rozellomycota or Mucoromycota to mineralize soil and decompose litter.

Rooftop Mitigation Strategies (RMSs) have garnered global recognition as effective measures for mitigating urban thermal environments. However, the cooling effectiveness of Green Roof (GR) and Cool Roof (CR) remains a subject of ongoing debate, especially when considered within diverse climatic contexts. This study conducted RMSs observation experiments within the subtropical urban landscape of Guangzhou, China, to assess the cooling potential of these strategies during both normal weather conditions and heatwaves. Our experiments identified a critical temperature threshold that influences the cooling potential of GR, a phenomenon rooted in vegetation transpiration. Below 33 degrees C, transpiration gradually intensifies, resulting in a noticeable cooling effect. However, as temperatures exceed this threshold, transpiration diminishes. Coupled with the aerodynamic drag imposed by vegetation leaves on wind flow, this complex dynamic leads to a temperature increase at heights ranging from 0.3 m to 0.6 m above the roof. Given the subtropical climate's characteristics of high temperatures and humidity, prudent consideration is warranted when selecting appropriate mitigation strategies. In this context, our observations suggest that CR may be a more cost-effective and potentially more efficacious choice due to their lower costs and substantial cooling potential. Our research provides a significant contribution to the reevaluation of RMSs' cooling potential and its role in reducing urban energy consumption and lowering building carbon emissions.

Scaled outdoor experiments were conducted to examine the thermal effects of west-facing green walls (GWs) in street canyons with different street aspect ratios (building height/street width H/W=AR=1, 1.5, and 2, H=1.2 m) under different weather conditions in humid-subtropical Guangzhou, China. Compared with the control cases (AR=1, 1.5, and 2), the wind speed at the height of 0.3 m (0.25H) was reduced by 15%-34% in GW cases under three weather conditions (sunny, cloudy and rainy). On a typical sunny day, significant wall temperature (Twall) reduction in GW cases was observed due to the thermal effects of GWs, with maximum values at 1.1 m (above the ground) reached 15.9, 21.2, and 22.1°C for AR=1, 1.5, and 2, respectively. The maximum ground temperature (Tground) reductions in GW cases were 1.5, 5.5, and 5.7°C as AR=1, 1.5, and 2, respectively. Moreover, GWs maximally reduced air temperature (Tair) at 0.1 m height (equal to the pedestrian level in real cities) by 0.5, 1.0, and 1.0°C when AR=1, 1.5, and 2, respectively. Compared with sunny days, the weaker solar radiation and higher relative humidity on cloudy and rainy days suppressed the thermal effects of GWs on Twall, Tground, and Tair in street canyons.

People spend up to 90% of their time inside buildings, making indoor air quality an extremely important factor affecting public health and building design. Due to the inherent ability to absorb/filter pollutants, plants present a promising method for improving indoor air quality. In recent decades, many studies have quantified plants’ effectiveness in removing indoor air pollutants using both chamber and field methods. This paper presents a review working covering these studies and discusses the differences between chamber and field studies, in terms of study methods and results. Through a meta-analysis of 41 chamber studies and 16 field studies, the effectiveness of 182 species in removing 25 pollutants has been estimated. From this work, a larger proportion of significant results were observed in chamber studies (88%), comparing to field studies (65%). Additionally, comparable studies revealed greater removal effectiveness of plants in chamber studies. These discrepancies could be attributed to many factors, such as the size and the airtightness of experimental setup, ventilation, gas exposure scheme, and environmental conditions. It is envisaged that these findings will help reduce the gap between chamber studies and field studies, and provide guidance for the future use of plants in buildings to improve indoor air quality.

随着城市化的推进,城市绿地的水平空间越来越稀缺,城市化进程中的环境压力和生活方式的改变逐渐影响城市居民的身心健康,而垂直绿化作为一种创新的城市绿地形式,对改善居民身心健康有重要作用.文中从城市空气质量、热舒适性、噪音以及城市居民情绪4个方面综述垂直绿化对城市居民身心健康的影响,阐述垂直绿化在提升城市居民生活质量方面的潜力,分析植被特征、空间特性、结构特征和气象条件对垂直绿化健康效益的影响,建议加强各学科交叉融合、明确垂直绿化发挥健康效益的机制、建立更加细致的研究指标体系、增加对特定人群的研究,以期为未来的研究和实践提供指导.

Root damage from urban street trees represents a substantial concern arising from the conflict between root growth and limited growth spaces. Nonetheless, the phenomenon of root damage, which threatens the safety of urban facilities, appears to have received little scholarly attention. Moreover, the effectiveness of some proposed measures for root damage prevention and control has not yet received consistent evaluation. Accordingly, this review aims to examine root damage, including its causes and available prevention and control measures. Urban trees are found to have a high potential to exert root damage on infrastructures when the following factors exist. These include large and mature tree, fast-growing trees, trees planted in limited soil volumes, shallow-rooted tree with buttress roots, trees whose diameter at breast height exceeds 10 cm, old and cracked road paving, high soil surface moisture content, short distances between trees and sidewalks (<2 to 3 m), and underground pipes that are already broken and made of metals or stones. The phenotypic traits of trees may be the primary factor causing root damage when there is a mismatch between the root-soil requirements of urban street trees and the actual soil environment. The poor effectiveness of root damage prevention and control measures may be attributed to the lack of connection between the development of control measures and the mechanism of root damage.

Vertical greenery system（VGS） which integrates buildings, plants and materials is an important approach to regulate the urban microclimate environment and alleviating the heat island effect. This paper analyzes the research literature on the influences of VGSs on urban microclimate, explores the four mechanisms behind the influences to analyze the effects of VGSs on the temperature, humidity, wind speed and urban heat island effect, and points out that VGSs regulating urban microclimate is influenced by the type of VGSs, plant characteristics, growth substrate and climatic conditions. On this basis, the future research directions of VGSs are summarized in order to provide references for the improvement of urban environment.

Vertical greenery systems (VGSs) have been proven to greatly improve the urban thermal environment. However, their effect on the retention of airborne particulate matter (PM) in the road environment remains unclear. This study aimed to assess the quantity of size-segregated PMs on both the upper (adaxial) and lower (abaxial) leaf surfaces, the mass of size-segregated PMs on the leaf surface and within the leaf wax, as well as the elemental composition of PMs retained in leaf stomata of four plant species in VGSs in Guangzhou. The findings revealed that VGSs exhibited greater retention of fine (<2.5 μm) PMs when compared to coarse (2.5–10 μm) and large (>10 μm) PMs. Among the four species studied, Tradescantia spathacea exhibited the highest PM retention in VGSs. The number density of accumulated PMs on the upper and lower leaf surfaces of the four plant species of VGSs at three heights varied significantly with species, heights, and their interaction (P < 0.05). The greatest stomatal block rate by PM occurred at a height of 0.6 m, the range was 91.1%–98.0%. The composition of PMs retained by the leaves primarily consisted of common element of C, O, Ca, K, Mg, and Si, which likely originated from natural sources. Heavy metals (HMs) such as Cr and Cd may have originated from brakes, while Zn and Cu might be attributed to tire wear and exhaust emissions. Therefore, VGSs effectively retained a substantial quantity of airborne PM and contributed to the mitigation of urban air pollution issues.

Camellia oleifera is a major woody oilseed species in China, but it is typically cultivated in nutrient-poor soils and may be affected by various trace elements. This study examined how spraying selenium, boron, and zinc trace elements affected the traits and functional active compounds of C. oleifera under nutrient deficiency. The results revealed significant variations in the effects of different trace element combinations on C. oleifera. Optimal concentrations of zinc and selenium are critical for promoting the growth and development of C. oleifera fruit. The transverse diameter of the fruit, the single fruit weight, the number of seeds per fruit, the single fresh seed weight, the oil content in the fruit, and the oil yield per plant of other treatments can be increased by up to 3.07%, 10.57%, 23.66%, 30.23%, 7.94%, and 21.95%, respectively, at most, compared to the control group. Diluting zinc from 1000 to 1500 times and maintaining a selenium concentration from 100 to 200 mg/L has been found to be beneficial for fruit growth. While low concentrations of selenium may promote an increase in fruit transverse diameter, high concentrations of selenium, along with high dilutions of zinc, can have the opposite effect, leading to a reduction in fruit diameter. However, a high concentration of selenium can positively impact the number of seeds per fruit. The most effective combination was found to be a selenium concentration of 0 mg/L, a boron concentration of 4 mg/L, and a zinc dilution of 1500. Interestingly, lower concentrations of selenium and boron, as well as lower dilutions of zinc, were found to increase the oil yield per plant. This suggests that a careful balance of trace elements is required to promote both fruit growth and oil content. The total sterol, squalene, total flavonoid, and polyphenol content of other treatments can be increased by up to 28.81%, 32.07%, 188.04%, and 92.61%, respectively, at most, compared to the control group. Selenium fertilizer and boron fertilizer increased the total sterol content in Camellia oil and had a significant positive correlation at the 0.01 level, but zinc fertilizer had little influence on it. High concentration selenium fertilizer generally increased the squalene, total flavonoid, and polyphenol content in Camellia oil, but boron and zinc fertilizers had little effect on these components. The results suggested that choosing appropriate fertilizer combinations could improve nutrient deficiency in C. oleifera and enhance the functional active compounds of its oil, thereby enhancing its value.

Vertical greenery system (VGS) is a sustainable solution to promote building energy saving and emission reduction, mitigate the urban heat island effect, as well as a crucial component of urban ecological construction. We summarized four main mechanisms of the thermal effects of VGSs, including shading effect, evapotranspiration effect, thermal insulation effect, and wind control effect. We elucidated the effects of VGSs on building cooling and energy saving, and analyzed the cooling effects of VGSs on plant canopy and outdoor ambient air, as well as their influence on mitigating the urban heat island effect. Based on available research on the thermal effects of VGSs, we identified key directions for future research, aiming to expedite the development of green cities and achieve carbon neutrality.