Search Results (108)

Optimizing olive orchard management requires timely, per-tree data to enhance productivity and sustainability. Unoccupied aerial vehicle (UAV)-based red, green, and blue (RGB) imagery offers a low-cost solution for acquiring high-resolution spatiotemporal insights for orchard management, which are not yet common in Tunisia. This study monitored tree structural parameters, leaf area index (LAI), and leaf nitrogen content (%N DW) in two Tunisian olive orchards during 2022 and 2023. UAV-derived imagery was photogrammetrically processed into 3D point clouds and analyzed using an automated approach. Target variables of the automated approach included tree-wise estimates of height, projected crown area, and crown volume, as well as raster cell counts of the canopy cloud and spectral indices such as the normalized green-red difference index (NGRDI) and green leaf index (GLI). In addition, the estimated parameters per tree were used to model LAI and leaf nitrogen content. Analyses were conducted separately for trees represented by a high and a low number of points in the dense point cloud. Outcomes were compared to reference data collected in the field on dates close to the UAV flights. The findings showed strong relationships for the projected crown area (R² = 0.82 and 0.91) and tree height (R² = 0.89 and 0.88) when compared to reference values. Linear regression models for LAI (R² = 0.73 and 0.68) and crown volume (R² = 0.85 and 0.91) estimation also show strong relationships. However, leaf nitrogen estimation was not feasible from RGB spectral index values, as it showed a weak relationship (R² = 0.34). A dataset with multispectral imagery could overcome this limitation but would increase costs, making it less suitable for the low-budget approach required in price-sensitive farming contexts, particularly in low-income regions. Full article

Ensuring the stability of the surrounding rock is the primary objective in the construction of an underground powerhouse at a hydropower station. Real-time monitoring, stability assessment, and evolutionary trend prediction of surrounding rock deformation and support structure stress are essential for maintaining rock mass stability. Using safety monitoring data and numerical simulation, the evolutionary behaviour of surrounding rock deformation and rock bolt stress during construction of the Kala Hydropower Station underground powerhouse was analysed. Surrounding rock stability and its future state were evaluated. Deformation in the first to third layers was mainly controlled by excavation disturbance and local geological conditions. The crown within the influence zone of the F152 fault exhibited the maximum deformation of 14.60 mm, whereas deformation in other areas was relatively small. Surrounding rock deformation in the cavern remained safe. Rock bolt stress showed spatio-temporal consistency with deformation, with maximum values concentrated in fault-cutting areas. The proportion of anchor bolts with stress below 200 MPa was 96.3%, indicating that the overall stress on the rock bolts in the cavern was in a safe state. Numerical simulation results predict that significant deformation during subsequent excavation and support will be concentrated between faults F152 and F75. The maximum surrounding rock deformation may occur in the fifth-layer sidewall affected by the F75 fault. Relatively high rock bolt stress is expected in the fifth to seventh layer sidewalls influenced by the F152 fault. This study identifies potential locations and development characteristics of stability deterioration during subsequent construction, providing guidance for construction design. The results serve as a reference for surrounding rock stability evaluation and prediction in similar underground powerhouse projects. Full article

Forests provide a wide range of ecosystem services, and their importance in supporting human well-being is widely recognized. As goods and benefits from forests are exhaustible, it is therefore essential to gather sound data for their monitoring and management. Remote sensing has gained increasing importance in collecting data on forests, driven by the growing demand for regularly updated environmental data. However, remote sensing modeling of vegetation requires reference data to be collected in the field. This article presents a dataset on tree crown cover—both total and by species—of 528 georeferenced forest plots located in the Eastern Alps, Italy, an area affected by extensive wind and snow damage and subsequent widespread damage caused by bark beetles. The characteristic species of the forest types in the dataset are widely distributed over the Eurasian continent, making the dataset potentially useful to many users and researchers studying forest biodiversity or remote sensing applications to monitor forest cover changes. Data were collected within a still ongoing project aimed at detecting crown cover changes in small forest patches. Full article

To investigate the impact of subsurface karst cavities on the stability of pipe jacking construction, this study utilizes the Yunnan Central Water Diversion Project as a real-world case. Employing ABAQUS finite element software to establish a numerical model, it systematically analyzes construction stability under the specific condition of “karst cavities present ahead of the excavation direction” in karst formations. The research focuses on examining the effects of four key scenarios on the displacement and stress response of surrounding rock and pipe segments. These conditions specifically include the following: tunnel burial depth (10 m, 15 m, 20 m, 25 m), cavity diameter beneath the tunnel (1–4 m), cavity filling status, and distance between the cavity and the tunnel (1–4 m). The study reveals that in composite stratum tunnel construction, when cavities exist in the strata ahead, multi-area displacements increase progressively with cavity size. Displacement changes accelerate and magnify when the cutting face of the jacking machine approaches within approximately 2.5 m of the cavity. However, no significant difference is observed between soft plastic clay reinforcement and slurry reinforcement effects. When composite stratum tunnels traverse beneath karst caves, the maximum upward bulge at tunnel bases occurs at 1-meter diameter caves, reaching approximately 2.5 mm. When the diameter of the cave increases to 4 m, the arching settles to a maximum. As tunnel burial depth increases, the arch base rises while the crown sinks, with settlement magnitude exceeding bulge amount. The displacement and stress fields from the initial excavation phase become disturbed, intensify, and then stabilize. When the jacking machine reaches directly above the cavern, stress at the crown base increases while stress at the crown top decreases. The pipe bottom exhibits uplift, and the pipe top shows reduced settlement directly above the cavern. Cavern filling has a minor effect on pipe-segment displacement, with segments deforming into an approximate elliptical shape. At the completion stage of excavation, the maximum Mises stress occurs at the top of the launch-end pipe segment. While cavern-related factors have a limited influence on the pipe-segment Mises stress, this stress gradually increases as excavation progresses. Full article

Heavy rainfall infiltration is a key disaster-inducing factor that triggers the softening of surrounding rock and deformation of support structures in tuff gully tunnels. Based on the gully section of the left line of the Dabao Tunnel of the Leigongshan–Rongjiang Expressway in Guizhou Province, this study systematically reveals the synergistic disaster-inducing mechanism of “topography-seepage-softening” in tuff gully tunnels under heavy rainfall infiltration through laboratory tests and FLAC3D 3D numerical simulations. The main innovative conclusions are as follows: (1) The “phased” attenuation law of tuff mechanical parameters was quantified, and the critical water content for significant strength deterioration was determined to be 2.5%, with a saturated softening coefficient of 0.59. These results provide key data for early warning and evaluation of similar projects. (2) A “convergence-disorder” distribution pattern of pore water pressure controlled by gully topography was revealed. It was found that the rock mass directly below the aqueduct exhibits a disordered zone with downward-extending pore water pressure due to fluid convergence, with the maximum pore water pressure reaching 0.55 MPa. This clarifies the essence that tunnel stability is controlled by the coupling of topography and seepage field. (3) The key sensitive areas for tunnel stability—namely the gully bottom, arch haunches, and the area below the aqueduct—were accurately identified. The significant increase in displacement of these areas after rock stratum softening was quantified (e.g., the displacement at the crown of the secondary lining increased from 3 mm to 4 mm, and the influence range expanded to the arch haunches). This study clarifies the deformation characteristics and instability mechanism of tuff gully tunnels under heavy rainfall from two aspects: the “internal mechanism of rock mass softening” and the “external condition of topographic seepage control.” It can provide a theoretical basis and key technical pathway for disaster prevention and control as well as stability design of similar tunnels. Full article

The increasing frequency and intensity of wildfires pose severe risks to ecosystems, infrastructure, and human safety. In wildland–urban interface (WUI) areas, nearby vegetation strongly influences building ignition risk through flame contact and radiant heat exposure. However, limited research has leveraged Unmanned Aerial Systems (UAS) remote sensing (RS) to capture species-specific vegetation geometry and predict thermal responses during ignition events This study proposes a two-stage framework integrating UAS-based multispectral (MS) imagery, LiDAR data, and Fire Dynamics Simulator (FDS) modeling to estimate the maximum temperature (T) and heat flux (HF) of outdoor vegetation, focusing on Syzygium smithii (Lilly Pilly). The study data was collected at a plant nursery at Queensland, Australia. A total of 72 commercially available outdoor vegetation samples were classified into 11 classes based on pixel counts. In the first stage, ensemble learning and watershed segmentation were employed to segment target vegetation patches. Vegetation UAS-LiDAR point cloud delineation was performed using Raycloudtools, then projected onto a 2D raster to generate instance ID maps. The delineated point clouds associated with the target vegetation were filtered using georeferenced vegetation patches. In the second stage, cone-shaped synthetic models of Lilly Pilly were simulated in FDS, and the resulting data from the sensor grid placed near the vegetation in the simulation environment were used to train an XGBoost model to predict T and HF based on vegetation height (H) and crown diameter (D). The point cloud delineation successfully extracted all Lilly Pilly vegetation within the test region. The thermal response prediction model demonstrated high accuracy, achieving an RMSE of 0.0547 °C and R² of 0.9971 for T, and an RMSE of 0.1372 kW/m² with an R² of 0.9933 for HF. This study demonstrates the framework’s feasibility using a single vegetation species under controlled ignition simulation conditions and establishes a scalable foundation for extending its applicability to diverse vegetation types and environmental conditions. Full article

To address the problems of traditional methods that rely on destructive sampling, the poor adaptability of fixed equipment, and the susceptibility of single-view angle measurements to occlusions, a non-destructive and portable device for three-dimensional phenotyping and biomass detection in lettuce was developed. Based on the Structure-from-Motion Multi-View Stereo (SFM-MVS) algorithms, a high-precision three-dimensional point cloud model was reconstructed from multi-view RGB image sequences, and 12 phenotypic parameters, such as plant height, crown width, were accurately extracted. Through regression analyses of plant height, crown width, and crown height, and the R² values were 0.98, 0.99, and 0.99, respectively, the RMSE values were 2.26 mm, 1.74 mm, and 1.69 mm, respectively. On this basis, four biomass prediction models were developed using Adaptive Boosting (AdaBoost), Support Vector Regression (SVR), Gradient Boosting Decision Tree (GBDT), and Random Forest Regression (RFR). The results indicated that the RFR model based on the projected convex hull area, point cloud convex hull surface area, and projected convex hull perimeter performed the best, with an R² of 0.90, an RMSE of 2.63 g, and an RMSEn of 9.53%, indicating that the RFR was able to accurately simulate lettuce biomass. This research achieves three-dimensional reconstruction and accurate biomass prediction of facility lettuce, and provides a portable and lightweight solution for facility crop growth detection. Full article

With the rapid advancement of urban underground space development, shield tunnel construction has seen a significant increase. However, at the initial launching stage of shield tunnels in shallow-buried weak strata, engineering risks such as face instability and sudden surface settlement frequently occur. At present, there are relatively few studies on the reinforcement technology of the initial section of shield tunnel in shallow soft ground and the evolution law of ground disturbance. This study takes the launching section of the Guanggang New City depot access tunnel on Guangzhou Metro Line 10 as the engineering background. By applying MIDAS/GTS numerical simulation, settlement monitoring, and theoretical analysis, the reinforcement technology at the tunnel face, the spatiotemporal evolution of ground settlement, and the mechanism of soil disturbance transmission during the launching process in muddy soil layer are revealed. The results show that: (1) the reinforcement scheme combining replacement filling, high-pressure jet grouting piles, and soil overburden counterpressure significantly improves surface settlement control. The primary influence zone is concentrated directly above the shield machine and in the forward excavation area. (2) When the shield machine reaches the junction between the reinforced and unreinforced zones, a large settlement area forms, with the maximum ground settlement reaching −26.94 mm. During excavation in the unreinforced zone, ground deformation mainly occurs beneath the rear reinforced section, with subsidence at the crown and uplift at the invert. (3) The transverse settlement trough exhibits a typical Gaussian distribution and the discrepancy between the measured maximum settlement and the numerical and theoretical values is only 3.33% and 1.76%, respectively. (4) The longitudinal settlement follows a trend of initial increase, subsequent decrease, and gradual stabilization, reaching a maximum when the excavation passes directly beneath the monitoring point. The findings can provide theoretical reference and engineering guidance for similar projects. Full article

Phalaenopsis is a widely cultivated ornamental plant of considerable economic value worldwide. However, traditional growing medium, sphagnum moss, is limited and non-renewable. It also decomposes slowly and is prone to environmental issues. Therefore, there is an urgent need to identify more environmentally friendly and efficient alternatives. Biochar, a sustainable material with excellent physical and chemical properties, has been recognized as an effective promoter of plant growth. In this study, we investigated the influence of biochar derived from three raw materials (corn straw, bamboo, and walnut) mixed1 with coconut shell at ratios of 1:2, 1:10, and 4:1, on the growth of Phalaenopsis ‘Big Chili’. Over a 150-day controlled experiment, we evaluated multiple growth parameters, including plant height, crown width, total root length, total projected area, total surface area, and root volume. Compared to the traditional growing medium, the optimal biochar-coconut shell mixture (maize straw biochar: coconut shell = 1:2) increased plant height and crown width by 7.55% and 6.68%, respectively. Root metrics improved substantially, with total root length increasing by 10.96%, total projected area by 22.82%, total surface area by 22.14%, and root volume by 38.49%. Root biomass in the optimal treatment group increased by 42.47%, while aboveground and belowground dry weights increased by 6.16% and 77.11%, respectively. These improvements were closely associated with favorable substrate characteristics, including low bulk density, high total and water-holding porosity, moderate aeration, and adequate nutrient availability. These findings demonstrate that substrate characteristics critically influence plant performance and that biochar–coconut shell mixtures, particularly at a 1:2 ratio, represent a viable and sustainable alternative to sphagnum moss for commercial cultivation of Phalaenopsis. Full article

The almost complete eradication of fire from grasslands in North America has led to non-linear hysteretic transitions to shrub- and woodlands that the reintroduction of low-intensity fire is unable to reverse. We explore the ability of the extreme ends of variation in fire behavior to help overcome hysteretic threshold behaviors in huisache (Vachellia farnesiana) encroached grasslands. We contrasted experimental fire treatments with unburned control areas to assess the ability of extreme fires burned during drought to alter the density and structure of huisache. We found that extreme fires reduced the density of huisache by over 30% compared to control plots, both through driving huisache mortality and reducing the number of new recruits following treatments. For instance, extreme fire drove 48% huisache mortality compared to 4% in control treatments. For surviving plants, the number of stems increased but the crown area did not significantly change. Prescribed fire, conducted under the right conditions, can drive high mortality in one of the most notorious encroaching species in the southern U.S. Great Plains. With the fire conditions observed in this study likely to increase under future climate projections, utilizing extreme fire as a management tool for huisache will help scale up management to meet the growing extent of woody encroachment into grasslands. Full article

Accurate individual tree segmentation (ITS) in dense rubber plantations is a challenging task due to overlapping canopies, indistinct tree apexes, and intricate branch structures. To address these challenges, we propose a bottom-up, multi-feature fusion method for segmenting rubber trees using UAV-LiDAR point clouds. Our approach first involves performing a trunk extraction based on branch-point density variations and neighborhood directional features, which allows for the precise separation of trunks from overlapping canopies. Next, we introduce a multi-feature fusion strategy that replaces single-threshold constraints, integrating geometric, directional, and density attributes to classify core canopy points, boundary points, and overlapping regions. Disputed points are then iteratively assigned to adjacent trees based on neighborhood growth angle consistency, enhancing the robustness of the segmentation. Experiments conducted in rubber plantations with varying canopy closure (low, medium, and high) show accuracies of 0.97, 0.98, and 0.95. Additionally, the crown width and canopy projection area derived from the segmented individual tree point clouds are highly consistent with ground truth data, with R² values exceeding 0.98 and 0.97, respectively. The proposed method provides a reliable foundation for 3D tree modeling and biomass estimation in structurally complex plantations, advancing precision forestry and ecosystem assessment by overcoming the critical limitations of existing ITS approaches in high-closure tropical agroforests. Full article

In July 2024, the “Investigating the Archaeology of Death in Pompeii Research Project” carried out a scientific and methodical excavation of the areas outside two of the gates to the city of Pompeii. One of them is the funerary area of Porta Nola (next to the tomb of Obellio Firmo) and the other is outside Porta Sarno area (east of the tomb of Marcus Venerius Secundius). The investigated funerary area to the east of Porta Sarno corresponds with the area excavated in 1998 for the construction of the double Circumvesuviana rails. The 1998 excavations recorded the presence of more than 50 cremation burial sites, marked by stelae (columelle) and a monument with an arch, which are delineated by a boundary wall. The tombs were initially dated to the Late Republican period. In order to carry out comprehensive studies of the funerary area uncovered in 1998, a four metre by four metre trench was stratigraphically excavated. This investigation allowed mapping of the area and the carrying out of archaeological analysis and bioarchaeological studies in order to answer the questions that guided our archaeological research, such as whether the funerary area was abandoned and, if so, when? What was the chronological succession, monumentality, and prestige of this funerary space? Was it a single family and private funerary enclosure, or was it an open public space? How were this funerary area and the spaces destined to preserve the memory of the deceased managed? How were the funerary and mortuary rituals and gestures articulated and what did they consist of? Our methodical excavation discovered a monumental tomb which allows us to answer many of the questions raised by our research. This extraordinary monument consists of a wide wall with several niches containing the cremated remains of the deceased built into its structure and which is crowned by a relief of a young couple. The symbolism of the carved accessories of the wife may identify her as a priestess of Ceres. Additionally, the quality of the carving in the sculptures and their archaic characteristics suggest a Republic period dating, which is uncommon in southern Italy. Full article

The study aims to analyze morphological variations and spatial distribution patterns of Krascheninnikovia compacta (Losinsk.) Grubov communities across 12 sampling areas at different elevations in the Tibetan antelope breeding grounds of the western Kunlun Mountains. Additionally, it projected the future climatically suitabie habitats of K. compacta under climate change scenarios, aiming to elucidate its community characteristics, spatial distribution dynamics, and the impacts of global warming on its growth. Integrated GIS, remote sensing, and unmanned aerial vehicles (UAVs) were used to investigate K. compacta communities. The Pearson correlation analysis revealed significant correlations between crown diameter, as well as between plant height and environmental factors. The redundancy analysis (RDA) results indicated that multiple environmental factors jointly explained the variation in plant height and crown diameter of K. compacta. Point pattern analysis, using the g(r) function combined with two null models, demonstrated changes in plant distribution during scale transitions. Additionally, the MaxEnt model was employed to project the potential suitable habitats of K. compacta under future climate scenarios. Overall, as the elevational gradient increases, the plant height of K. compacta gradually decreases while the crown diameter expands. Mean annual temperature (MAT) dominates the morphological variations in crown diameter and plant height, with lower temperatures correlating to shorter plant height and larger crown diameter. The complete spatial randomness (CSR) model indicates that across all elevations, the distribution patterns of plants transition sequentially from uniform to random, then clustered, and back to random as spatial scale increases. The heterogeneous Poisson (HP) model suggests that habitat heterogeneity is the primary driver of shifts in plant distribution patterns at larger scales. The MaxEnt model revealed distinct changes in suitable habitat areas of K. compacta under future climate scenarios. During 2061 to 2080s, its suitable habitats under the SSP126 and SSP585 pathways significantly contracted and expanded markedly, respectively. Full article

Accurate estimates of aboveground biomass (AGB) are essential for forest policies to reduce carbon emissions. Unmanned aerial laser scanning (UAV-LS) offers unprecedented millimetric detail but is underutilized in monitoring broadleaf Mediterranean forests compared to coniferous ones. This study aims to design and evaluate a procedure for AGB estimates based on the predictive power of crown features. In the first step, we manually created Quantitative Structure Models (QSMs) for 320 trees using data from UAV laser scanning (UAV-LS), airborne laser scanning (ALS), and co-registered terrestrial laser scanning (TLS). This provided the most accurate non-destructive estimate of aboveground biomass (AGB) in the absence of destructive measurements. For each reference tree we also measured crown projection and crown volume to build two separated models relating AGB to such crown features. In the second phase, we evaluated the potential of UAV-LS for quantifying AGB in a pure European beech (Fagus sylvatica) forest and compared it with traditional ALS estimates, using fully automatic procedures. The two obtained tree-level AGB models were then tested using three datasets derived from 35 sampling plots over the same study area: (a) 1130 trees manually segmented (phase-2 reference); (b) trees automatically extracted from ALS data; and (c) trees automatically extracted from UAV-LS data. Results demonstrate that detailed UAV-LS data improve model sensitivity compared to ALS data (RMSE = 45.6 Mg ha⁻¹, RMSE% = 13.4%, R2 = 0.65, for the best ALS model; RMSE = 44.0 Mg ha⁻¹, RMSE% = 12.9%, R2 = 0.67, for the best UAV-LS model), allowing for the detection of AGB differences even in quite homogenous forest structures. Overall, this study demonstrates the combined use of both laser scanner data can foster non-destructive and more precise AGB estimation than the use of only one, in forested areas across hectare scales (1 to 100 ha). Full article

This article offers the architectural definition and interpretative keys to a unique project. It is a space shared by the three main Abrahamic faiths: the Jewish, Christian and Muslim religions. Although conceptually other religions could be accommodated. Its configuration is very elementary: a cubic volume, massive and almost blind, with a cylindrical space crowned by a simple skylight. Each of the religions is based on a scratching of the interior surfaces of the space, forming the ritual areas of each of them. And towards the center of the space there are other areas of prayer and celebration that could be shared among the believers of the different religions, from the conviction that they are addressed to the same God. In this configuration there is a will of invitation, of offering to all men of good will. The article, written by the architect of this space, mentions some plastic and conceptual references that have served as inspiration for the project and its presentation is intended to fuel the debate on the possibility of this space. Full article