Search Results (31)

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

Ecological determinants of avian population dynamics are essential for effective wildlife management and conservation. Black and grey francolins are classified as being of least concern by the IUCN and are an ecologically significant bird in the northern regions of Pakistan. Although habitat degradation and overhunting have adversely affected their populations, research on the population structure and habitat preferences of the Totali Game Reserve, Buner District, Pakistan, remains limited. The present study applied distance sampling via the line transect method to estimate population densities and the quadrat method to assess vegetation characteristics across three distinct habitats. A statistical analysis revealed significant variations in densities across the three habitat types—agricultural lands, agroforests, and pasturelands—with both species exhibiting distinct preferences for pastureland ecosystems. Seasonal trends indicated that autumn represented the peak period for the population, driven by post-breeding surges and optimal habitat conditions. Moreover, both species demonstrated a strong affinity for habitats dominated by specific plant species, including hopbush, raspberry, barberry, and blackberry, which provide a critical resource for food, foraging, nesting, and shelter. These findings highlight the ecological importance of pasturelands and specific vegetation types for supporting the survival of these species. Furthermore, conservation efforts should prioritize the preservation and restoration of pastureland ecosystems and incorporate rigorous monitoring programs to guide adaptive management strategies aimed at mitigating population declines. Full article

Studies on the spatiotemporal dynamics in ecosystem carbon and water exchanges are essential in predicting the effects of climate change on regional carbon and energy budgets. Using the eddy covariance technique, carbon and water fluxes were observed in a typical winter wheat ecosystem (WWE) and an agroforest ecosystem (AFE) in the southern Loess Plateau from 2004 to 2010. The seasonal and inter-annual variability in gross primary productivity (GPP), net ecosystem exchange (NEE), evapotranspiration (ET), and water use efficiency (WUE) were examined and the main influencing factors were identified using the Pearson correlation. The results indicate that the seasonal GPP and NEE showed a bimodal distribution in WWE, while this was unimodal in AFE. The sinusoidal function did well in the characterization of seasonal ET dynamics for both ecosystems, with the determination coefficients being 0.85 and 0.94, respectively. In WWE and AFE, the annual mean GPP were 724.33 and 723.08 g C m⁻² a⁻¹, respectively, and the corresponding ET were 392.22 and 410.02 mm a⁻¹. However, the difference in NEE between the two ecosystems was obvious, NEE were −446.28 and −549.08 g C m⁻² a⁻¹, respectively, showing a stronger carbon sink in AFE. There were strong coupling relationships between the GPP and ET of both ecosystems; the overall slopes were 1.71 and 1.69, respectively. The seasonal trend of WUE was bimodal in WWE, with peak values of 3.94 and 3.65 g C kg⁻¹ H₂O, occurring in November and April, respectively. However, the monthly WUE in AFE had one single peak of 4.07 g C kg⁻¹ H₂O in January. Photosynthetically active radiation (PAR) and soil temperature (T_s) were most positively correlated with GPP, net radiation (R_n) and T_s were the major factors influencing ET, while vapor pressure deficit (VPD) and soil water content (SWC) were the major influencing factors for WUE. These results provide observational support for regional carbon neutrality simulations. Full article

Nearly 50 million km² of global land experiences seasonal transitions from predominantly frozen to thawed conditions, significantly impacting various ecosystems and hydrologic processes. In this study, we assessed the capability to retrieve surface freeze–thaw (FT) conditions using Sentinel-1 synthetic aperture radar (SAR) data time series at two agro-forested study sites, St-Marthe and St-Maurice, in southern Québec, Canada. In total, 18 plots were instrumented to monitor soil temperature and derive soil freezing probabilities at 2 and 10 cm depths during 2020–21 and 2021–22. Three change detection algorithms were tested: backscatter differences (∆σ) derived from thawed reference (Delta), the freeze–thaw index (FTI), and a newly developed exponential freeze–thaw algorithm (EFTA). Various probabilistic mixed models were compared to identify the model and predictor variables that best predicted soil freezing probability. VH polarization backscatter signals processed with the EFTA and used as predictors in a logistic model led to improved predictions of soil freezing probability at 2 cm (Pseudo-R² = 0.54) compared to other approaches. The EFTA could effectively address the limitations of the Delta algorithm caused by backscatter fluctuations in the shoulder seasons, resulting in more precise estimates of FT events. Furthermore, the inclusion of crop types as plot-level effects within the probabilistic model also slightly improved the soil freezing probability prediction at each monitored plot, with marginal and conditional R² values of 0.59 and 0.61, respectively. The model accurately classified observed binary ‘frozen’ or ‘thawed’ states with 85.2% accuracy. Strong cross-level interactions were also observed between crop types and the EFTA derived from VH backscatter, indicating that crop type modulated the backscatter response to soil freezing. This study represents the first application of the EFTA and a probabilistic approach to detect frozen soil conditions in agro-forested areas in southern Quebec, Canada. Full article

Global croplands, pastures, and human settlements have expanded in recent decades. This is accompanied by large increases in energy, water, and fertilizer consumption, along with considerable losses of biodiversity. In sub-Saharan Africa, policies are implemented without critical consideration; e.g., agricultural expansions impair ecosystem services. We studied land use/cover and the associated rate of change for four time epochs, i.e., 1991, 2001, 2011, and 2021. This employed remote sensing and GIS techniques for analysis, while future projections were modeled using cellular automata and the Markov chain. The kappa coefficient statistics were used to assess the accuracy of the final classified image, while reference images for accuracy assessment were developed based on ground truthing. Overall change between 1991 and 2021 showed that major percentage losses were experienced by water, forest, woodland, and wetland, which decreased by 8222 Ha (44.11%), 426,161 Ha (35.72%), 399,584 Ha (35.01%), and 105,186 Ha (34.82%), respectively. On the other hand, a percentage increase during the same period was experienced in cultivated land, built-up areas, and grasslands, which increased by 659,346 Ha (205.28%), 11,894 Ha (159.93%), and 33,547 Ha (98.47%), respectively. However, this expansion of thirsty sectors has not reversed the increasing amount of water discharged out of the Kilombero River catchment. We recommend the promotion of agroforests along with participatory law enforcement and capacity building of local communities’ institutions. Full article

Agroforestry systems (AFSs) have gained recognition as a land use strategy to address food security and climate change. They involve intentionally cultivating trees alongside crops and/or animals. AFSs cover approximately 5% of the global forest area and promote sustainable soil conservation, including soil organic carbon (C) sequestration (C_SEQ). In some areas of Chile, AFSs are used to preserve the ecological value of native forests. This study evaluates the effects of two AFSs, namely, an agroforest for fodder production (A_GROF_RST) and Silvopastoral (SPS), within a degraded native forest (Nothofagus obliqua sp.). The evaluation focuses on their impact on C_SEQ capacity and soil quality (SQ), using soil quality indexes (SQIs) derived from 30 soil quality indicators (SI_NDs) related to physical, chemical, and microbiological properties at two depths (0–5 and 5–20 cm). The results for the total depth analyzed (0–20 cm) indicate an average C_SEQ of 6.88 and 4.83 Mg C yr⁻¹ and a global SQI of 37.8% and 31.0% for A_GROF_RST and SPS, respectively. Among the thirteen SI_NDs that demonstrated significant differences (p < 0.05), five were associated with the considered depths (P⁺, Ca²⁺, S, ECEC, and Al_SAT), three differed between A_GROF_RST and SPS (BD, NH₄⁺, NO₃⁻), while SOC, K⁺, and Mg²⁺ varied across all conditions (e.g., combinations of systems and depths), and β-_GLU and N_MIN differed in a single condition. However, almost all 30 SI_NDs analyzed showed higher values at the 0–5 cm depth, indicating the positive effects of soil organic matter (SOM)/SOC additions. Significant interactions (Pearson’s correlation) revealed that SOC correlated with most SI_NDs (e.g., N, NH₄⁺, P⁺, K⁺, Ca²⁺, Mg²⁺, S, ECEC, N_MIN). These findings suggest that both A_GROF_RST and SPS systems have similar capabilities in restoring the ecological value of native Nothofagus forests while providing conditions for productive and complementary use. This sustainable option offers opportunities for cattle production alongside ecological restoration efforts and provides a possible strategy to generate public policies related to the ecosystem services of agroforestry systems. Full article

The purpose of the study is an economic assessment of the effectiveness of agroforestry based on determining the value of ecosystem services of an afforested model land object and extrapolating the data obtained to the territory of the south of the Volga upland with identical natural and economic conditions to the model. The study presents a methodology for the economic assessment of ecosystem goods and services of forested agricultural landscapes based on the modern classification of ecosystem services: CICES. It is established that the economic value of the regional ecosystem product provided by forested lands in the dry steppe is USD 1323 per 1 ha of agroforest landscape per year (price for 2021 on average for 30 years). Of these, regulatory and maintenance services account for 52% of the total economic value, security services—45%, and cultural services—3%. The projected economic value of ecosystem services that will be provided by afforested lands in the south of the Volga upland, the price for 2025, taking into account inflation, is estimated at almost USD 20 million. This value is a sufficient justification for conducting forest reclamation works in the region and providing recommendations for their necessity for small enterprises and farms. Full article

This study investigated the hydrological properties of litter in different vegetation cover types, including Eucalyptus sp. plantation, Agroforestry, and Restoration Forest. The research focused on evaluating litter accumulation, composition, water holding capacity, and effective water retention. The results revealed variations in litter accumulation among the stands, and especially Eucalyptus sp., which had a higher proportion of branches compared to leaves. The water holding capacity of the litter differed among the stands. Agroforest and Restoration Forest showed higher litter water capacities than Eucalyptus sp. The composition and decomposition stage of the litter fractions influenced their water retention capabilities, with leaves exhibiting superior water retention. In contrast, branches had lower water absorption due to their hydrophobic nature. Despite these differences, the effective water retention, which indicates the ability of litter to intercept precipitation, was similar among the stands. The findings highlight the importance of considering litter composition and species-specific characteristics in understanding the hydrological functions of litter. This knowledge contributes to effective conservation and management strategies for sustainable land use practices and water resource management. Further research is recommended to expand the study’s scope to include a wider range of forest types and natural field conditions, providing a more comprehensive understanding of litter hydrological functions and their implications for ecosystem processes. Full article

Soil compaction has become a global problem affecting soil worldwide. With an increased population, more demands for food and wood have resulted in intensive cultivation and increased mechanization of our farmlands and irrigated plantations. The use of heavy machinery results in soil compaction, which affects the entire soil ecosystem. This study was conducted to analyze the impact of compacted soil on germination and initial growth stages of four major agro-forest trees of central Punjab, Pakistan. Morpho-physiological traits of all selected species (Eucalyptus camaldulensis, Albizia lebbeck, Vachellia nilotica, and Zyziphus mauritiana) were measured against soil compaction. Results indicated that the root and shoot length, biomass, root–shoot ratio, diameter at root collar, no. of leaves and branches, leaf area, germination, and survival %, and physiological traits (i.e., photosynthetic rate, transpiration rate, stomatal conductance, internal CO₂ concentration, and photosynthetic water use efficiency) were significantly affected by the induced soil compaction. Eucalyptus camaldulensis Dehnh. performed better and exhibited 96% germination percentage under (1.40 mg m⁻³) compaction level and gradually decreased by 11% with the increase of compaction level (1.80 mg m⁻³). It shows that the shorter roots developed due to soil compaction decreased water use efficiency, photosynthesis, and whole-plant physiological performance. The findings concluded that judicious use of machinery is highly desired for sustainable and good-quality wood production from farm trees. Full article

Agroforest systems have been widely recognized as an integrated approach to sustainable land use for addressing the climate change problem because of their greater potential to sequester atmospheric CO₂ with multiple economic and ecological benefits. However, the nature and extent of the effects of an age-sequence of agroforestry systems on carbon (C) storage remain largely unknown. To reveal the influence of different aged poplar-crop systems on C stocks, we investigated the variation in biomass and C storage under four aged poplar-crop agroforest systems (3-, 9-, 13-, and 17-year-old) in the Henan province of China. The results showed that stand biomass increased with forest age, ranging from 26.9 to 121.6 t/ha in the corresponding four aged poplar-crop systems. The poplar tree biomass accounted for >80% of the total stand biomass in these poplar-crop agroforestry systems, except in the 3-year-old agroforestry system. The average stand productivity peaked in a 9-year-old poplar-crop system (11.8 t/ha/yr), the next was in 13- and 17-year-old agroforestry systems, and the minimum was found in 3-year-old poplar-crop stands (4.8 t/ha/yr). The total C stocks increased, with aging poplar-crop systems ranging from 99.7 to 189.2 t/ha in the studied agroforestry systems. The proportion of C stocks accounted for about 6, 25, and 69% of the total C stocks in the crop, poplar tree, and soil components in all studied agroforestry ecosystems, respectively. Our results suggested that the poplar-crop system, especially in productive and mature stages, is quite an effective agroforestry model to increase the study site’s biomass production and C stocks. This study highlighted the importance of agroforestry systems in C storage. It recommended the poplar-crop agroforest ecosystems as a viable option for sustainable production and C mitigation in the central region of China. Full article

The conversion of fertile croplands to Eucalyptus woodlots in Ethiopian highlands, due to its business attractiveness to smallholders, raises concerns related to food production, water resources, carbon and other ecosystem services. This study was therefore designed to examine land allocation and plantation management decisions. Our emphasis was on the analysis of tradeoffs between the economic gains obtained from harvesting Eucalyptus timber and food production, carbon and water use. For that purpose, we considered a 1987 ha agroforest landscape in the Amhara region, Northern Ethiopia. With a planning horizon covering nine one-year periods, we developed and used nine Model I single objective linear programming (LP) models, and analyzed tradeoffs between objectives (e.g., land expectation value (LEV), Carbon, volume of ending inventory (VolEI), crop production and water use) using an LP-based Pareto frontier approach. The study revealed that the objective of maximizing the total economic gain from the sale of Eucalyptus wood poles favored a complete conversion of the available cropland into Eucalyptus woodlots. To meet the minimum annual crop production/consumption/requirements of households in the study area, the land under Eucalyptus should be limited to 1772 ha, with a sequestration potential of 1.5 to 1.57 × 10⁷ kg yr⁻¹ of carbon in the aboveground biomass. However, this land cover limit should be decreased to 921 ha so as to limit the total annual water use (for biomass production) below the amount available from rainfall (11,000 m³ ha⁻¹ yr⁻¹). Moreover, the study highlighted that maximizing the harvested wood volume or LEV would come at the cost of a decreased aboveground carbon stock and volume of ending inventory and higher total water use. It also provided alternative optimal Pareto-front points, among which decision makers will be able to select their preferred targets. The current study also showed the potential for the application of Pareto frontier approaches to support the development of effective ecological/economic management strategies and the design of land use policies in an Ethiopian context. Full article

Suspended sediment is an important constituent of freshwater ecosystems that supports biogeochemical, geomorphological, and ecological processes. Current knowledge of suspended sediment is largely based on surface water studies; however, improved understanding of surface and in situ groundwater suspended sediment processes will improve pollutant loading estimates and watershed remediation strategies. A study was conducted in a representative mixed-use, agro-forested catchment of the Chesapeake Bay Watershed of the northeast, USA, utilizing an experimental watershed study design, including eight nested sub-catchments. Stream water and shallow groundwater grab samples were collected monthly from January 2020 to December 2020 (n = 192). Water samples were analyzed for suspended sediment using gravimetric (mg/L) and laser particle diffraction (µm) analytical methods. Results showed that shallow groundwater contained significantly higher (p < 0.001) total suspended solid concentrations and smaller particle sizes, relative to stream water. Differences were attributed to variability between sites in terms of soil composition, land use/land cover, and surficial geology, and also the shallow groundwater sampling method used. Results hold important implications for pollutant transport estimates and biogeochemical modeling in agro-forested watersheds. Continued work is needed to improve shallow groundwater suspended sediment characterization (i.e., mass and particle sizes) and the utility of this information for strategies that are designed to meet water quality goals. Full article

Plant functional traits are useful in tracking changes in the environment, and play an important role in determining ecosystem functioning. The relationship between plant functional traits and ecosystem functioning remains unclear, although there is growing evidence on this relationship. In this study, we tested whether the functional structure of vegetation has significant effects on the provision of ecosystem services. We analysed plant trait composition (specific leaf area, leaf carbon and nitrogen ratio, isotopic carbon fraction, stem dry matter content, seed mass and plant height), soil parameters (nutrients, pH, bulk density) and proxies of ecosystem services (carbon stock, decomposition rate, invertebrate activity) in twenty-four plots in three tropical ecosystems (active restored and natural forests and an agroforestry system) in Ghana. For each plot, we measured above-ground biomass, decomposition rates of leaves and invertebrate activity as proxies for the provision of ecosystem services to evaluate (i) whether there were differences in functional composition and soil properties and their magnitude between ecosystem types. We further aimed to (ii) determine whether the functional structure and/or soil parameters drove ecosystem functions and multifunctionality in the three ecosystem types. For functional composition, both the leaf economic spectrum and seed mass dimension clearly separated the ecosystem types. The natural forest was more dominated by acquisitive plants than the other two ecosystem types, while the non-natural forests (agroforest and restored forest) showed higher variation in the functional space. The natural forest had higher values of soil properties than the restored forest and the agroforestry system, with the differences between the restored and agroforestry systems driven by bulk density. Levels of ecosystem service proxies and multifunctionality were positively related to the functional richness of forest plots and were mainly explained by the differences in site conditions. Our study demonstrated the effects of functional forest structure on ecosystem services in different forest ecosystems located in the semi-deciduous forest zone of Ghana. Full article

Major objectives of this study were to produce low-emitting wood pellet biofuel from selected agro-forest tree species, i.e., Kikar (Acacia nilotica), Oak (Quercus semicarpifolia), and Mesquite (Prosopis juliflora), grown in the southern part of the Khyber Pakhtunkhwa (KP) province of Pakistan using indigenously developed technology (pelletizer machine). Primary raw material, such as sawdust of the selected agro-forest tree species, was obtained from sawmills located in southern part of KP. Life cycle inventory (LCI) was sourced for entire production chain of the wood pellet biofuel by measuring quantities of various inputs consumed and output produced. In addition, the wood pellets were characterized to examine diameter, length, moisture content, ash content, bulk density, high heating value (HHV), low heating value (LHV), as well as nitrogen and sulphur contents. A comprehensive life cycle assessment was performed for wood pellet biofuel production chain using SimaPro v9.1 software. A functional unit of one (01) kilogram (kg) wood pellet biofuel was applied following a gate-to-gate approach. The results of the present study were in accordance with the recommended Italian standard CTI-R $04/5$ except for pellet bulk density and nitrogen content. The bulk density for all wood pellets, manufactured from the saw dust of three different agro-forest tree species, were lower than the recommended Italian standard, while for nitrogen content, the results were higher than the recommended Italian standard. Among the environmental impacts, Kikar (Acacia nilotica) wood pellets were the major contributor to fossil fuel depletion, followed by ecotoxicity, mineral depletion and acidification/eutrophication. This was primarily due to lubricating oil and urea-formaldehyde (UF) resin used as inputs in the wood pellets biofuel manufacture. Likewise, human health and ecosystem quality was also affected by lubricating oil, UF resin, and saw dust, respectively. In cumulative exergy demand of 1 kg wood pellets biofuel, the highest impact was from Kikar wood pellets for non-renewable fossils, mainly due to lubricating oil used. Difference in environmental impacts, damage assessment, and exergy were examined in three different scenarios for major hotspot inputs by reducing 20% lubricating oil in case 1, 20% UF resin in case 2, and without usage of UF resin in case 3, while marked reduction was observed in ecotoxicity, fossil fuel, and mineral depletion, as well as acidification/eutrophication impact category. Moreover, a pronounced reduction was also noted in the non-renewable fossil fuel category of cumulative exergy demand of one kg of wood pellets biofuel produced. Full article

Using remotely sensed data to estimate the biophysical properties of vegetation in woodlands is a challenging task due to their heterogeneous nature. The objective of this study was to assess the biophysical parameters of different vegetation types (cork oak trees, shrubs and herbaceous vegetation) in cork oak woodland through the analysis of temporal trends in spectral vegetation indices (VIs). A seven-year database (from 2011 until 2017) of in situ observations collected with a field spectroradiometer with a monthly basis was used and four VIs were derived, considered as proxies for several biophysical properties of vegetation such as biomass (Normalized Difference Vegetation Index—NDVI); chlorophyll content (MERIS Terrestrial Chlorophyll Index-MTCI), tissue water content (Normalized Difference Water Index—NDWI) and the carotenoid/chlorophyll ratio (Photochemical Reflectance Index—PRI). During the analyzed period, some key meteorological data (precipitation, temperature, relative air humidity and global radiation) were collected for the study site, aggregated at three different time-lags (short period (30 d), medium period (90 d) and hydrological period (HIDR)), and their relationship with VIs was analyzed. The results showed different trends for each vegetation index and vegetation type. In NDVI and NDWI, herbaceous vegetation showed a highly marked seasonal trend, whereas for MTCI, it was the cork oak and Cistus salvifolius, and for PRI, it was Ulex airensis that showed the marked seasonal trend. Shrubs have large differences depending on the species: the shallow-rooted Cistus salvifolius showed a higher seasonal variability than the deep-rooted Ulex airensis. Our results revealed the importance of temperature and precipitation as the main climatic variables influencing VI variability in the four studied vegetation types. This study sets up the relationships between climate and vegetation indices for each vegetation type. Spectral vegetation indices are useful tools for assessing the impact of climate on vegetation, because using these makes it easier to monitor the amount of “greenness”, biomass and water stress of vegetation than assessing the photosynthetic efficiency. Proximal remote sensing measurements are fundamental for the correct use of remote sensing in monitoring complex agroforest ecosystems, largely used to inform policies to improve resilience to drought, particularly in the Mediterranean region. Full article