Enxeñaría Agroforestal

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Influence of turbine damping on OWC wave-to-wire performance
(Elsevier, 2026-04-01) López Moreira, Iván; Álvarez Fernández, Borja; Fouz, David Mateo; Carballo Sánchez, Rodrigo; Iglesias Rodríguez, José Gregorio; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
Turbine-chamber coupling is a decisive factor in the performance of oscillating water column (OWC) wave energy converters. In this study, a wave-to-wire model is developed to evaluate the influence of turbine-induced damping on the different energy conversion stages—pneumatic, mechanical, and electrical—of an OWC equipped with a biradial turbine. The methodology combines: (i) high-resolution spectral modelling to characterize the nearshore wave energy resources at a study site in Galicia (NW Spain); (ii) physical (laboratory) and computational fluid dynamics (CFD) modelling of the OWC hydrodynamics accounting for air compressibility; and (iii) analytical modelling of the turbine–generator set, including a control law for rotational speed regulation. Results show that turbine-induced damping critically affects the performance of OWC devices across all energy conversion stages, with the optimal damping condition varying according to the stage considered. Mechanical efficiency emerges as a key factor, which can shift the optimal damping towards higher values than those indicated by the pneumatic efficiency alone. These findings underscore the importance of turbine efficiency in OWC design and highlight the need to integrate mechanical and electrical conversion stages into turbine-chamber coupling strategies to achieve optimal performance.
Application of artificial neural networks for characterizing the hydrodynamic performance of oscillating water column devices
(Elsevier, 2026-07-01) Álvarez Fernández, Borja; Fouz, David Mateo; López Moreira, Iván; Carballo Sánchez, Rodrigo; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
This work investigates the application of artificial neural networks to improve the characterization and assist in the optimization process of oscillating water column wave energy converters, thus increasing the reliability and accuracy of performance predictions. More specifically, this work addresses the challenges associated with resource-intensive physical modelling by combining neural networks with specifically designed experimental campaigns, thereby reducing the dependency on exhaustive experimental testing while maintaining predictive accuracy. The methodology integrates multilayer perceptron networks with Levenberg-Marquardt training, selected for their robustness and suitability for regression tasks. Key parameters, including significant wave height, energy period, and turbine-induced damping, are used as inputs to predict accurate performance in terms of capture-width ratio. Among the tested configurations, a network with a single hidden layer of 20 neurons demonstrated the best balance between accuracy and generalization, achieving a root mean square error below 2.5% and a correlation coefficient very close to unity (R > 0.99) when validated against experimental data. The selected neural network model is subsequently applied to analyse the performance of an oscillating water column device operating at a case study site, accurately predicting its capture-width ratio matrix for untested turbine-induced damping values and enabling the identification of the optimum damping through a parametric search. The findings confirm that artificial neural network based frameworks are a valuable tool that can provide information which streamline the design and help the optimization process of oscillating water column devices.
Spectral Variability Analysis of Lupinus mutabilis Sweet Under Nanofertilizer and Chelate Application Through Spectroscopy and Unmanned Aerial Vehicle (UAV) Multispectral Images
(MDPI, 2025-02-14) Sinde-González, Izar; Murgueitio-Herrera, Erika; Falconí, César E.; Gil Docampo, María de la Luz; Toulkeridis, Theofilos; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
Lupin is an Andean legume that has gained importance in Ecuador due to the protein content in its grain. Nonetheless, in recent times the production of lupin has been affected by inadequate nutritional management. In order to avoid such circumstances, the current study spectrally analyzed lupin cultivation under the application of nanofertilizers and Fe and Zn chelates, within two controlled trials, using a radiometer spectrum, an active crop sensor and a multispectral sensor mounted on a UAV. Vegetation indices were generated and subsequently statistically analyzed using ANOVA and Tukey tests. In the field trial, the treatments lacked an indication of significant improvements, while in the greenhouse trial, the nanofertilizer treatments indicated better results compared to the control treatments. However, it was also determined that the application of nanofertilizers at a concentration of 540 ppm demonstrated significant efficiency in greenhouse conditions, which could not be achieved in the field. Furthermore, the chelate treatment presented a certain degree of toxicity for the plant.
Life Cycle Assessment of Red Grape Production in La Rioja Designation of Origin
(2024-10-30) Agraso Otero, Adrián; Cancela Barrio, Javier José; Vilanova de la Torre, Mar; Ugarte Andreva, Javier; Rebolledo Leiva, Ricardo; González García, Sara; Universidade de Santiago de Compostela. Centro Interdisciplinar de Investigación en Tecnoloxías Ambientais (CRETUS); Universidade de Santiago de Compostela. Departamento de Enxeñaría Química; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
Assessing environmental impacts and ecosystem services of Hops crop in Galicia, NW Spain: critical contributors for sustainable cultivation strategies
(Springer, 2026-03-17) Agraso Otero, Adrián; Cancela Barrio, Javier José; Fandiño Beiro, María; Rebolledo Leiva, Ricardo; González García, Sara; Universidade de Santiago de Compostela. Centro Interdisciplinar de Investigación en Tecnoloxías Ambientais (CRETUS); Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal; Universidade de Santiago de Compostela. Departamento de Enxeñaría Química
Hops (Humulus lupulus) is a crop of great interest due to its use in the brewing industry; however, the environmental impacts associated with its cultivation remain largely unexplored. Therefore, this study provides the first evaluation of the environmental performance of hops cultivation using the Life Cycle Assessment methodology, with a case study of Galicia, NW Spain. The system boundaries, following a cradle-to-farm-gate approach, included all field operations throughout its entire lifespan (20 years), with primary data obtained directly from farmers. Impact categories such as Global Warming, Eutrophication, Ecotoxicity and Water Scarcity were considered. The main environmental hotspots identified were irrigation, due to the high crop water requirements, followed by agrochemical production and the associated on-field emissions. The results showed impacts of 3.05 kg CO₂ eq in global warming, 35.35 g SO₂ eq in terrestrial acidification or 70.3 m3 in water scarcity per kilogram of dry hop cones. Agricultural activities exert pressure on our natural ecosystems in different ways, for example, globally through the propagation of emissions or locally through the degradation of species-rich landscapes, with plants being the most affected taxon in this case. Moreover, two ecosystem services were assessed: pollination and soil erosion. Pollinator presence was found to be constant throughout spring and summer, with a ratio close to 50% of the regional maximum, while the effects of soil erosion control were estimated at €838 over the 20-year lifespan of the crop. With these results, the environmental performance of hop cultivation can be significantly improved, paving the way for more sustainable products within the brewing industry.
Parámetros volumétricos y de biomasa en una hectárea de sabana en Planaltina de Goiás, Brasil
(Editorial Tecnológica de Costa Rica, 2025) Imaña-Encinas, José; Riesco Muñoz, Guillermo; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
Se estudió la vegetación arbórea sobre una hectárea representativa de la sabana en sentido estricto y situada en Planaltina, Estado de Goiás (Brasil). En la zona de estudio se contabilizaron 490 árboles con diámetro normal igual o superior a 5 cm. Se obtuvo el diámetro medio, la espesura (en número de pies por hectárea y en área basimétrica), el volumen de madera en verde con corteza y el peso seco de la madera, para toda la masa forestal y para cada una de las 51 especies arbóreas presentes. La espesura resultó ser inferior a la existente en formaciones forestales análogas, con una presencia destacada de las clases diamétricas inferiores (diámetro normal inferior a 13 cm), lo que sugiere que el área protegida analizada fue objeto de aprovechamientos forestales. Las existencias maderables obtenidas fueron 16 m³/ha, correspondientes a 11.927 kg/ha de biomasa leñosa seca. El 67 % de las existencias (en volumen y en peso) correspondía a fustes y el resto a ramas. La mayor parte del volumen de fustes (56 %) y la mayor parte de la biomasa (61 %) procedía de siete especies: Hymenaea stigonocarpa, Qualea parviflora, Guapira nixia, Caryocar brasiliense, Sclerolobium paniculatum, Pouteria ramiflora y Pterodon polygalaeflorus.
La regularidad en la anchura de anillos de crecimiento y su empleo en la clasificación visual de la madera para su asignación al sistema Europeo de clases resistentes
(Universidad del Bío-Bío, 2024-11-12) Riesco Muñoz, Guillermo; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
The homogeneity of wood growth ring width is associated with greater rigidity and mechanical strength of the material. Therefore, understanding ring width homogeneity would be useful for visually grading sawn wood for structural applications. However, the effect of homogeneity on mechanical performance of wood has not been quantified. In this study, the dispersion of the ring width was analyzed to assess its predictive value for elasticity and axial bending strength in Quercus robur (european oak) wood beams. To carry out the study, 26 adult oak trees were felled in Galicia (northwestern Spain). The stems obtained were cut and sawn to produce planks, which were air-dried and subsequently planned to produce beams with target dimensions 2000 mm × 100 mm × 50 mm. For a sample of 52 of these beams, we measured the axial bending strength, the elastic modulus in axial bending, the wood density and moisture content, as well as the percentage of sapwood and the width of each growth ring in the cross section. The descriptive variables of the ring homogeneity, calculated using data from all rings in each beam (standard deviation, variance, interquartile range), were more closely related to mechanical properties. Beams with more homogeneous rings exhibited significantly higher elastic modulus and axial bending strength, with the strongest correlation observed between ring width variance and axial bending elastic modulus (R = -0,41**). However, the correlations observed do not justify developing a predictive model for elasticity or mechanical strength based solely on ring width homogeneity, although me-chanical behavior is significantly influenced by ring homogeneity. Consequently, this characteristic could be incorporated into visual strength grading standards for oak wood.
Spectroscopic analysis (UV-VIS-NIR) for predictive modeling of macro and micronutrients in grapevine leaves
(Elsevier, 2025-02-01) Manzano, Jose Ignacio; Rodríguez Febereiro, Marta; Fandiño Beiro, María; Vilanova de la Torre, Mar; Cancela Barrio, Javier José; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
Assessing nutrient concentrations in grapevines is crucial not only for the overall physiology of the plant but also for the quality of the resulting wine. Accurate determinations are also relevant for enhancing nutrient use efficiency and formulating fertilizer recommendations. Hence, there is a considerable demand for a swift technique to analyze vine organs. Diffuse reflectance spectroscopy coupled with chemometric methods emerges as a potent, cost-effective, and environmentally friendly analytical technique for determining nutrient concentrations in plants. The objective of this study is to ascertain the viability of wide range spectrum (190–2600 nm) spectroscopy in providing precise insights into the nutritional status of vines. Our investigation specifically targets on the determination of C, N, P, K, Ca, Mg, B, Cu, Fe, Mn, Zn, Na, and Al in vine leaves from different wine growing areas, varieties and harvest years. Partial Least Squares Regression (PLS-R) was employed to construct models for the concentrations of these nutrients based on the reflectance measurements of the leaves. The model was trained using 70 % of the samples, while the remaining 30 % constituted the independent validation. Results from the validation set indicated accurate validation for most nutrients, with determination coefficients (r2) of 0.70 for C, 0.72 for N, 0.64 for P, 0.75 for K, 0.84 for Ca, 0.48 for Mg, 0.45 for B, 0.58 for Cu, 0.26 for Fe, 0.82 for Mn, 0.50 for Zn, 0.90 for Na, and 0.69 for Al. The findings revealed that reflectances in the visible (VIS) region of the spectrum played a key role in predicting micronutrients like B, corresponding with photosynthetic pigments (chlorophylls and carotenoids). In contrast, reflectances in the near-infrared region (NIR) had a greater impact on macronutrient prediction, particularly for P and Mg, due to their stronger interaction with organic compounds. The ultraviolet (UV) range played a minor role, highlighting the predominant importance of the VIS-NIR regions in spectroscopic analyses. Finally, the results support the potential of this technique for swiftly and non-invasively predicting both macro and micronutrient levels in grapevine plants, and facilitate the fertilization planning using variety-specific reference levels, or precision viticulture adapted to site-specific demands, including spatial intra-plot variability.
Prediction of carbon dioxide concentration in weaned piglet buildings by wavelet neural network models
(Elsevier, 2017-11-03) Besteiro, Roberto; Arango López, Tamara; Ortega Martínez, Juan Antonio; Rodríguez Rodríguez, Manuel Ramiro; Fernández Rodríguez, María Dolores; Velo Sabín, Ramón; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal; Universidade de Santiago de Compostela. Departamento de Anatomía, Produción Animal e Ciencias Clínicas Veterinarias
Carbon dioxide concentration is a major factor in air quality, animal welfare and air exchange rates inside livestock buildings. CO2 concentration series show a dynamic, non-linear and non-stationary behavior. This type of process can be handled by Wavelet Neural Network (WNN) models, which have been developed in recent years. The purpose of this paper is to develop WNN models capable of predicting the dynamics of CO2 in weaner buildings. Outdoor temperatures, CO2 concentration and temperature in the animal zone and animal activity were recorded in a commercial piglet farm during two complete production cycles. Two WNN models were generated from the recorded data: an autoregressive model (AM) that used the CO2 series and outdoor temperatures for the prediction, and an explanatory model (EM) that used only exogenous variables, namely outdoor temperature, temperature in the animal zone and animal activity. Because CO2 is a highly autoregressive variable, the best results are obtained with the AM. The AM yield an RMSE of 26.330 ppm and a Pearson’s r of 0.995. The EM, with an RMSE of 154.361 ppm and a Pearson’s r of 0.895, reveal the importance of indoor and outdoor temperatures and, consequently, of ventilation rate, for CO2 concentration inside the building. In addition, our results show the effects of animal activity on CO2 concentration, which are delayed by 40–50 min. Based on these results, the CO2 concentrations in the animal zone of weaner buildings can be accurately predicted by WNN models. Therefore, WNN modeling could be widely used to predict and understand the dynamics of environmental variables inside livestock buildings
Power performance assessment of vertical-axis tidal turbines using an experimental test rig
(MDPI, 2021-10-15) Fernández Jiménez, Aitor; Álvarez Álvarez, Eduardo; López Gallego, Mario; Fouz, David Mateo; López Moreira, Iván; Gharib-Yosry, Ahmed; Claus Gómez, Rubén; Carballo Sánchez, Rodrigo; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal; Universidade de Santiago de Compostela. Departamento de Produción Vexetal e Proxectos de Enxeñaría
This article presents the characteristic curves of a vertical-axis hydrokinetic tidal turbine of the Darrieus subtype aimed at meeting the electricity demand of port facilities located at harbors and estuaries with low water-speed conditions. The turbine was tested in the water-current flume of the University of Santiago de Compostela for several flow conditions with different water heights and water speeds. Blockage conditions were tested by examining the results from two groups of tests: with and without an accelerator device that restricts the flow around the rotor. The tip speed ratio and the power coefficient were used to characterize the performance of the turbine for each test. Finally, the results for open-field conditions were obtained by applying empirical expressions, which allowed us to assess the performance of the device in estuaries and harbors with known water-flow regimes
Design selection and geometry in OWC wave energy converters for performance
(MDPI, 2021-03-19) López Moreira, Iván; Carballo Sánchez, Rodrigo; Fouz, David Mateo; Iglesias Rodríguez, José Gregorio; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal; Universidade de Santiago de Compostela. Departamento de Produción Vexetal e Proxectos de Enxeñaría
Although oscillating water column (OWC) wave energy converters are arguably one of the most studied technologies, it is not clear which chamber geometry, among all of the available alternatives, would provide the best performance at a site of interest. In this work, a numerical model based on the Navier-Stokes equations for two compressible fluids, using a volume-of-fluid interface-capturing approach, is implemented to determine the best performing OWC geometry in a case study off the Port of Vigo (NW Spain). Four general shapes of OWC are analyzed: classic, stepped-bottom, U-shaped and L-shaped, and geometrical variants are investigated. In total, 18 chamber geometries are studied, considering the same turbine geometry in all of them. It was found that the U-shaped and L-shaped designs are the most easily tuned to resonate at a period of interest. Of these two, the L-shaped performs better. The best performance is achieved for an L-shaped OWC design with a shallow entrance, a high horizontal chamber duct and a wide vertical duct, for which a maximum capture-width ratio of 71.6% was achieved.
Effects of tidal stream energy exploitation on estuarine circulation and its seasonal variability
(MDPI, 2022-10-20) Sánchez Carricoba, Marcos; Fouz, David Mateo; López Moreira, Iván; Carballo Sánchez, Rodrigo; Iglesias Rodríguez, José Gregorio; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal; Universidade de Santiago de Compostela. Departamento de Produción Vexetal e Proxectos de Enxeñaría
Residual flows are of major importance in coastal areas, driving environmental processes such as sediment transport or nutrient dispersion. Consequently, in those areas where a large tidal stream energy resource is available, prior to the installation of a tidal farm, it is imperative to assess how energy extraction affects the residual flows and, in particular, upwelling events. In this paper, the potential effects of different configurations of tidal stream farms on the residual circulation and its seasonality are analysed by means of a case study: Ria de Ortigueira, the westernmost of the Galician Rias Altas (NW Spain). For this purpose, a 3D numerical model was implemented and validated against field measurements. Next, a total of eight case studies, including the operation of bottom-fixed and floating converters under typical summer and winter scenarios, considering upwelling favourable winds, were studied. Overall, when a tidal farm operates, regardless of its configuration and the forcings considered, the resulting general residual flow pattern does not experience significant modifications. This pattern is characterized by a 2D circulation in the inner ria and a positive estuarine circulation in the middle and outer ria. The largest modifications of the residual flow are apparent in the vicinities of the plant, with maximum values of about 0.05 ms−1. Outside this area, the alteration is lower than 0.01 ms−1 and virtually negligible at some distance from the farm where upwelling events develop
Improvements in the design of nest cavities to attract cephalopods and crustaceans in a green artificial reef unit according to tridimensional hydrodynamic criteria – Application to the Ares-Betanzos estuary
(Elsevier, 2023-10-09) Carral Couce, Luis Manuel; Lamas Galdo, María Isabel; Fouz, David Mateo; López Moreira, Iván; Carballo Sánchez, Rodrigo; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal; Universidade de Santiago de Compostela. Departamento de Produción Vexetal e Proxectos de Enxeñaría
Installing artificial reefs (ARs) on the seabed creates a hard substrate that alters water flow and causes different species to settle. For this reason, by applying hydrodynamics to ARs, a useful tool is created for analysing these reefs so that there is adequate nutrient circulation and a propitious habitat for benthic and pelagic fauna. Using hydrodynamic criteria to characterise the velocity field, the present work aims to propose a methodology for positioning nest cavities within an AR unit in which different species will settle. Biological considerations, such as nutrient supply as well as the most suitable size and shape for the nest cavities, are taken into account. A stateof- the-art 3D shallow water model is validated and applied to the Ares-Betanzos estuary (NW Spain), where the installation of an AR group has recently been proposed. This coastal body, with a complex 3D hydrodynamic structure, was achieved under representative average conditions in absence of winds, which in turn greatly differs both in space and time throughout a spring-neap tidal cycle. A 3D CFD (Computational Fluid Dynamics) tool is applied to model food delivery on the AR. Moreover, the optimal geometry and position of nest cavities are established through a created indicator, ARnest cavity position, in order to provide sufficient nutrient circulation. It was found that the most appropriate shape for the nest cavities is cylindrical and a diameter of 200–300 mm is the most appropriate size. In terms of the ideal positions for the nest cavities, these depend on the orientation of the AR with respect to the current velocity. One of the orientations analysed leads to sufficient nutrient supply to the whole AR, while the other orientation analysed leads to sufficient nutrient supply to the high and mid positions at the front face, mid and low positions at the back face and all positions along the lateral faces
Floating solar photovoltaic energy for coastal areas: A siting methodology
(Elsevier, 2025-10-15) Fouz, David Mateo; Carballo Sánchez, Rodrigo; López Moreira, Iván; Álvarez Fernández, Borja; Iglesias Rodríguez, Gregorio; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
The decision-making process at the early stages of marine renewable energy projects typically faces considerable uncertainties. Amongst them, identifying the most suitable cost-effective locations is a key aspect, for which several novel indices have been proposed recently. In the case of floating solar photovoltaic (FPV) energy, a nascent technology, efforts have focused on offshore sites, possibly to the detriment of nearshore options of high interest such as estuaries. Granted, coastal areas present specific challenges, not least their high environmental value and the coexistence of many uses of the marine space, the compatibility of which ought to be accurately assessed. In this work, the Integrated Floating Solar Energy (IFSE) index is proposed for siting FPV farms in coastal areas. This novel index is based on a comprehensive methodology, which considers the aspects relevant to the decision-making process: (i) the exploitable resource, (ii) the costs of installation, and (iii) the socioeconomic and environmental aspects. The IFSE index is applied to a case study in the Ría de Vigo, an estuary in NW Spain, leading to the delimitation of an area of about 7 km2 as that with the highest interest, and showing the capability of this index to significantly contribute to the decision-making process for the deployment of FPV farms in coastal areas.
Optimization of the Yacovino maneuver for superior canal BPPV using numerical simulations
(Elsevier, 2025-07-22) Arán Tapia, Ismael; Bastos Costas, Guillermo; Pérez Muñuzuri, Alberto; Universidade de Santiago de Compostela. Centro Interdisciplinar de Investigación en Tecnoloxías Ambientais (CRETUS); Universidade de Santiago de Compostela. Departamento de Física de Partículas; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
We evaluated the effectiveness of the original Yacovino maneuver (YM) for treating superior canal benign paroxysmal positional vertigo (SC-BPPV) using numerical simulations and proposed modifications to enhance its efficacy. A high-resolution three-dimensional micro-computed tomography (μCT) reconstruction of a human membranous labyrinth was used to simulate the BPPV condition. Endolymphatic fluid dynamics were modeled by solving the Navier–Stokes equations, and otoconia of varying sizes (3–30 µm) were introduced as Lagrangian particles. Their displacement was tracked using a superior canal-centric polar coordinate system. Two maneuver protocols were simulated: the original YM and a modified version with adjusted rotational angles and a 30-second resting interval per step. The original YM resulted in otoconia trapping in the ampulla and canal switching, limiting its effectiveness. In contrast, the modified YM—in which the patient lies face down with a 50° head flexion in the initial step, followed by optimized subsequent rotations—significantly improved otoconia migration toward the utricular macula. Longer resting times further enhanced the displacement of smaller particles without compromising maneuver safety. These findings suggest that the modified YM is a safe and effective alternative for SC-BPPV treatment. Tailoring rotation angles based on anatomical variability may improve outcomes, though clinical validation is still required.
Use of national forest inventory data to develop stand density driven models for understorey shrubs and overstorey fuel variables and associated temporal dynamics in commercial plantations
(Elsevier, 2024-02-01) Castedo Dorado, Fernando; Ruiz González, Ana Daría; Vega Hidalgo, José Antonio; Arellano Pérez, Stéfano; Álvarez González, Juan Gabriel; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
Biomass tends to accumulate both in overstorey and understorey layers of forests growing in productive areas. The rapid growth of forest plantations established in productive areas can thus also lead to the creation of fire-prone landscapes. In this study, we assessed the extent to which overstorey stand density determines current values of the fine shrub fuel load (Wshr_G1) in the understorey and also two major canopy fuel characteristics related to crown fire activity -canopy base height (CBH) and canopy bulk density (CBD)- and the temporal dynamics of these. For this purpose, we developed two types of models for the three fuel complex variables: i) extreme response models, to define the upper limit of Wshr_G1 and CBD and the lower limit of CBH, the values of which may depend on stand density; and ii) dynamic models, to estimate the probability of increasing fuel loads and rate of change when a more hazardous situation is predicted. Data were obtained from 8087 plots, measured in the third, fourth and fifth Spanish National Forest Inventories, in plantations dominated by the major commercial species in northern Spain (Pinus pinaster, Pinus radiata, Pinus sylvestris and Eucalyptus globulus). The extreme response models generally explain more than 60% of the observed variability in the three fuel complex variables. According to these models, maximum shrub fuel load and CBD and minimum CBH in stands of the four tree species were limited by stand basal area, with different responses by different species. The dynamics of the fuel complex variables were determined by canopy cover, estimated as a proxy for stand density. The use of a two-step regression approach enabled realistic modelling of the dynamics of the fuel complex variables, allowing for a decrease in the shrub fuel biomass and in CBD between two time points. The dynamic models developed are age-independent and are therefore useful for practical applications because they can be applied to any stand without the need to know the stand age. Overall, the study findings provide insights into the complex relationship between both understorey and overstorey fuels and stand density in commercial plantations. As assessment of forest fuel complex variables is a prerequisite for most fire management activities, the study findings have important implications for forest and fuel management and planning in the region.
Mid-term effects of a thin-only treatment on fuel complex, potential fire behaviour and severity and post-fire soil erosion protection in fast-growing pine plantations
(Elsevier, 2020-03-15) Arellano Pérez, Stéfano; Castedo Dorado, Fernando; Álvarez González, Juan Gabriel; Alonso Rego, Cecilia; Vega, José Antonio; Ruiz González, Ana Daría; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
Fuel hazard reduction is an essential component of pine plantation management. In NW Spain, plantation managers assume that thin-only reduces the potential fire behavior and effects by decreasing the quantity and continuity of canopy fuels. Nevertheless, thin-only can alter additional variables than control fire behavior and effects such as surface fuel availability and microclimate conditions. Moreover, the duration of thinning effects could vary and be species-specific. We present an approach linking field-measured fuel variables to well-established models for assessing the mid-term effects (six years) of thin-only on potential fire behaviour and severity and ability of burned stands to protect soil against erosion. Field variables were obtained from 41 thinning trials installed in stands of P. pinaster (22 locations) and P. radiata (19 locations). Canopy fuel load and canopy bulk density were still significantly lower in treated sample plots for both species six years after treatments, whereas total and fine understory fuel loads were slightly but significantly larger in thinned plots in P. pinaster. In a simulation process, different fire danger scenarios were considered through two fire-related weather variables: the 10-m open wind speed and the fine dead fuel moisture content. Results showed that thin-only could significantly reduce the likelihood of active crown fire and its rate of spread for both species, particularly in P. pinaster, while passive crown fire probability increased. The potential fire severity, in terms of crown scorch height, scorch volume and tree mortality, hardly worsened by thinning. For fireline intensities lower than 4000 kW m−1, dead fuel moisture content effect on fire severity surpassed the wind speed influence. Moreover, protection of soil against erosion improved only slightly when thinning was previously carried out. The results of the study reveal that, in the mid-term, it is unlikely that thin-only, without intervention in the surface fuels, may have a marked influence on the reduction of the severity of a subsequent fire. The results also highlight the need of a comprehensive assessment of the effects of thin-only on both the whole fuel complex and microclimatic variables for obtaining realistic results.
Developing a site index model for P. Pinaster stands in NW Spain by combining bi-temporal ALS data and environmental data
(Elsevier, 2021-02-01) Guerra Hernández, Juan; Arellano Pérez, Stéfano; González Ferreiro, Eduardo; Pascual, Adrián; Sandoval Altelarrea, Vicente; Ruiz González, Ana Daría; Álvarez González, Juan Gabriel; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
Site index (SI) is a common measure of forest site productivity, serving as a valuable baseline for forest management. The main objective of this study was to develop a SI model for Pinus pinaster Ait. in north-west Spain by combining bi–temporal, low–density airborne laser scanning (ALS) data (acquired in the periods 2009–2011 and 2015–2017) with climatic, edaphic and physiographical data. Site productivity, assessed by site quality curves, was modelled using an age-independent difference equation method based on ALS metrics and environmental variables. For the model development process, we used data from 156 sample plots in pure and even-aged P. pinaster stands distributed throughout Galicia (NW Spain) and measured in the Spanish National Forest Inventory (SNFI). The generalized algebraic difference approach (GADA) formulation was tested by using two different base equations for modelling the dominant height growth (ΔH) from ALS variables. The GADA formulation derived from the Bertalanffy’s base model produced the best estimates of dominant height (H) for P. pinaster stands in Galicia. Use of the proposed model to estimate ΔH for a new pine stand requires two ALS data sets for estimating site-specific (local) parameters. To enable use of the model when such information is not available, the relationship between the values of the site-specific parameter and environmental variables was described using Multivariate Adaptive Regression Splines (MARS). Use of the MARS equation enabled us to develop spatially-explicit predictive maps of the site-specific parameter values, which can be used together with the GADA model to derive ΔH curves and SI estimates for P. pinaster stands in the whole study region.
Site Quality Models and Fuel Load Dynamic Equation Systems Disaggregated by Size Fractions and Vegetative States in Gorse and High Heath Shrublands in Galicia (NW Spain)
(MDPI, 2024-04-09) Vega, José Antonio; Álvarez González, Juan Gabriel; Arellano Pérez, Stéfano; Fernández, Cristina; Ruiz González, Ana Daría; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
Compatible model systems were developed for estimating fuel load dynamics in Ulex europaeus (gorse) and in Erica australis (Spanish heath) dominated shrub communities at stand level. The models were based on intensive, detailed destructive field sampling and were fitted simultaneously to fulfill the additivity principle. The models enable, for the first time, estimation of the biomass dynamics of the total shrub layer, size fractions and vegetative stage, with reasonably good accuracy. The approach used addresses the high variability in shrub biomass estimates by using a site index (SI) based on biomass levels at a reference age of 10 years. Analysis of the effect of climatic variables on site index confirmed the preference of gorse for mild temperatures and the ability of high heath communities to tolerate a wider range of temperatures. In the gorse communities, SI tended to increase as summer rainfall and the mean temperature of the coldest month increased. However, in the heath communities, no relationships were observed between SI and any of the climatic variables analyzed. The study findings may be useful for assessing and monitoring fuel hazards, updating fuel mapping, planning and implementing fuel reduction treatments and predicting fire behavior, among other important ecological and biomass use-related applications.
Where Do Fires Burn More Intensely? Modeling and Mapping Maximum MODIS Fire Radiative Power from Aboveground Biomass by Fuel Type in Mexico
(MDPI, 2025-01-29) Tinoco-Orozco, Diana Aime; Vega Nieva, Daniel José; Briseño Reyes, Jaime; Dominguez-Amaya, Mesías Edwin; Silva-Cardoza, Adrián Israel; Briones Herrera, Carlos Iván; Álvarez González, Juan Gabriel; Corral Rivas, José Javier; López Serrano, Pablito Marcelo; Jardel Pelaez, Enrique; Pérez Salicrup, Diego; Ruiz González, Ana Daría; Universidade de Santiago de Compostela. Departamento de Enxeñaría Agroforestal
Mapping potential fire intensity is a fundamental tool for fire management planning. Despite the wide use of Fire Radiative Power (FRP) as an indicator of expected fire intensity and fire emissions, very few studies have spatially analyzed the role of remotely sensed proxies of vegetation productivity to explain FRP. The current study aimed at modeling and mapping the relationships between aboveground biomass and Moderate Resolution Imaging Spectroradiometer (MODIS) maximum FRP, at 1 km pixel, in 2011–2020, for each of 46 fuel regions in the entirety of Mexico. Maximum FRP–biomass relationships supported a novel hypothesis of varying constraints of fire intensity. In lower-productivity areas, such as semiarid shrub- and grass-dominated ecosystems, fine fuel loads limited fire occurrence and FRP was positively related to biomass. In the more productive areas, such as temperate or tropical forests, a humped relationship of FRP against biomass was observed, suggesting an intermediate-productivity hypothesis of maximum fire intensity within those regions. In those areas, the highest fire intensity was observed in the intermediate biomass areas, where surface (timber understory) and crown fuel availability, together with higher wind penetration, can result in crown fires. On the contrary, within the most productive areas, the lowest intensity occurred, likely due to weather and fuel (timber litter) limitations.

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