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The Mediterranean Basin has experienced substantial land use changes as traditional agriculture decreased and population migrated from rural to urban areas, which have resulted in a large forest cover increase. The combination of Landsat time series, providing spectral information, with lidar, offering three-dimensional insights, has emerged as a viable option for the large-scale cartography of forest structural attributes across large time spans. Here we develop and test a comprehensive framework to map forest above ground biomass, canopy cover and forest height in two regions spanning the most representative biomes in the peninsular Spain, Mediterranean (Madrid region) and temperate (Basque Country). As reference, we used lidar-based direct estimates of stand height and forest canopy cover. The reference biomass and volume were predicted from lidar metrics. Landsat time series predictors included annual temporal profiles of band reflectance and vegetation indices for the 1985-2023 period. Additional predictor variables including synthetic aperture radar, disturbance history, topography and forest type were also evaluated to optimize forest structural attributes retrieval. The estimates were independently validated at two temporal scales, i) the year of model calibration and ii) the year of the second lidar survey. The final models used as predictor variables only Landsat based metrics and topographic information, as the available SAR time-series were relatively short (1991-2011) and disturbance information did not decrease the estimation error. Model accuracies were higher in the Mediterranean forests when compared to the temperate forests (R 2  = 0.6-0.8 vs. 0.4-0.5). Between the first (1985-1989) and the last (2020-2023) decades of the monitoring period the average forest cover increased from 21 ± 2% to 32 ± 1%, mean height increased from 6.6 ± 0.43 m to 7.9 ± 0.18 m and the mean biomass from 31.9 ± 3.6 t ha -1 to 50.4 ± 1 t ha -1 for the Mediterranean forests. In temperate forests, the average canopy cover increased from 55 ± 4% to 59 ± 3%, mean height increased from 15.8 ± 0.77 m to 17.3 ± 0.21m, while the growing stock volume increased from 137.8 ± 8.2 to 151.5 ± 3.8 m 3  ha -1 . Our results suggest that multispectral data can be successfully linked with lidar to provide continuous information on forest height, cover, and biomass trends., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Climate change is affecting both the frequency and scale of wildfires, as well as the increase in the number of days with Saharan dust intrusions. Traditionally, studies have focused on the extent to which the increase in fine particulate matter (PM) has had an impact on cardio-respiratory diseases, but (apart from PM) not on how the meteorological and pollution conditions in these situations affect other diseases, such as those linked to mental health. This study therefore sought to ascertain how daily mean PM 10 , PM 2.5 , NO 2 , O 3 concentrations and daily maximum temperature in heat waves influence daily emergency hospital admissions in Spain caused by mental and behavioural disorders, depression and anxiety on days with PM from biomass combustion and/or Saharan dust intrusions, as compared to days without such conditions, across the period 2009-2018. Our results indicate that on days on which there is biomass combustion, PM concentrations have a statistically significant effect on emergency admissions due to mental disorders, probably related with the toxicity of these particles. Yet on days with intrusions of Saharan dust rather than PM, it is the other variables considered in the analysis that are most closely linked to these types of admissions. The results of this study thus point to the need to implement public health prevention plans which take into account the joint effect of various environmental risk factors that act synergistically in given situations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This paper shows a practice to raise the reliability of an electric power system by the installation of distributed generation, taking gasified biomass as fuel. To calculate the reliability index, a probabilistic load flow was used. This index is determined as the fault probability of the system. The resolution of this probabilistic load flow combines the method of cumulants and Gram–Charlier expansion. To achieve the reliability index, simulating a number of contingencies is required; the greater the number of simulated contingencies, the higher the accuracy of the index obtained. This probabilistic technique uses the random variables as starting information, so the two generators and loads are simulated as random variables. The generators of this distributed generation are biomass-fueled gas engines, commonly found in Spain. The simulations carried out on the IEEE 14-bus Test System, including three biomass generators, show that the inclusion of this type of generation improves the overall reliability indices of the electrical system. [ABSTRACT FROM AUTHOR]

In this paper, the aerial biomass of citrus plantations in Spain was evaluated using destructive methods. Before cutting down the trees, their geometric variables were measured: trunk diameter at 10 cm from the ground (Dt), trunk perimeter at 10 cm from the ground (Pm), mean crown diameter (Dc), canopy height (Hc), and maximum crown height (Hmax). After geometric characterization of the tree, it was felled. This was performed with a chainsaw about 10 cm above the ground. After cutting down, trees with and without leaves were weighed, and biomass variables such as moisture, calorific value, elemental composition, and proximate analysis were measured. The predictive models obtained showed an r2 of 0.78. According to our analysis, in plantations in Spain, where the average plantation pattern is 4 × 4 m, the amount of carbon stored in a plot is 15 t of C per hectare. If leaves and wood are counted, the energy density in citrus plots can be estimated at 900 MJ/tree. However, if only wood is included in the calculation, the accumulated energy per tree is 750.3 MJ/tree, which represents 5.6 × 105 MJ/ha. [ABSTRACT FROM AUTHOR]

In-forest drying of roundwood and biomass (residues) can result in more efficient transport operations from an economical and environmental perspective. On the negative side, in-forest drying may result in dry matter losses (DML), impacting the quantity and quality of residues delivered to energy plants. This paper investigated the impact of roundwood and residues in-forest drying and DML on supply chain costs and Greenhouse Gas (GHG) emissions. For the assessment, a short-term optimization planning tool was applied to a supply chain located in Asturias, Spain, consisting of fourteen supply points and two demand points: A pulp mill (demanding roundwood) and a power plant (demanding residues). Four scenarios were included in the analysis comprising different combinations of DML for roundwood and residues resulting from in-forest drying. Our results indicate that in scenarios that include in-forest drying and DML, the negative economic effects are offset by the substantial reductions in transport costs and GHG emissions. In-forest drying of roundwood and residues without DML can result in a 6.5% reduction in supply chain costs, 14.9% fewer truckloads to destination points, and 18.1% less fuel consumption and GHG emissions. [ABSTRACT FROM AUTHOR]

Biomass is a renewable energy source that, due to its strong seasonality, needs to be stored, handled, and managed under suitable conditions for its optimal use. Storage is therefore a key process in which biomass can lose many of its qualities as a fuel, but which can also serve to improve the condition of the resource. This paper presents results from a study to assess the effect of large‐scale storage on a range of different biomass resources that was carried out at an electricity generation plant located in southern Spain. It included a series of field tests carried out with different types of biomass resources, to observe the behavior of these products during storage and the changes in their main characteristics. Based on these results, recommendations have been proposed for the optimal storage management of each of the products. The testing program confirms that the initial moisture content of the biomass, particle size, and the leafy content are critical aspects to consider to avoid self‐ignition and dry matter losses. Biomass with high moisture content should therefore be stored in small stockpiles and should be consumed immediately. This is especially important in the case of olive leaves and pine prunings when they have a high initial moisture content. Stockpiles of drier biomass, such as dried olive pomace, fruit tree pruning or dried olive pruning can reach up to 1200 t and be stored for up to 6 months, under adequately controlled conditions. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Nowadays, great emphasis is rightly given in the scientific community to hydrogen production from electrolysis. However, to achieve the politically stated target ambitions, all low-carbon sources for hydrogen production must be considered. The present work proposes a local production system of negative carbon hydrogen from lignocellulosic residual biomass using gasification and gas separation through H2-selective membranes as enabling technologies. The feedstock is pruning. In addition, the system produces heat and power for a Renewable Energy Community (REC) to increase the economic feasibility of hydrogen production via their sale. A modular basic plant is sized, based on a simplified system envisaged for RECs under the current regulatory framework in Spain (electrical renewable output of 100 kW). A network of these modular basic plants in the province of Huesca (Aragón) is simulated to create a system of hydrogen refueling stations for mobility in that area. A Levelized Cost of Hydrogen (LCOH) is proposed, comprehending the whole production chain from "field to tank", which is significant in areas where there is no infrastructure for the production and distribution of hydrogen for automotive purposes. The resulting LCOH for the whole system is 8.90 EUR/kg. Sensitivity analysis potentially values a lower LCOH, which unveils that hydrogen mobility can be largely competitive with diesel one. [ABSTRACT FROM AUTHOR]

• We present a novel integration for reducing CO 2 emissions in blast furnaces. • It combines top gas recycling, oxy-fuel regime, power to gas and biomass pyrolysis. • The integration was modelled using the extended operating line methodology. • The best performance was found for pyrolysis at 700 °C. • The CO 2 emissions were reduced by 58% (9.8 MJ/kg CO2 energy consumption) The paper introduces a novel approach for mitigating CO 2 emissions in blast furnaces by integrating top gas recycling, an oxy-fuel regime, power to gas, and biomass pyrolysis. Various case studies were conducted, involving the adjustment of pyrolysis temperatures (300 °C, 500 °C, 700 °C, and 900 °C) and varying the quantity of blast furnace gas directed to methanation for carbon recycling. Pinus radiata, abundant and cost-effective in Chile and Spain, was chosen as the biomass source. The integration was modeled using the extended operating line methodology and evaluated through 12 key performance indicators, such as flame temperature, coke consumption, CO 2 emissions, and specific primary energy consumption per unit of CO 2 avoided. Optimal performance was observed with pyrolysis at 700 °C and no blast furnace gas recycled through methanation. This configuration achieved a 58 % reduction in CO 2 emissions, with an energy consumption of 9.8 MJ/kg CO2 , and obviated the need for geological storage. Comparing this innovative proposal with other oxygen blast furnace approaches from the literature revealed a 13 percentage point improvement in CO 2 reduction over the second-best alternative. Additionally, the required electrolysis capacity, influencing capital expenditure, was 57 % lower, and energy consumption was reduced by 44 %. [ABSTRACT FROM AUTHOR]

In this study, we used Spanish National Forest Inventory (SNFI) data, Sentinel-2 imagery and ancillary data to develop models that estimate forest variables for major commercial timber plantations in northern Spain. We carried out the analysis in two stages. In the first stage, we considered plots with and without sub-meter geolocation, three pre-processing levels for the Sentinel-2 images and two machine learning algorithms. In most cases, geometrically, radiometrically, atmospherically and topographically (L2A-ATC) corrected images and the random forest algorithm provided the best results, with topographic correction producing a greater gain in model accuracy as the average slope of the plots increased. Our results did not show any clear impact of the geolocation accuracy of SNFI plots on results, suggesting that the usual geolocation accuracy of SNFI plots is adequate for developing forest models with data obtained from passive sensors. In the second stage, we used all plots together with L2A-ATC-corrected images to select five different groups of predictor variables in a cumulative process to determine the influence of each group of variables in the final RF model predictions. Yield variables produced the best fits, with R2 ranging from 0.39 to 0.46 (RMSE% ranged from 44.6% to 61.9%). Although the Sentinel-2-based estimates obtained in this research are less precise than those previously obtained with Airborne Laser Scanning (ALS) data for the same species and region, they are unbiased (Bias% was always below 1%). Therefore, accurate estimates for one hectare are expected, as they are obtained by averaging the values of 100 pixels (model resolution of 10 m pixel−1) with an expected error compensation. Moreover, the use of these models will overcome the temporal resolution problem associated with the previous ALS-based models and will enable annual updates of forest timber resource estimates to be obtained. [ABSTRACT FROM AUTHOR]

Sustainable and circular production models, such as the circular economy and circular bioeconomy, have become key mechanisms to leave behind the traditional linear model of food production. Under this approach and considering the waste biomass potential available in Spain and the Czech Republic, the main objective of this study is to analyse the most relevant aspects of the generation, use and regulation of agricultural waste biomass (AWB) in both countries. For this purpose, a scientometric analysis and systematic review of published research in the Scopus database were carried out. A complementary analysis of AWB management policies and regulations was also part of the methodology. The results show that Spain has published almost twice as much research as the Czech Republic. Furthermore, 91% of the retrieved research prioritizes the characterization and estimation of the potential of more than 15 AWB types. Among the main ones are olive residues, horticultural residues and wheat straw, which are used for producing organic amendments, bioenergy and biofuels. The results confirm that the reduction and valorization of AWB is an issue that has become more important in the last 13 years, mainly due to the policies and strategies for circular economy and circular bioeconomy. With this in mind, this study provides relevant information for governments on the aspects that need to be improved to advance in the valorization of AWB. This study also provides guidance to farmers on the reduction and/or recovery alternatives that they can implement to move towards sustainable and circular agriculture. [ABSTRACT FROM AUTHOR]

Studies in the agro-industry sector have shown the importance to evaluate the feasibility of an IBLC (a multi-product transformation plant). This paper develops a model to simulate the performance of an IBLC in Spain, using a combined approach: AHP, TOPSIS, and a hybrid simulation model. Results show that profits can be incremented by about 55.7% and environmental emissions of KgCO2e per tonne of bio-commodity produced, reduced by 24.2%. The scientific contribution covers the development of a simulation model that dynamically select suppliers based on a combination of social, environmental, and economic criteria. In addition, the model can be used to evaluate the economic and environmental feasibility of the IBLC by integrating the suppliers selection with the operations of a multi-product transformation plant. [Display omitted] • We provide a list of criteria that are relevant to choose suppliers of wheat. • We introduce the concept of ÍBLC and test its economic feasibility. • We develop an approach to integrate AHP and TOPSIS in a simulation environment. • We show, based on a case study in Spain, that the IBLC can be profitably run. • Profits increase by 55% while KgCO2e emissions reduces by 24.2%. [ABSTRACT FROM AUTHOR]

The characterization of aboveground biomass is important in forest management planning, with various objectives ranging from prevention of forest fires to restoration of burned areas, especially in fire-prone regions such as NW Spain. Although remotely sensed data have often been used to assess the recovery of standing aboveground biomass after perturbations, the data have seldom been validated in the field, and different shrub fractions have not been modelled. The main objective of the present study was to assess different vegetation parameters (cover, height, standing AGB and their fractions) in field plots established in five areas affected by wildfires between 2009 and 2016 by using Sentinel-2 spectral indices and LiDAR metrics. For this purpose, 22 sampling plots were established in 2019, and vegetation variables were measured by a combination of non-destructive measurement (cover and height) and destructive sampling (total biomass and fine samples of live and dead fractions of biomass).The structural characterization of gorse shrublands was addressed, and models of shrub cover—height, total biomass, and biomass by fraction and physiological condition—were constructed, with adjusted coefficients of determination ranging from 0.6 to 0.9. The addition of LiDAR data to optical remote sensing images improved the models. Further research should be conducted to calibrate the models in other vegetation communities. [ABSTRACT FROM AUTHOR]

The use of by-products from agricultural and forestry activity, apart from many other environmental benefits, constitutes an alternative source of income, cost reduction, and support for the principles of the circular economy. The bobal grape is a variety of red grape that is cultivated on 65 thousand hectares only in Spain. Periodic maintenance of the crop must be carried out through winter pruning from December to March. The pruning biomass is burned or crushed and incorporated into the soil, producing environmental contamination and disease transmission. The objective of this work was to use the biomass from vineyard residues in the production of binderless particleboards without using any adhesives, thereby obtaining an ecological product that would benefit the environment. In the manufacturing process, the press temperature (130 °C) and pressure (2.6 MPa) were fixed, varying the particle size (<0.25, 0.25 to 1.00, and 1.00 to 2.00), and the pressing time (15, 30, and 45 min). The results showed that by using particles smaller than 0.25 mm and applying 45 min in the hot press, panels were manufactured that are suitable for general use in a dry environment and for the manufacture of furniture according to European standards. [ABSTRACT FROM AUTHOR]

Background: Energy efficiency in buildings must be increased in order to reduce both energy intensity and greenhouse gas emissions. This study proposed the replacement of existing diesel boilers with biomass boilers, using four fuels (bulk pellets, wood chip, olive kernel and milled nutshell) to meet the energy demands of educational buildings in the region of Extremadura (Spain). High uncertainty surrounds biomass price prediction affecting the accuracy of economic feasibility analyses; thus, stochastic processes are suitable to support an improvement in the accuracy of predictions. The objective of the study is to demonstrate the feasibility of replacing diesel boilers with biomass boilers in order to revalorize agroforestry residues. Results: A stochastic simulation of the feasibility of replacing oil-fired boilers with biomass-fired boilers was carried out in this research. Up to 20 million possible scenarios of 10 years of fuel price evolution were simulated by Monte Carlo method based on empirical price trends data. Regression models were built to relate Net Present Values with discount rates, whose statistical dependency was significant. Predictions on financial indicators showed biomass fuels as the most profitable investment, rather than fuel oil. Specifically, in this study, milled nutshell was found the most profitable fuel in the simulation runs, with Net Present Value = 27,151.09 € (standard deviation = 7939.88 €) and Internal Rate of Return = 16.9% (standard deviation = 3.4%). Conclusions: Continuing to use oil-fired boilers costs more than the purchase and operation of new biomass-fired boilers, since the latter produce a higher cumulative cash flow than the initial investment within the next years. The payback period lies within the range of 4 to 6 years depending on the type of biomass fuel. Getting on the path to sustainability in education buildings can reduce up to 94.4% GHG emissions. This research contributes to promoting the use of low-emission fuels to meet the energy demand of educational buildings. Its results will have a positive effect in the region of Extremadura (Spain), as it boosts the appreciation of agro-industrial waste and economically strengthens the sector. [ABSTRACT FROM AUTHOR]

The Water Framework Directive (Directive 2000/60/EC) emphasises the need for simple tools and studies to characterise aquatic ecosystems. A wide range of methods has been developed, including different groups of biota and different taxonomic resolutions. Among these, the abundance biomass comparison (ABC) method is an important methodology widely used in marine benthic systems and well-founded from the ecological point of view. This method - with a slight modification using genera and families instead of species - was applied in a Mediterranean river (Eliche-Frío, northeast of Andalusia, Spain) using the macroinvertebrate community, together with the Margalef richness index and the Iberian BioMonitoring Working Party (IBMWP) to determine the quality of the water. The obtained results show the suitability of the ABC curves method to analyse the macroinvertebrate community and estimate the ecological status of river ecosystems. Although both, the genus and family aggregations, showed a similar trend, the values obtained with the family level indicate a worse state of contamination than those shown with the genus level. The comparison between genus and family levels with other biological indices shows that the evaluation obtained with family aggregation is more similar to those obtained with the Margalef and IBMWP indices than the evaluation based on genera; therefore, we could conclude that this level of taxonomic resolution is adequate for the use of the ABC method in assessing the ecological status of Mediterranean rivers. [ABSTRACT FROM AUTHOR]

Climate change is one of the environmental issues of global dominance and public opinion, becoming the greatest environmental challenge and of interest to researchers. In this context, planting trees on marginal agricultural land is considered a favourable measure to alleviate climate change, as they act as carbon sinks. Aerial laser scanning (ALS) data is an emerging technology for quantitative measures of C stocks. In this study, an estimation was made of the gains of C in biomass and soil in carob (Ceratonia siliqua L.) plantations established on agricultural land in southern Spain. The average above-ground biomass (AGB) corresponded to 85.5% of the total biomass (average 34.01 kg tree−1), and the root biomass (BGB) was 14.5% (6.96 kg tree−1), with a BGB/AGB ratio of 0.20. The total SOC stock in the top 20 cm of the soil (SOC-S20) was 60.70 Mg C ha−1 underneath the tree crown and 43.63 Mg C ha−1 on the non-cover (implantation) area for the C. siliqua plantations. The allometric equations correlating the biomass fractions with the dbh and Ht as independent variables showed an adequate fit for the foliage (Wf, R2adj = 0.70), whereas the fits were weaker for the rest of the fractions (R2adj < 0.60). The individual trees were detected using colour orthophotography and the tree height was estimated from 140 crowns previously delineated using the 95th percentile ALS-metric. The precision of the adjusted models was verified by plotting the correlation between the LiDAR-predicted height (HL) and the field data (R2adj = 0.80; RMSE = 0.53 m). Following the selection of the independent variable data, a linear regression model was selected for dbh estimation (R2adj = 0.64), and a potential regression model was selected for the SOC (R2adj = 0.81). Using the segmentation process, a total of 8324 trees were outlined in the study area, with an average height of 3.81 m. The biomass C stock, comprising both above- and below-ground biomass, was 4.30 Mg C ha−1 (50.67 kg tree−1), and the SOC20-S was 37.45 Mg C ha−1. The carbon accumulation rate in the biomass was 1.94 kg C tree−1 yr−1 for the plantation period. The total C stock (W-S and SOC20-S) reached 41.75 Mg ha−1 and a total of 4091.5 Mg C for the whole plantation. Gleaned from the synergy of tree cartography and these models, the distribution maps with foreseen values of average C stocks in the planted area illustrate a mosaic of C stock patterns in the carob tree plantation. [ABSTRACT FROM AUTHOR]

Energy demand is steadily growing as society becomes more industrialised. Renewable energy sources (RES) have long been used for various applications by thermal energy systems in the European Union (EU). Biomass and solar energy represent important RES in the development of energy transition in some regions such as coal-mining areas of Europe. Bioenergy is a key renewable energy storage mechanism for solar energy which, when combined, can tackle many of the barriers to the use of solar energy. Against this background, this study evaluates the potential implementation of both biomass and solar energy for energy production in coal-mining areas in Spain as a direct alternative to coal. The shown methodology relies on a comprehensive analysis of existing resources and their conversion to thermal energy from a multi-parametric point of view. The obtained results show that the solar–biomass combination can be used for thermal energy systems as a challenging option. The theoretical total hybrid-modular systems if implemented in the study area are equivalent to 1165 MWth and supply thermal energy for 170,000 single-family houses. [ABSTRACT FROM AUTHOR]

The Authors conducted a long-term follow-up study of a John Deere 1490 forwarder-mounted bundler owned by a Portuguese company and used for bundling logging residues from fast-growing eucalypt plantations located in Portugal and Spain. The study spanned 7 years, from 2011 to 2016. During this time, the machine clocked over 11,500 h and produced more than 200,000 bundles or 75,000 green tons of biomass. Bundle length was commonly 2.4 m, and bundle mass averaged 350 kg. Overall, the database contained 1752 daily records. Bundling productivity averaged 19 bundles per productive machine hour (meter hour, excluding all major delays). Mechanical availability was very high and averaged 93%. Utilization commonly ranged between 65% and 75%. Use and productivity showed a predictable seasonal trend and a slight decline over time. The latter might be due to wear, but also due to the increasingly challenging conditions faced by the company as the average worksite size sharply decreased from 2011 onwards. While almost extinct elsewhere, bundling seems to thrive in the Iberian plantations, possibly due to the industrial character of both eucalypt farming and bioenergy generation in the region. That allows the reaping of all integration benefits offered by bundling, while the cost of setting up a parallel biomass chain is minimized. Furthermore, bundling seems the ideal technique for efficient residue recovery where slash yields are low and roadside storage space is limited: these are the typical constraints of industrial eucalypt plantations, where planted area is maximized (=little landing space) and the largest possible proportion of the tree mass is turned into pulpwood (=relatively low residue yield). [ABSTRACT FROM AUTHOR]