Guillermo Palacios - Academia.edu (original) (raw)
Papers by Guillermo Palacios
Research Square (Research Square), Feb 1, 2024
Climate change is expected to alter many natural ecosystems around the world, by affecting plants... more Climate change is expected to alter many natural ecosystems around the world, by affecting plants growth and distribution. This is particularly emphasized for several Mediterranean plant species and communities. In this study, we investigate the suitable habitat and geographical distribution of a remarkable Mediterranean tree, Ceratonia siliqua L. (Leguminosae), in Morocco. We hypothesized a reduction in the carob tree suitable habitats under climate change scenarios. To this end, we applied the maximum entropy algorithm (Maxent) to generate current and future models using 303 occurrence points coupled with 19 bioclimatic variables. Two representative concentration pathways (RCP4.5 and RCP8.5) by 2050 and 2070 were considered as future input scenarios. The maximum entropy model provides satisfactory results, with a high value of the Area Under Curve equal to 0.987 (±0.001). Jackknife tests indicate that precipitation followed by temperature play a signi cant role in the biogeographical dynamics of the Moroccan carob tree. Thus, the obtained results con rm our hypothesis of a reduction of the suitable area under the projected climate change scenarios by 2050 and 2070. The approaches developed in this study is promising to predict the potential distribution of native Mediterranean species and can be an effective tool to support conservation and restoration programs.
R E S U M E N<br> Para evaluar el impacto del fuego en los patrones de distribución espacia... more R E S U M E N<br> Para evaluar el impacto del fuego en los patrones de distribución espacial de las especies arbóreas en el bosque Miombo de la Estación Experimental Chianga en la provincia de Huambo en Angola, se analizaron los patrones de agregación espacial y las relaciones interespecíficas de las 5 especies más frecuentes: Monotes dasyanthus, Psorospermum mechowii, Hymenocardia acida, Brachystegia tamarindoides y Albizia antunesiana, en dos hábitats bajo diferentes condiciones de manejo, uno con incendios moderados y otro sin incendios. Para analizar los patrones espaciales en las dos parcelas, utilizamos el software estadístico "Programita" basado en la función de segundo orden de Ripley K, tanto en su forma modificada L (r) como en su variante O (r) a partir de las posiciones mapeadas de puntos, en el recuento acumulado de individuos presentes en un radio creciente desde cada uno de los puntos del patrón espacial, se aplicó metodología de dos formas distintas: ...
R E S U M E N<br> Para evaluar el impacto de la falla ecológica de especies arbóreas en un ... more R E S U M E N<br> Para evaluar el impacto de la falla ecológica de especies arbóreas en un bosque de miombo, se estudió la estructura, diversidad de la regeneración forestal en dos parcelas con condiciones de manejo contrastantes (una con registro de incendios forestales de baja intensidad y otra con período de incidencia) en Chianga, Provincia de Huambo, Angola. Una parcela de muestra permanente de 40 x 30 m se ubicó al azar en cada fragmento, dividida en cuatro subparcelas de 20 x 15 m. Se midió con cinta marca Suunto π o diámetro normal de árboles comunes ≥ 1cm. La altura se mide con un hipsómetro Suunto, debido a la diferencia entre la medida obtenida y el vértice superior del árbol en la base a una distancia cercana o aislada. Se contó el número de plántulas comunes <1 cm en todas las subparcelas. Se encontraron ligeras diferencias en la estructura de los árboles. A pesar de esto, el fuego no parece haberse visto afectado negativamente por diversidades y regeneraciones...
![Research paper thumbnail of Use of Aerial Laser Scanning to Assess the Effect on C Sequestration of Oak (Quercus ilex L. subsp. ballota [Desf.]Samp-Q. suber L.) Afforestation on Agricultural Land](https://attachments.academia-assets.com/109220034/thumbnails/1.jpg)
](Geosciences, 2020
Conversion of agricultural lands to forest plantations to mitigate rising atmospheric carbon diox... more Conversion of agricultural lands to forest plantations to mitigate rising atmospheric carbon dioxide (CO2) has been proposed, but it depends on accurate estimation of the on-site carbon (C) stocks distribution. The use of aerial laser scanning (ALS) data is a rapidly evolving technology for the quantification of C stocks. We evaluated the use of allometric models together with high-density ALS data for the quantification of biomass and soil C stocks in a 14-year-old Quercus ilex and Q. suber plantation in Southwestern Spain. In 2010, a field survey was performed and tree dasometric and biomass variables were measured. Forty-five soil profiles (N = 180 soil samples) were taken systematically and the soil organic C content (SOC) was determined. Biomass and soil organic C values were regressed against individual dasometric variables and total tree height was used as a predictor variable. Aerial laser scanning data were acquired with a point density of 12 points m−2. Relationships among...
iForest - Biogeosciences and Forestry, 2018
The analysis of forest structure is a useful tool to understand stand biodiversity characterizing... more The analysis of forest structure is a useful tool to understand stand biodiversity characterizing forest ecosystems, and could help in suggesting appropriate management plans. Cedar forests in Lebanon are remnant patches that survived past human activities but are still threatened by other different anthropogenic and natural disturbances. Among these threats, the cedar web-spinning sawfly (Cephalcia tannourinensis) discovered in Tannourine Cedar Forest Nature Reserve in 1997, which is able to cause the death of trees. The aim of this study is to investigate the impact of this pest on the stand structure and regeneration of Cedrus libani in Tannourine Cedar Forest Nature Reserve located in North Lebanon. The dependence of stand structural attributes (diameter at breast height, total height and basal area) on the presence of infestation by the cedar web-spinning sawfly was identified using the Student's ttest. The Ripley's K(d) function was used to analyse the spatial pattern of cedar stands. In addition, the diameter, the vertical structure and the crown projection were characterized using the Weibull function and graphic representations. The results showed that stand structure and regeneration are significantly different between infested and non-infested stands. The cedar of Lebanon remains as the dominant species, with abundant young individuals and a good regeneration status (c = 1.0). The analysis of the spatial pattern showed a positive spatial relationship between mature Lebanese cedar trees as well as between mature and juvenile cedars, with a bigger aggregation in infested plots (6 to 10 meters) than in non-infested quadrates (2 to 7 meters), reflecting the impact of the cedar web-spinning sawfly on the stand structure and regeneration of Cedrus libani stands.
Forest Ecology and Management, 2019
Previous research has provided insights into the potential response of growth and water use effic... more Previous research has provided insights into the potential response of growth and water use efficiency to thinning in Mediterranean forests, but little is known about the potential benefits of silviculture for plantations under severe drought stress. We selected two stands of Pinus sylvestris L. and P. nigra Arnold., and used dendrochronology and carbon isotopes (δ 13 C) to understand the growth and functional responses of high-density planted pine forests to thinning in drought-prone areas. Resistance, recovery, and resilience indices were calculated for each species using BAI data. We expected heavy thinning to produce stands that were more resilient to drought, particularly for the more drought-tolerant P. nigra. Differences in the basal area increments (BAI) and intrinsic water-use efficiency (iWUE) were found between the unthinned stand and the thinned stands, for both species. After thinning, BAI decreased as iWUE increased but this relationship was only marginally significant in P. sylvestris. Thinning increased growth resistance, recovery, and resilience following the severe drought of 2012. Our findings suggest that water shortage, linked to recurrent droughts, together with high tree competition, negatively affected tree growth and increased iWUE, which explains the dieback of some of these pine plantations. We evidence the vulnerability of densely planted Mediterranean pines to the forecasted warmer and drier conditions. These results show that a heavy thinning treatment (60% of basal area removed) provides a promising silvicultural framework for the adaptation of these drought-sensitive Mediterranean mountain pine forests to the potential risks of climate change.
Forests
Miombo is one of the most widely distributed ecosystems in Angola, with a great social and enviro... more Miombo is one of the most widely distributed ecosystems in Angola, with a great social and environmental value. Thus, the rural population uses the biomass as fuel and miombo provides important ecosystem services, such as its carbon sequestration capacity. The objectives of this work were (i) to assess deforestation in miombo forest in Huambo province (Angola) during the last 20 years, (ii) to evaluate carbon storage capacity of miombo, and (iii) to calculate the charcoal productive capacity of those forests. From 2000 to 2019, 359,130 ha (12.96%) were deforested in Huambo province. Thirty-six woody species were identified as major components of miombo forest, the most frequent being Albizia anthunesiana, Brachystegia spiciformis, Julbernardia paniculata, Monote spp., Brachystegia boemii, Isoberlinea angolensis, Anisophyllea boehmii, Syzygium guineense, and Erythrophleum africanum. The total biomass estimated in miombo forest was 195.05 Mg ha−1 (55.02 Mg ha−1 radical and 140.04 Mg h...
Forests
Forests are key elements in mitigating the effects of climate change due to the fact of their car... more Forests are key elements in mitigating the effects of climate change due to the fact of their carbon sequestration capacity. Forest management can be oriented to optimise the carbon sequestration capacity of forest stands, in line with other productive objectives and the generation of ecosystem services. This research aimed to determine whether thinning treatments have a positive influence on the growth patterns of some of the main Mediterranean pine species and, therefore, on their Carbon (C) fixation capacity, both in terms of living biomass and soil organic carbon. The results obtained show that C sequestration capacity (biomass and SOC) increased at higher thinning intensities due to the induced alterations in tree growth patterns. We observed almost a 1.5-fold increase in P. nigra and P. sylvestris, respectively, and over a two-fold increase in P. pinaster under heavy thinning treatments; SOC stocks were affected by the intensity of the thinning treatments. These results can co...
Ecological Processes
Background The carob tree (Ceratonia siliqua L.) is one of the most iconic tree species of the Me... more Background The carob tree (Ceratonia siliqua L.) is one of the most iconic tree species of the Mediterranean region, with valuable economic, ecological and cultural value. Carob has been exploited around the Mediterranean region since antiquity and has been regarded as an important component of natural habitats and traditional agroecosystems. Several studies have focused on its morphological, biochemical, and genetic diversity. However, less is known about the intraspecific variation of seed traits. In this regard, and as an overall objective, we intend to evaluate the amplitude and the expression of intraspecific variations of carob seed traits at different ecological scales ranging from individual trees to different geographical landscapes. In addition, we investigated how the climate along the study area affects the extent of carob seed variability. Using image analysis techniques, we measured seven traits related to the size and the shape of 1740 seeds collected from 18 populati...
Bosque (Valdivia), 2020
The present work was carried out with the aim of analyzing and describing the seed proteome of Pi... more The present work was carried out with the aim of analyzing and describing the seed proteome of Pinus patula and Pinus greggii. The analysis was performed using the "shotgun" ("gel-free") strategy. Proteins were extracted using the TCA/Phenol/Acetone protocol, subsequently separated by liquid chromatography and analyzed by mass spectrometry (nLC LTQ Orbitrap). Protein identification was performed by consulting the specific database for Pinus spp and functional classification taking into account the three functional terms (biological processes, cellular components and molecular functions) of Gene Ontology. To extract relevant Gene Ontology terms, a singular enrichment analysis (SEA) was performed, the terms were considered relevant for a minimum threshold of significance FDR < 0.05. After analyzing protein profiles, a total of 1091 proteins were identified, 362 proteins common in both species, 100 exclusives to P. greggii and 267 exclusive proteins to P. patula. The comparative analysis of the distribution of proteins as a function of the three functional terms reveals similarity between the two species. The most abundant proteins were associated with oxidationreduction processes, in terms of cellular components; in both species integral membrane proteins predominate. Regarding molecular function, the predominant expression of proteins in both species was related to ATP synthesis. The metabolic pathway with the highest participation of proteins (17 in P. greggii and 19 in P. patula) was the glycolysis/gluconeogenesis pathway. These results demonstrate that there is little genetic variability between the two species, with proteins associated with metabolic processes prior to germination prevailing.
Forests, 2022
Proactive silviculture treatments (e.g., thinning) may increase C sequestration contributing to c... more Proactive silviculture treatments (e.g., thinning) may increase C sequestration contributing to climate change mitigation, although, there are still questions about this effect in Mediterranean pine forests. The aim of this research was to quantify the storage of biomass and soil organic carbon in Pinus forests along a climatic gradient from North to South of the Iberian Peninsula. Nine experimental Pinus spp trials were selected along a latitudinal gradient from the pre-Pyrenees to southern Spain. At each location, a homogeneous area was used as the operational scale, and three thinning intensity treatments: unthinned or control (C), intermediate thinning (LT, removal of 30–40% of the initial basal area) and heavy thinning (HT, removal of 50–60%) were conducted. Growth per unit area (e.g., expressed as basal area increment-BAI), biomass, and Soil Organic Carbon (SOC) were measured as well as three sets of environmental variables (climate, soil water availability and soil chemical a...
Forests, 2022
Biological wastewater treatment (BWWT) has been demonstrated to be a suitable procedure to degrad... more Biological wastewater treatment (BWWT) has been demonstrated to be a suitable procedure to degrade organic pollutants by utilizing natural processes. This paper presents a validated model to map land suitability for BWWT systems under the climatic conditions of Lebanon and the Litani River basin, using the Geographic Information System (GIS) and a machine learning approach for the Litani River Basin and Lebanon. The model was validated using fuzzy theory and the analytic hierarchy process (AHP) modeling theory, and a final suitability map was created in Lebanon that combined potential areas for Biological Wastewater Treatment (BWWT) based on particular criteria. Results show that spatial distribution of the suitable areas for BWWT sites differs for each of the criteria and the total extent of these potential areas is 162.94 km2 all over Lebanon and 42.62 km2 in the Litani basin areas. This area covers around 1.55% of the Lebanese areas and can help more than 30 regions while the tot...
Forests, 2021
Adaptive forest management (AFM) is an urgent need because of the uncertainty regarding how chang... more Adaptive forest management (AFM) is an urgent need because of the uncertainty regarding how changes in the climate will affect the structure, composition and function of forests during the next decades. Current research initiatives for the long-term monitoring of impacts of silviculture are scattered and not integrated into research networks, with the consequent losses of opportunities and capacity for action. To increase the scientific and practical impacts of these experiences, it is necessary to establish logical frameworks that harmonize the information and help us to define the most appropriate treatments. In this context, a number of research groups in Spain have produced research achievements and know-how during the last decades that can allow for the improvement in AFM. These groups address the issue of AFM from different fields, such as ecophysiology, ecohydrology and forest ecology, thus resulting in valuable but dispersed expertise. The main objective of this work is to i...
Son multiples los factores que afectan a la respuesta al establecimiento de las plantulas en una ... more Son multiples los factores que afectan a la respuesta al establecimiento de las plantulas en una repoblacion forestal en ambito mediterraneo, los cuales, en su conjunto, deben condicionar la calidad de la planta y la tecnica repobladora a emplear. Las condiciones ambientales tras la plantacion, el manejo realizado de la planta, asi como su morfologia y fisiologia, son considerados como los factores mas determinantes para el establecimiento de una repoblacion forestal. Entre estos factores que pueden influir en el establecimiento de las repoblaciones forestales en ambito mediterraneo, este trabajo de investigacion ha planteado como objetivo general estudiar el efecto que la fecha de plantacion, los tratamientos de preparacion del terreno utilizados y la calidad de planta, ejercen en la supervivencia y el desarrollo de las repoblaciones forestales tras su establecimiento. Para ello, se ha analizado la influencia relativa de cada uno de los factores estudiados, controlando el efecto de...
Forests, 2020
Systematic forest networks of health monitoring have been established to follow changes in tree v... more Systematic forest networks of health monitoring have been established to follow changes in tree vigor and mortality. These networks often lack long-term growth data, but they could be complemented with tree ring data, since both defoliation and radial growth are proxies of changes in tree vigor. For instance, a severe water shortage should reduce growth and increase tree defoliation in drought-prone areas. However, the effects of climatic stress and drought on growth and defoliation could also depend on tree age. To address these issues, we compared growth and defoliation data with recent climate variability and drought severity in Abies pinsapo old and young trees sampled in Southern Spain, where a systematic health network (Andalucía Permanent Plot Network) was established. Our aims were: (i) to assess the growth sensitivity of old and young A. pinsapo trees and (ii) to test if relative changes in radial growth were related with recent defoliation, for instance, after severe droug...
ISPRS International Journal of Geo-Information, 2020
The effective and efficient planning of rural land-use changes and their impact on the environmen... more The effective and efficient planning of rural land-use changes and their impact on the environment is critical for land-use managers. Many land-use growth models have been proposed for forecasting growth patterns in the last few years. In this work; a cellular automata (CA)-based land-use model (Metronamica) was tested to simulate (1999–2007) and predict (2007–2035) land-use dynamics and land-use changes in Andalucía (Spain). The model was calibrated using temporal changes in land-use covers and was evaluated by the Kappa index. GIS-based maps were generated to study major rural land-use changes (agriculture and forests). The change matrix for 1999–2007 showed an overall area change of 674971 ha. The dominant land uses in 2007 were shrubs (30.7%), woody crops on dry land (17.3%), and herbaceous crops on dry land (12.7%). The comparison between the reference and the simulated land-use maps of 2007 showed a Kappa index of 0.91. The land-cover map for the projected PRELUDE scenarios pr...
iForest - Biogeosciences and Forestry, 2018
Biogeosciences and Forestry Biogeosciences and Forestry Climate change may threaten the southernm... more Biogeosciences and Forestry Biogeosciences and Forestry Climate change may threaten the southernmost Pinus nigra subsp. salzmannii (Dunal) Franco populations: an ensemble niche-based approach Rafael M Navarro-Cerrillo (1) , Joaquín Duque-Lazo (1) , Rubén D Manzanedo (2) , Raúl Sánchez-Salguero (3) , Guillermo Palacios-Rodriguez (1) We used Species Distribution Modeling to predict the probability of Iberian pine (Pinus nigra subsp. salzmannii [Dunal] Franco) occurrences in southern Spain in response to environmental variables and to forecast the effects of climate change on their predicted geographical distribution. The ensemble modeling approach "biomod2" was used, together with present Iberian pine data, to predict the current potential distribution based on bioclimatic explanatory variables (200 m resolution) and to forecast future suitability by studying three periods (2040, 2070, and 2100), considering the Global Circulation Models BCM2, CNCM3, and ECHAM5, and the regional model EGMAM, for different scenarios (SRAB1, SRA2, SRB1). Model evaluation was performed using Kappa, True Skills Statistic (TSS), and Area Under the Curve (AUC) values. The bio-mod2 approach highlighted the average number of days with a minimum temperature equal to or below 0°C, annual precipitation, and aridity index as the most important variables to describe the P. nigra occurrence probability. Model performances were generally satisfactory and the highest AUC values and high stability of the results were given by GAM and GLM, but MaxEnt and the SRE model were scarcely accurate according to all our statistics. The ensemble Species Distribution Modeling of P. nigra in Andalusia predicted the highest probability of species occurrence in the eastern areas, Sierra de Cazorla being the area with the highest occurrence of P. nigra in Andalusia. In the future habitat, the general probability of P. nigra occurrence in Andalusia will decrease widely; the species is expected to lose habitat suitability at moderate altitudes and its occurrence probability will have decreased by nearly 70% on average by 2100, affected by the selected scenario. Populations in Sierra de Cazorla are those most suitable for P. nigra growth, even under the most pessimistic scenarios. It is likely that the natural southern populations of P. nigra will be very sensitive to changes in climate.
Forests, 2018
The assessment of the long-term impacts of drought on tree growth decline using tree-ring analyse... more The assessment of the long-term impacts of drought on tree growth decline using tree-ring analyses may be used to test if plantations are more vulnerable to warming after successive droughts, leading to a "cumulative stress" effect. We selected 76 Pinus pinaster trees (declining and non-declining trees), and basal area increments over the last 20 years (BAI 20) were calculated to build the chronologies for the stand types and vigor classes. Resistance, recovery and resilience indices were calculated. Pearson correlations, analyses and Partial Least-Squares regression were used to analyze the relationships among the response and environmental variables. We found a negative and significant relationship between mean temperature for May and June of the current year and growth in the naturally regenerated stands. This negative effect on growth under warm spring conditions was more noticeable in plantations than in naturally regenerated stands. A negative trend along time was found for the resilience index in planted stands. Evapotranspiration, maximum temperature and annual radiation showed significant and negative correlations with the growth of declining trees from planted stands, indicating they are susceptible to drought stress. Declining trees in planted stands showed a loss of growth resilience, specifically a negative trend after successive droughts.
Remote Sensing, 2018
Forest managers are interested in forest-monitoring strategies using low density Airborne Laser S... more Forest managers are interested in forest-monitoring strategies using low density Airborne Laser Scanning (ALS). However, little research has used ALS to estimate soil organic carbon (SOC) as a criterion for operational thinning. Our objective was to compare three different thinning intensities in terms of the on-site C stock after 13 years (2004–2017) and to develop models of biomass (Wt, Mg ha−1) and SOC (Mg ha−1) in Pinus halepensis forest, based on low density ALS in southern Spain. ALS was performed for the area and stand metrics were measured within 83 plots. Non-parametric kNN models were developed to estimate Wt and SOC. The overall C stock was significantly higher in plots subjected to heavy or moderate thinning (101.17 Mg ha−1 and 100.94 Mg ha−1, respectively) than in the control plots (91.83 Mg ha−1). The best Wt and SOC models provided R2 values of 0.82 (Wt, MSNPP) and 0.82 (SOC-S10, RAW). The study area will be able to stock 134,850 Mg of C under a non-intervention scena...
Journal of Maps, 2019
Land capabilities are derived by combining the land systems information with climatic, agronomic ... more Land capabilities are derived by combining the land systems information with climatic, agronomic and forestry data.
Research Square (Research Square), Feb 1, 2024
Climate change is expected to alter many natural ecosystems around the world, by affecting plants... more Climate change is expected to alter many natural ecosystems around the world, by affecting plants growth and distribution. This is particularly emphasized for several Mediterranean plant species and communities. In this study, we investigate the suitable habitat and geographical distribution of a remarkable Mediterranean tree, Ceratonia siliqua L. (Leguminosae), in Morocco. We hypothesized a reduction in the carob tree suitable habitats under climate change scenarios. To this end, we applied the maximum entropy algorithm (Maxent) to generate current and future models using 303 occurrence points coupled with 19 bioclimatic variables. Two representative concentration pathways (RCP4.5 and RCP8.5) by 2050 and 2070 were considered as future input scenarios. The maximum entropy model provides satisfactory results, with a high value of the Area Under Curve equal to 0.987 (±0.001). Jackknife tests indicate that precipitation followed by temperature play a signi cant role in the biogeographical dynamics of the Moroccan carob tree. Thus, the obtained results con rm our hypothesis of a reduction of the suitable area under the projected climate change scenarios by 2050 and 2070. The approaches developed in this study is promising to predict the potential distribution of native Mediterranean species and can be an effective tool to support conservation and restoration programs.
R E S U M E N<br> Para evaluar el impacto del fuego en los patrones de distribución espacia... more R E S U M E N<br> Para evaluar el impacto del fuego en los patrones de distribución espacial de las especies arbóreas en el bosque Miombo de la Estación Experimental Chianga en la provincia de Huambo en Angola, se analizaron los patrones de agregación espacial y las relaciones interespecíficas de las 5 especies más frecuentes: Monotes dasyanthus, Psorospermum mechowii, Hymenocardia acida, Brachystegia tamarindoides y Albizia antunesiana, en dos hábitats bajo diferentes condiciones de manejo, uno con incendios moderados y otro sin incendios. Para analizar los patrones espaciales en las dos parcelas, utilizamos el software estadístico "Programita" basado en la función de segundo orden de Ripley K, tanto en su forma modificada L (r) como en su variante O (r) a partir de las posiciones mapeadas de puntos, en el recuento acumulado de individuos presentes en un radio creciente desde cada uno de los puntos del patrón espacial, se aplicó metodología de dos formas distintas: ...
R E S U M E N<br> Para evaluar el impacto de la falla ecológica de especies arbóreas en un ... more R E S U M E N<br> Para evaluar el impacto de la falla ecológica de especies arbóreas en un bosque de miombo, se estudió la estructura, diversidad de la regeneración forestal en dos parcelas con condiciones de manejo contrastantes (una con registro de incendios forestales de baja intensidad y otra con período de incidencia) en Chianga, Provincia de Huambo, Angola. Una parcela de muestra permanente de 40 x 30 m se ubicó al azar en cada fragmento, dividida en cuatro subparcelas de 20 x 15 m. Se midió con cinta marca Suunto π o diámetro normal de árboles comunes ≥ 1cm. La altura se mide con un hipsómetro Suunto, debido a la diferencia entre la medida obtenida y el vértice superior del árbol en la base a una distancia cercana o aislada. Se contó el número de plántulas comunes <1 cm en todas las subparcelas. Se encontraron ligeras diferencias en la estructura de los árboles. A pesar de esto, el fuego no parece haberse visto afectado negativamente por diversidades y regeneraciones...
Geosciences, 2020
Conversion of agricultural lands to forest plantations to mitigate rising atmospheric carbon diox... more Conversion of agricultural lands to forest plantations to mitigate rising atmospheric carbon dioxide (CO2) has been proposed, but it depends on accurate estimation of the on-site carbon (C) stocks distribution. The use of aerial laser scanning (ALS) data is a rapidly evolving technology for the quantification of C stocks. We evaluated the use of allometric models together with high-density ALS data for the quantification of biomass and soil C stocks in a 14-year-old Quercus ilex and Q. suber plantation in Southwestern Spain. In 2010, a field survey was performed and tree dasometric and biomass variables were measured. Forty-five soil profiles (N = 180 soil samples) were taken systematically and the soil organic C content (SOC) was determined. Biomass and soil organic C values were regressed against individual dasometric variables and total tree height was used as a predictor variable. Aerial laser scanning data were acquired with a point density of 12 points m−2. Relationships among...
iForest - Biogeosciences and Forestry, 2018
The analysis of forest structure is a useful tool to understand stand biodiversity characterizing... more The analysis of forest structure is a useful tool to understand stand biodiversity characterizing forest ecosystems, and could help in suggesting appropriate management plans. Cedar forests in Lebanon are remnant patches that survived past human activities but are still threatened by other different anthropogenic and natural disturbances. Among these threats, the cedar web-spinning sawfly (Cephalcia tannourinensis) discovered in Tannourine Cedar Forest Nature Reserve in 1997, which is able to cause the death of trees. The aim of this study is to investigate the impact of this pest on the stand structure and regeneration of Cedrus libani in Tannourine Cedar Forest Nature Reserve located in North Lebanon. The dependence of stand structural attributes (diameter at breast height, total height and basal area) on the presence of infestation by the cedar web-spinning sawfly was identified using the Student's ttest. The Ripley's K(d) function was used to analyse the spatial pattern of cedar stands. In addition, the diameter, the vertical structure and the crown projection were characterized using the Weibull function and graphic representations. The results showed that stand structure and regeneration are significantly different between infested and non-infested stands. The cedar of Lebanon remains as the dominant species, with abundant young individuals and a good regeneration status (c = 1.0). The analysis of the spatial pattern showed a positive spatial relationship between mature Lebanese cedar trees as well as between mature and juvenile cedars, with a bigger aggregation in infested plots (6 to 10 meters) than in non-infested quadrates (2 to 7 meters), reflecting the impact of the cedar web-spinning sawfly on the stand structure and regeneration of Cedrus libani stands.
Forest Ecology and Management, 2019
Previous research has provided insights into the potential response of growth and water use effic... more Previous research has provided insights into the potential response of growth and water use efficiency to thinning in Mediterranean forests, but little is known about the potential benefits of silviculture for plantations under severe drought stress. We selected two stands of Pinus sylvestris L. and P. nigra Arnold., and used dendrochronology and carbon isotopes (δ 13 C) to understand the growth and functional responses of high-density planted pine forests to thinning in drought-prone areas. Resistance, recovery, and resilience indices were calculated for each species using BAI data. We expected heavy thinning to produce stands that were more resilient to drought, particularly for the more drought-tolerant P. nigra. Differences in the basal area increments (BAI) and intrinsic water-use efficiency (iWUE) were found between the unthinned stand and the thinned stands, for both species. After thinning, BAI decreased as iWUE increased but this relationship was only marginally significant in P. sylvestris. Thinning increased growth resistance, recovery, and resilience following the severe drought of 2012. Our findings suggest that water shortage, linked to recurrent droughts, together with high tree competition, negatively affected tree growth and increased iWUE, which explains the dieback of some of these pine plantations. We evidence the vulnerability of densely planted Mediterranean pines to the forecasted warmer and drier conditions. These results show that a heavy thinning treatment (60% of basal area removed) provides a promising silvicultural framework for the adaptation of these drought-sensitive Mediterranean mountain pine forests to the potential risks of climate change.
Forests
Miombo is one of the most widely distributed ecosystems in Angola, with a great social and enviro... more Miombo is one of the most widely distributed ecosystems in Angola, with a great social and environmental value. Thus, the rural population uses the biomass as fuel and miombo provides important ecosystem services, such as its carbon sequestration capacity. The objectives of this work were (i) to assess deforestation in miombo forest in Huambo province (Angola) during the last 20 years, (ii) to evaluate carbon storage capacity of miombo, and (iii) to calculate the charcoal productive capacity of those forests. From 2000 to 2019, 359,130 ha (12.96%) were deforested in Huambo province. Thirty-six woody species were identified as major components of miombo forest, the most frequent being Albizia anthunesiana, Brachystegia spiciformis, Julbernardia paniculata, Monote spp., Brachystegia boemii, Isoberlinea angolensis, Anisophyllea boehmii, Syzygium guineense, and Erythrophleum africanum. The total biomass estimated in miombo forest was 195.05 Mg ha−1 (55.02 Mg ha−1 radical and 140.04 Mg h...
Forests
Forests are key elements in mitigating the effects of climate change due to the fact of their car... more Forests are key elements in mitigating the effects of climate change due to the fact of their carbon sequestration capacity. Forest management can be oriented to optimise the carbon sequestration capacity of forest stands, in line with other productive objectives and the generation of ecosystem services. This research aimed to determine whether thinning treatments have a positive influence on the growth patterns of some of the main Mediterranean pine species and, therefore, on their Carbon (C) fixation capacity, both in terms of living biomass and soil organic carbon. The results obtained show that C sequestration capacity (biomass and SOC) increased at higher thinning intensities due to the induced alterations in tree growth patterns. We observed almost a 1.5-fold increase in P. nigra and P. sylvestris, respectively, and over a two-fold increase in P. pinaster under heavy thinning treatments; SOC stocks were affected by the intensity of the thinning treatments. These results can co...
Ecological Processes
Background The carob tree (Ceratonia siliqua L.) is one of the most iconic tree species of the Me... more Background The carob tree (Ceratonia siliqua L.) is one of the most iconic tree species of the Mediterranean region, with valuable economic, ecological and cultural value. Carob has been exploited around the Mediterranean region since antiquity and has been regarded as an important component of natural habitats and traditional agroecosystems. Several studies have focused on its morphological, biochemical, and genetic diversity. However, less is known about the intraspecific variation of seed traits. In this regard, and as an overall objective, we intend to evaluate the amplitude and the expression of intraspecific variations of carob seed traits at different ecological scales ranging from individual trees to different geographical landscapes. In addition, we investigated how the climate along the study area affects the extent of carob seed variability. Using image analysis techniques, we measured seven traits related to the size and the shape of 1740 seeds collected from 18 populati...
Bosque (Valdivia), 2020
The present work was carried out with the aim of analyzing and describing the seed proteome of Pi... more The present work was carried out with the aim of analyzing and describing the seed proteome of Pinus patula and Pinus greggii. The analysis was performed using the "shotgun" ("gel-free") strategy. Proteins were extracted using the TCA/Phenol/Acetone protocol, subsequently separated by liquid chromatography and analyzed by mass spectrometry (nLC LTQ Orbitrap). Protein identification was performed by consulting the specific database for Pinus spp and functional classification taking into account the three functional terms (biological processes, cellular components and molecular functions) of Gene Ontology. To extract relevant Gene Ontology terms, a singular enrichment analysis (SEA) was performed, the terms were considered relevant for a minimum threshold of significance FDR < 0.05. After analyzing protein profiles, a total of 1091 proteins were identified, 362 proteins common in both species, 100 exclusives to P. greggii and 267 exclusive proteins to P. patula. The comparative analysis of the distribution of proteins as a function of the three functional terms reveals similarity between the two species. The most abundant proteins were associated with oxidationreduction processes, in terms of cellular components; in both species integral membrane proteins predominate. Regarding molecular function, the predominant expression of proteins in both species was related to ATP synthesis. The metabolic pathway with the highest participation of proteins (17 in P. greggii and 19 in P. patula) was the glycolysis/gluconeogenesis pathway. These results demonstrate that there is little genetic variability between the two species, with proteins associated with metabolic processes prior to germination prevailing.
Forests, 2022
Proactive silviculture treatments (e.g., thinning) may increase C sequestration contributing to c... more Proactive silviculture treatments (e.g., thinning) may increase C sequestration contributing to climate change mitigation, although, there are still questions about this effect in Mediterranean pine forests. The aim of this research was to quantify the storage of biomass and soil organic carbon in Pinus forests along a climatic gradient from North to South of the Iberian Peninsula. Nine experimental Pinus spp trials were selected along a latitudinal gradient from the pre-Pyrenees to southern Spain. At each location, a homogeneous area was used as the operational scale, and three thinning intensity treatments: unthinned or control (C), intermediate thinning (LT, removal of 30–40% of the initial basal area) and heavy thinning (HT, removal of 50–60%) were conducted. Growth per unit area (e.g., expressed as basal area increment-BAI), biomass, and Soil Organic Carbon (SOC) were measured as well as three sets of environmental variables (climate, soil water availability and soil chemical a...
Forests, 2022
Biological wastewater treatment (BWWT) has been demonstrated to be a suitable procedure to degrad... more Biological wastewater treatment (BWWT) has been demonstrated to be a suitable procedure to degrade organic pollutants by utilizing natural processes. This paper presents a validated model to map land suitability for BWWT systems under the climatic conditions of Lebanon and the Litani River basin, using the Geographic Information System (GIS) and a machine learning approach for the Litani River Basin and Lebanon. The model was validated using fuzzy theory and the analytic hierarchy process (AHP) modeling theory, and a final suitability map was created in Lebanon that combined potential areas for Biological Wastewater Treatment (BWWT) based on particular criteria. Results show that spatial distribution of the suitable areas for BWWT sites differs for each of the criteria and the total extent of these potential areas is 162.94 km2 all over Lebanon and 42.62 km2 in the Litani basin areas. This area covers around 1.55% of the Lebanese areas and can help more than 30 regions while the tot...
Forests, 2021
Adaptive forest management (AFM) is an urgent need because of the uncertainty regarding how chang... more Adaptive forest management (AFM) is an urgent need because of the uncertainty regarding how changes in the climate will affect the structure, composition and function of forests during the next decades. Current research initiatives for the long-term monitoring of impacts of silviculture are scattered and not integrated into research networks, with the consequent losses of opportunities and capacity for action. To increase the scientific and practical impacts of these experiences, it is necessary to establish logical frameworks that harmonize the information and help us to define the most appropriate treatments. In this context, a number of research groups in Spain have produced research achievements and know-how during the last decades that can allow for the improvement in AFM. These groups address the issue of AFM from different fields, such as ecophysiology, ecohydrology and forest ecology, thus resulting in valuable but dispersed expertise. The main objective of this work is to i...
Son multiples los factores que afectan a la respuesta al establecimiento de las plantulas en una ... more Son multiples los factores que afectan a la respuesta al establecimiento de las plantulas en una repoblacion forestal en ambito mediterraneo, los cuales, en su conjunto, deben condicionar la calidad de la planta y la tecnica repobladora a emplear. Las condiciones ambientales tras la plantacion, el manejo realizado de la planta, asi como su morfologia y fisiologia, son considerados como los factores mas determinantes para el establecimiento de una repoblacion forestal. Entre estos factores que pueden influir en el establecimiento de las repoblaciones forestales en ambito mediterraneo, este trabajo de investigacion ha planteado como objetivo general estudiar el efecto que la fecha de plantacion, los tratamientos de preparacion del terreno utilizados y la calidad de planta, ejercen en la supervivencia y el desarrollo de las repoblaciones forestales tras su establecimiento. Para ello, se ha analizado la influencia relativa de cada uno de los factores estudiados, controlando el efecto de...
Forests, 2020
Systematic forest networks of health monitoring have been established to follow changes in tree v... more Systematic forest networks of health monitoring have been established to follow changes in tree vigor and mortality. These networks often lack long-term growth data, but they could be complemented with tree ring data, since both defoliation and radial growth are proxies of changes in tree vigor. For instance, a severe water shortage should reduce growth and increase tree defoliation in drought-prone areas. However, the effects of climatic stress and drought on growth and defoliation could also depend on tree age. To address these issues, we compared growth and defoliation data with recent climate variability and drought severity in Abies pinsapo old and young trees sampled in Southern Spain, where a systematic health network (Andalucía Permanent Plot Network) was established. Our aims were: (i) to assess the growth sensitivity of old and young A. pinsapo trees and (ii) to test if relative changes in radial growth were related with recent defoliation, for instance, after severe droug...
ISPRS International Journal of Geo-Information, 2020
The effective and efficient planning of rural land-use changes and their impact on the environmen... more The effective and efficient planning of rural land-use changes and their impact on the environment is critical for land-use managers. Many land-use growth models have been proposed for forecasting growth patterns in the last few years. In this work; a cellular automata (CA)-based land-use model (Metronamica) was tested to simulate (1999–2007) and predict (2007–2035) land-use dynamics and land-use changes in Andalucía (Spain). The model was calibrated using temporal changes in land-use covers and was evaluated by the Kappa index. GIS-based maps were generated to study major rural land-use changes (agriculture and forests). The change matrix for 1999–2007 showed an overall area change of 674971 ha. The dominant land uses in 2007 were shrubs (30.7%), woody crops on dry land (17.3%), and herbaceous crops on dry land (12.7%). The comparison between the reference and the simulated land-use maps of 2007 showed a Kappa index of 0.91. The land-cover map for the projected PRELUDE scenarios pr...
iForest - Biogeosciences and Forestry, 2018
Biogeosciences and Forestry Biogeosciences and Forestry Climate change may threaten the southernm... more Biogeosciences and Forestry Biogeosciences and Forestry Climate change may threaten the southernmost Pinus nigra subsp. salzmannii (Dunal) Franco populations: an ensemble niche-based approach Rafael M Navarro-Cerrillo (1) , Joaquín Duque-Lazo (1) , Rubén D Manzanedo (2) , Raúl Sánchez-Salguero (3) , Guillermo Palacios-Rodriguez (1) We used Species Distribution Modeling to predict the probability of Iberian pine (Pinus nigra subsp. salzmannii [Dunal] Franco) occurrences in southern Spain in response to environmental variables and to forecast the effects of climate change on their predicted geographical distribution. The ensemble modeling approach "biomod2" was used, together with present Iberian pine data, to predict the current potential distribution based on bioclimatic explanatory variables (200 m resolution) and to forecast future suitability by studying three periods (2040, 2070, and 2100), considering the Global Circulation Models BCM2, CNCM3, and ECHAM5, and the regional model EGMAM, for different scenarios (SRAB1, SRA2, SRB1). Model evaluation was performed using Kappa, True Skills Statistic (TSS), and Area Under the Curve (AUC) values. The bio-mod2 approach highlighted the average number of days with a minimum temperature equal to or below 0°C, annual precipitation, and aridity index as the most important variables to describe the P. nigra occurrence probability. Model performances were generally satisfactory and the highest AUC values and high stability of the results were given by GAM and GLM, but MaxEnt and the SRE model were scarcely accurate according to all our statistics. The ensemble Species Distribution Modeling of P. nigra in Andalusia predicted the highest probability of species occurrence in the eastern areas, Sierra de Cazorla being the area with the highest occurrence of P. nigra in Andalusia. In the future habitat, the general probability of P. nigra occurrence in Andalusia will decrease widely; the species is expected to lose habitat suitability at moderate altitudes and its occurrence probability will have decreased by nearly 70% on average by 2100, affected by the selected scenario. Populations in Sierra de Cazorla are those most suitable for P. nigra growth, even under the most pessimistic scenarios. It is likely that the natural southern populations of P. nigra will be very sensitive to changes in climate.
Forests, 2018
The assessment of the long-term impacts of drought on tree growth decline using tree-ring analyse... more The assessment of the long-term impacts of drought on tree growth decline using tree-ring analyses may be used to test if plantations are more vulnerable to warming after successive droughts, leading to a "cumulative stress" effect. We selected 76 Pinus pinaster trees (declining and non-declining trees), and basal area increments over the last 20 years (BAI 20) were calculated to build the chronologies for the stand types and vigor classes. Resistance, recovery and resilience indices were calculated. Pearson correlations, analyses and Partial Least-Squares regression were used to analyze the relationships among the response and environmental variables. We found a negative and significant relationship between mean temperature for May and June of the current year and growth in the naturally regenerated stands. This negative effect on growth under warm spring conditions was more noticeable in plantations than in naturally regenerated stands. A negative trend along time was found for the resilience index in planted stands. Evapotranspiration, maximum temperature and annual radiation showed significant and negative correlations with the growth of declining trees from planted stands, indicating they are susceptible to drought stress. Declining trees in planted stands showed a loss of growth resilience, specifically a negative trend after successive droughts.
Remote Sensing, 2018
Forest managers are interested in forest-monitoring strategies using low density Airborne Laser S... more Forest managers are interested in forest-monitoring strategies using low density Airborne Laser Scanning (ALS). However, little research has used ALS to estimate soil organic carbon (SOC) as a criterion for operational thinning. Our objective was to compare three different thinning intensities in terms of the on-site C stock after 13 years (2004–2017) and to develop models of biomass (Wt, Mg ha−1) and SOC (Mg ha−1) in Pinus halepensis forest, based on low density ALS in southern Spain. ALS was performed for the area and stand metrics were measured within 83 plots. Non-parametric kNN models were developed to estimate Wt and SOC. The overall C stock was significantly higher in plots subjected to heavy or moderate thinning (101.17 Mg ha−1 and 100.94 Mg ha−1, respectively) than in the control plots (91.83 Mg ha−1). The best Wt and SOC models provided R2 values of 0.82 (Wt, MSNPP) and 0.82 (SOC-S10, RAW). The study area will be able to stock 134,850 Mg of C under a non-intervention scena...
Journal of Maps, 2019
Land capabilities are derived by combining the land systems information with climatic, agronomic ... more Land capabilities are derived by combining the land systems information with climatic, agronomic and forestry data.