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Papers by Marta Pardos

Due to possible species complementarity, mixed stands are reported to be more productive and less... more Due to possible species complementarity, mixed stands are reported to be more productive and less vulnerable than pure stands for many forest biomes. Under the increased intensity and frequency of drought events predicted by IPCC scenarios, mixing would be a sound management strategy to increase the resistance and resilience of forests. However, only a limited number of species combinations have been studied in detail, revealing variable mixing effects. In this study, we analysed how tree resistance, recovery and resilience to specific drought events are modulated by species mixture. We test whether the relationship between drought stress and tree diversity would be consistent across a range of climatic and ecological conditions. We hypothesize that the reduced risks in mixed stands arising from drought events will be determined by species mixture. We focused on tree species of four different forest types found across Europe: (1)hemiboreal forests and broadleaved-coniferous forests,...

European Journal of Wildlife Research, 2014

Wildlife occupies a very relevant place in ecosystems by providing multiple goods and services to... more Wildlife occupies a very relevant place in ecosystems by providing multiple goods and services to society, gaining an important role in mountain systems. In this manuscript, we calculate gross margin figures associated with game hunting activity in nine European mountainous case study areas. Information about local game population and their management were collected by means of a structured questionnaire completed by the managers in charge of game species in the case study areas. Results show that in most of the cases, gross margins per hectare are negative, indicating that in these instances, the current market apparently does not justify maintaining hunting in some European mountain systems. Although more sampling efforts should be done to confirm our findings at a wider scale, our analysis reinforces the idea that other social factors, such as cultural heritage or self-consumption associated with hunting, may be crucial to wholly understand hunting in mountain systems. So we urge scientists to estimate non-market values related to hunting to better explain society priorities and therefore to efficiently guide future conservation, management, and policies in marginal and least favored mountain systems.

Journal of Soil Science and Plant Nutrition

Deux provenances (64 plants) de Chêne-liège (Quercus suber L.) originaires de l’Espagne et de la ... more Deux provenances (64 plants) de Chêne-liège (Quercus suber L.) originaires de l’Espagne et de la Tunisie ont été élevées sous deux niveaux d’intensité lumineuse (15 % (ombre modérée) et 5 % (ombre profonde) de pleine lumière) et deux régimes hydriques (plants irrigués à 100 % de la capacité au champ et plants soumis à un stress hydrique modéré) dans une pépinière en Espagne. Dix variables comprenant la survie des plants, la hauteur, le diamètre, le rapport hauteur/diamètre, les biomasses aérienne, souterraine et totale, le rapport biomasse tige/racine, le nombre et la longueur des unités de croissance ont été mesurées pour chaque provenance. Le taux de survie des plants a été de 89 % indépendamment des facteurs étudiés (provenance, lumière, régime hydrique). La hauteur des plants a été similaire pour les deux provenances, alors que leur diamètre a été significativement plus grand pour la provenance Espagnole. Le stress hydrique a affecté l’équilibre de croissance entre la hauteur et...

International audienceIn order to analyze the growth dynamics of beech seedlings growing under co... more International audienceIn order to analyze the growth dynamics of beech seedlings growing under contrasting canopy conditions, a beech stand in which two types of canopy opening (canopy release or gap creation) had been applied in 1995 was selected. Three and four years after the canopy had been opened, 113 naturally regenerated seedlings were sampled in gaps or under the canopy. The effects of canopy opening and seedling age on annual height and diameter growth were analyzed using mixed models. Under closed canopy, average annual seedling height and diameter increments were 1.2 cm and 0.18 mm, respectively. Diameter growth increased in the first year after the canopy had been opened, and exhibited considerable inter-annual variation related to climatic conditions. Conversely, height growth did not increase immediately after canopy opening, but increased regularly in the following years. Four years after the gap had been created, annual seedling height and diameter growth were 9.5 cm...

Forests

The correct aggregation of stakeholders’ preferences is a vital aspect of solving problems associ... more The correct aggregation of stakeholders’ preferences is a vital aspect of solving problems associated with natural resources. In fact, there is no one solution that permits the incorporation of those preferences into techniques that, in turn, address multiple objectives in the management of those resources. In this context, this work aims to assign, analyse, and compare the weights of importance to groups of stakeholders (representativity) starting from different approaches and methodologies: pairwise comparison matrices (using a subjective approach) and the voting power notion (when an objective approach is deployed). For the latter, a variant of the extended goal programming model is employed. The results show different weight values and, therefore, scenarios, in which the social groups defined acquire diverse importance. It is also observed that there are scenarios determined by different values of the control parameter, in which the results of the two above-mentioned approaches ...

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

iForest - Biogeosciences and Forestry, 2020

Cones of the Mediterranean stone pine (Pinus pinea L.) constitute one of the most relevant non-wo... more Cones of the Mediterranean stone pine (Pinus pinea L.) constitute one of the most relevant non-wood forest products collected in the Mediterranean forests, providing high value edible kernels. In the last years it has been observed a severe decline in the kernel-per-cone yield (kg of kernels obtained from a kg of fresh cones) through the whole area of the species. This decline has been associated with both ongoing climate change and the recent expansion over the Mediterranean Basin of the Western Conifer Seed Bug, Leptoglossus occidentalis Heideman, an exotic pest which predates seeds of conifer species. In the present work we aimed to confirm and quantify the impact of this recent decline on pine nut and kernel production, identify the main factors provoking this reduction, and give evidence over causality by a potential biotic agent. We analysed recent and historical series of pine nut and kernel production obtained in the four main regions where Pinus pinea occurs in Spain. Our results showed a significant drop in the final kernel-per-cone yield on three of the four regions analysed, reaching reductions over 50% in the most affected areas. We observed that this reduction is mainly associated with a significant and generalised drop in the kernel-per-nut yield (kg of kernels per kg of pine nuts in shell), triggered by an increment in the rate of damaged pine nuts and, to a lesser extent, a reduction in the number of pine nuts per cone. The prevalence of this reduction on kernel-per-cone yield over different years and provenances with contrasting climate reinforces the hypothesis of the implication of a biotic factor which can be aggravated on extreme drought years.

Forests

We assess how the age of Pinus sylvestris mother trees influences seed size, seed viability, germ... more We assess how the age of Pinus sylvestris mother trees influences seed size, seed viability, germination capacity and later offspring seedling survival under greenhouse conditions. Thirty trees ranging from 30 to 219 years old were selected in the north facing slopes in the Sierra de Guadarrama, where we could find the oldest Pinus sylvestris trees in central Spain. Forty cones per tree were harvested to study cone and seed characteristics (size and weight), seed viability and germination capacity related to the mother tree age. In addition, 25 germinated seeds per tree were grown in a greenhouse to assess offspring seedling survival during a death trial, where watering was stopped. Significant differences between trees in cone and seed morphological traits were observed. The age of the mother tree had a significant effect on cone size, seed size, and seed weight, but there was no effect on seed germination capacity and seed viability. Seedling survival was mainly affected by the de...

SSRN Electronic Journal, 2022

Forest Science, Jun 1, 2008

ABSTRACT Individual seedlings were mapped on eight 5 m × 5 m plots between 2003 and 2006, in two ... more ABSTRACT Individual seedlings were mapped on eight 5 m × 5 m plots between 2003 and 2006, in two differently managed Pinus sylvestris forests in Spain (group shelterwood system in Valsaín forest versus uniform system followed by soil preparation in Navafría forest). The spatial pattern of the seedlings was analyzed through the L(d) function. The spatial relationship between seedlings before and after the regeneration felling was analyzed using the intertype L rs (d) function. To study the spatial relationship between seedling distribution and either light availability or organic matter depth, the K rx (d) function was used. A practical method is proposed for obtaining the group-specific mean for several replicates: L std(d), based on the standardization of the L(d) function by the quantile bounds of the null model, which, once attained, is compared with the sum, weighted by the number of points in each replicate. Both the L std(d) group means and the point number weighted mean showed a cluster pattern for seedlings from germination to 6 years old, peaking at short scales (15-100 cm), before and after the cutting. After the cutting, the co-occurrence between germinants and older seedlings was not significant, although the L rs (d) function was positive and presented a peak (50-100 cm). Seedling emergence was positively associated with organic matter depth after the cutting. The association between seedling distribution and light was modified when the cutting was severe (>60% of tree basal area).

El objetivo de este trabajo es analizar la influencia de la cobertura vegetal y la luz en la rege... more El objetivo de este trabajo es analizar la influencia de la cobertura vegetal y la luz en la regeneracion natural del pino silvestre (Pinus sylvestris L.). Para ello se han localizado 9 situaciones comunes de cobertura de suelo en las masas de esta especie: tres diferentes espesores de aciculas del desfronde, dominancia de musgo, helechos (Pteridium aquilinum (L.) Jun subsp. aquilinum) y herbaceas, quemas de restos de corta y dos tipos de preparacion del suelo (decapado profundo y somero). Se consideraron 2 situaciones de luz: luz solar directa y sombra artificial con una malla de sombreo del 50%. La unidad experimental ha sido la maceta de 20 *20 cm2 y 20 cm de profundidad sobre la que se han reproducido las nueve situaciones de cobertura. En cada maceta se colocaron 100 y 250 semillas de pino silvestre durante 2002 y 2003 respectivamente. La germinacion fue evaluada semanalmente. Los datos se analizaron a traves de tecnicas de analisis de varianza. Los resultados mostraron que el ...

Se estudió la actividad radical desde noviembre a marzo en tres procedencias ibéricas de Quercus ... more Se estudió la actividad radical desde noviembre a marzo en tres procedencias ibéricas de Quercus suber L. (Sierra Morena occidentalLlanuras pacenses [BDJ], Sierra de San Pedro [SSP] y Parque de los Alcornocales-Serranía de Ronda [MLG]). La evolución del no y longitud de raíces blancas antes -Ni, Li -y después del repicado -PRR y Lmfue similar en MLG y BDJ. Ni descendió a partir de diciembre, recuperándose a mediados de enero; pero tras quince días en marzo con las temperaturas medias de las mínimas más bajas del ensayo, descendió de nuevo. El patrón de PRR para MLG y BDJ fue común y similar al descrito en otras especies. Las plantas de SSP entraron en reposo más tarde y alcanzaron el máximo PRR un mes antes. En las tres procedencias, la evolución de Li y Lm está en concordancia con las respectivas curvas de Ni y PRR, coincidiendo las fechas de mayor actividad radical con las de mayor longitud de raíces. Las diferencias entre procedencias en la evolución de los distintos parámetros s...

& Context Although drought is generally considered the main environmental constraint in Medit... more & Context Although drought is generally considered the main environmental constraint in Mediterranean environments, the abilitytoacclimate toand toleratefrost inearly developmental stages can be a determinant for seedling survival of many Mediterranean tree species like stone pine (Pinus pinea L.). & Aims The aim of this study was to assess the impact of the developmental stage of naturally regenerated stone pine individuals on tolerance to low temperature (LT) from summer to lateautumnandinspring,atahighlycontinental siteincentral Spain. Specifically, we tested to what extent the differences in tolerance are related to shoot heteroblasty. & Methods We assessed LT tolerance of needles from individuals at three age classes (class C1: seedlings, class C2: 4- to 8year-old saplings and class C3: >9-year-old saplings) over nine dates from summer to spring. & Results LT tolerance displayed severe seasonal trends and differed between age classes. It usually increased with sapling age. Such differences were tightly related to heteroblasty of the shoots. Our results point to a higher LT tolerance associated with larger leaf dry mass per unit area (LMA) values. No impact of late frosts on shoot growth rates was detected during this study. & Conclusions Developmental changes during early plant growth seem to play a role in frost tolerance of stone pine seedlings, a finding which furthers our understanding of regeneration dynamics in this species in areas with continental influence.

El interes ambiental, ecologico, paisajistico y productivo de las masas mixtas de Pinus pinea-Jun... more El interes ambiental, ecologico, paisajistico y productivo de las masas mixtas de Pinus pinea-Juniperus oxycedrus- Quercus ilex en el Sistema Central, y la dificultad para la regeneracion natural de las dos primeras especies, requiere del conocimiento de los mecanismos implicados en la regeneracion natural de las mismas. En el presente trabajo se avanzan los resultados de un estudio orientado a identificar las condiciones optimas para conseguir la instalacion y desarrollo de regenerado de P. pinea y J. oxycedrus en este tipo masas donde ambas especies aparecen mezcladas con mata de Q. ilex procedente de rebrote. Para ello se han utilizado los datos procedentes de tres parcelas de gran tamano (0.32 – 0.45 ha) instaladas en 2010, donde se ha procedido a muestrear con distintos niveles de intensidad el arbolado adulto y regenerado de las tres especies de estudio. Estos datos se han utilizado para desarrollar un modelo de celda (patch model) que permite predecir la probabilidad de ocurr...

Trees, 2021

Our modelling approach shows the predominance of the facilitative over the competition effects in... more Our modelling approach shows the predominance of the facilitative over the competition effects in controlling the regeneration of the studied species, thus pointing out to intra- and inter-specific coexistence mechanisms. Natural regeneration is a main issue in the management of continental Mediterranean forests. Ensuring natural forest regeneration is therefore vital for preserving ecosystem function under climate warming and increased frequency and intensity of extreme droughts. In this study, we evaluated intraspecific and inter-specific relationships between saplings and adult trees in mixed Pinus pinea-Quercus ilex-Juniperus stands in the Spanish Northern Plateau. Data were gathered from five 50 m × 60 m plots that covered different stand densities. Adult trees, saplings, and stumps were positioned, and height and diameter were measured. We developed a patch model to predict the probability of occurrence and abundance of saplings of the three species in 2.5 m × 2.5 m patches using a zero-inflated model. We considered as predictive variables abundance of adult trees, stumps, and saplings of each species, both in a patch and in its adjacent patches. Saplings of the three species showed a cluster pattern. The abundance of saplings of the three species was positively related with the current or past presence of their conspecific adult trees. The presence of adult trees of Pinus pinea plays a main role in both Quercus ilex and Juniperus dissemination. Our modelling approach shows the predominance of the facilitative effects over the competition effects in controlling the regeneration of the three species, pointing out to intra- and inter-specific coexistence mechanisms. The simulations suggested that to perpetuate the mixture, it is necessary to apply intense release cuttings in Pinus pinea trees once seedlings have been successfully established.

Forest Ecology and Management, 2021

Journal of Environmental Horticulture, 2001

Cork oak (Quercus suber L.) seedlings of two Iberian provenances (PA-SR and SM-Lp) were grown for... more Cork oak (Quercus suber L.) seedlings of two Iberian provenances (PA-SR and SM-Lp) were grown for one growing season in non-treated containers or in containers treated on their interior surfaces with white exterior latex paint containing 80 g CuCO3/liter. Copper carbonate-treated containers effectively prevented root deformation and decreased the amount of circled, kinked and matted roots formed at the container wall-medium interface. Root morphology was altered by the copper coating, so elongation of lateral roots contacting CuCO3-treated surfaces was more reduced than that of the tap root (82.7% vs 1.5%). These lateral roots showed higher branching frequency than roots contacting untreated container walls. CuCO3 treatment decreased root collar diameter, but did not influence seedling height, leaf area and tap root length. No sign of copper toxicity was observed in any seedling treated with CuCO3. Provenance had a significant effect on height, root collar diameter, tap root length ...

European Journal of Forest Research, 2020

While the effects of seed size on survival and early seedling growth have been demonstrated in Qu... more While the effects of seed size on survival and early seedling growth have been demonstrated in Quercus spp., there is a knowledge gap regarding these effects under water limiting conditions. To address this need, we studied cork oak ( Quercus suber L.) seedling development among treatments including three acorn classes (small: < 4 g, intermediate: 4–6 g), and large: ≥ 6 g) and two water regimes (well-watered versus water stressed). The following hypotheses were proposed: the reserve effect (larger seeds retain a larger proportion of reserves after germinating), the metabolic effect (seedlings from larger seeds have slower relative growth rates), the seedling-size effect (larger seeds produce larger seedlings), and that plant tolerance to water stress increases with increasing seed size. Acorn size had no effect on duration and rate of acorn germination nor on seedling survival, but it significantly affected almost all growth parameters, excepting the number of growth unit and leaves and leaf area. Seedlings coming from large acorns always showed the highest values for the affected growth parameters, followed by those coming from acorns of intermediate size; seedlings coming from small acorns always exhibited the lowest values. Water stress significantly affected survival rate (88.2% for well-watered seedlings versus 64.7% for water stressed seedlings) and biomass of fine roots and stems, but independently of acorn size. Our results are in line with both hypothesizes of the reserve effect and seedling-size effect, but not for the metabolic effect nor the plant tolerance to water stress increases with increasing seed size hypotheses. In general, our results show that large acorns had no advantage in survival or seedling growth under water stress comparatively to intermediate or small acorns, at least under the conditions of our experiment.

Due to possible species complementarity, mixed stands are reported to be more productive and less... more Due to possible species complementarity, mixed stands are reported to be more productive and less vulnerable than pure stands for many forest biomes. Under the increased intensity and frequency of drought events predicted by IPCC scenarios, mixing would be a sound management strategy to increase the resistance and resilience of forests. However, only a limited number of species combinations have been studied in detail, revealing variable mixing effects. In this study, we analysed how tree resistance, recovery and resilience to specific drought events are modulated by species mixture. We test whether the relationship between drought stress and tree diversity would be consistent across a range of climatic and ecological conditions. We hypothesize that the reduced risks in mixed stands arising from drought events will be determined by species mixture. We focused on tree species of four different forest types found across Europe: (1)hemiboreal forests and broadleaved-coniferous forests,...

European Journal of Wildlife Research, 2014

Wildlife occupies a very relevant place in ecosystems by providing multiple goods and services to... more Wildlife occupies a very relevant place in ecosystems by providing multiple goods and services to society, gaining an important role in mountain systems. In this manuscript, we calculate gross margin figures associated with game hunting activity in nine European mountainous case study areas. Information about local game population and their management were collected by means of a structured questionnaire completed by the managers in charge of game species in the case study areas. Results show that in most of the cases, gross margins per hectare are negative, indicating that in these instances, the current market apparently does not justify maintaining hunting in some European mountain systems. Although more sampling efforts should be done to confirm our findings at a wider scale, our analysis reinforces the idea that other social factors, such as cultural heritage or self-consumption associated with hunting, may be crucial to wholly understand hunting in mountain systems. So we urge scientists to estimate non-market values related to hunting to better explain society priorities and therefore to efficiently guide future conservation, management, and policies in marginal and least favored mountain systems.

Journal of Soil Science and Plant Nutrition

Deux provenances (64 plants) de Chêne-liège (Quercus suber L.) originaires de l’Espagne et de la ... more Deux provenances (64 plants) de Chêne-liège (Quercus suber L.) originaires de l’Espagne et de la Tunisie ont été élevées sous deux niveaux d’intensité lumineuse (15 % (ombre modérée) et 5 % (ombre profonde) de pleine lumière) et deux régimes hydriques (plants irrigués à 100 % de la capacité au champ et plants soumis à un stress hydrique modéré) dans une pépinière en Espagne. Dix variables comprenant la survie des plants, la hauteur, le diamètre, le rapport hauteur/diamètre, les biomasses aérienne, souterraine et totale, le rapport biomasse tige/racine, le nombre et la longueur des unités de croissance ont été mesurées pour chaque provenance. Le taux de survie des plants a été de 89 % indépendamment des facteurs étudiés (provenance, lumière, régime hydrique). La hauteur des plants a été similaire pour les deux provenances, alors que leur diamètre a été significativement plus grand pour la provenance Espagnole. Le stress hydrique a affecté l’équilibre de croissance entre la hauteur et...

International audienceIn order to analyze the growth dynamics of beech seedlings growing under co... more International audienceIn order to analyze the growth dynamics of beech seedlings growing under contrasting canopy conditions, a beech stand in which two types of canopy opening (canopy release or gap creation) had been applied in 1995 was selected. Three and four years after the canopy had been opened, 113 naturally regenerated seedlings were sampled in gaps or under the canopy. The effects of canopy opening and seedling age on annual height and diameter growth were analyzed using mixed models. Under closed canopy, average annual seedling height and diameter increments were 1.2 cm and 0.18 mm, respectively. Diameter growth increased in the first year after the canopy had been opened, and exhibited considerable inter-annual variation related to climatic conditions. Conversely, height growth did not increase immediately after canopy opening, but increased regularly in the following years. Four years after the gap had been created, annual seedling height and diameter growth were 9.5 cm...

Forests

The correct aggregation of stakeholders’ preferences is a vital aspect of solving problems associ... more The correct aggregation of stakeholders’ preferences is a vital aspect of solving problems associated with natural resources. In fact, there is no one solution that permits the incorporation of those preferences into techniques that, in turn, address multiple objectives in the management of those resources. In this context, this work aims to assign, analyse, and compare the weights of importance to groups of stakeholders (representativity) starting from different approaches and methodologies: pairwise comparison matrices (using a subjective approach) and the voting power notion (when an objective approach is deployed). For the latter, a variant of the extended goal programming model is employed. The results show different weight values and, therefore, scenarios, in which the social groups defined acquire diverse importance. It is also observed that there are scenarios determined by different values of the control parameter, in which the results of the two above-mentioned approaches ...

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

iForest - Biogeosciences and Forestry, 2020

Cones of the Mediterranean stone pine (Pinus pinea L.) constitute one of the most relevant non-wo... more Cones of the Mediterranean stone pine (Pinus pinea L.) constitute one of the most relevant non-wood forest products collected in the Mediterranean forests, providing high value edible kernels. In the last years it has been observed a severe decline in the kernel-per-cone yield (kg of kernels obtained from a kg of fresh cones) through the whole area of the species. This decline has been associated with both ongoing climate change and the recent expansion over the Mediterranean Basin of the Western Conifer Seed Bug, Leptoglossus occidentalis Heideman, an exotic pest which predates seeds of conifer species. In the present work we aimed to confirm and quantify the impact of this recent decline on pine nut and kernel production, identify the main factors provoking this reduction, and give evidence over causality by a potential biotic agent. We analysed recent and historical series of pine nut and kernel production obtained in the four main regions where Pinus pinea occurs in Spain. Our results showed a significant drop in the final kernel-per-cone yield on three of the four regions analysed, reaching reductions over 50% in the most affected areas. We observed that this reduction is mainly associated with a significant and generalised drop in the kernel-per-nut yield (kg of kernels per kg of pine nuts in shell), triggered by an increment in the rate of damaged pine nuts and, to a lesser extent, a reduction in the number of pine nuts per cone. The prevalence of this reduction on kernel-per-cone yield over different years and provenances with contrasting climate reinforces the hypothesis of the implication of a biotic factor which can be aggravated on extreme drought years.

Forests

We assess how the age of Pinus sylvestris mother trees influences seed size, seed viability, germ... more We assess how the age of Pinus sylvestris mother trees influences seed size, seed viability, germination capacity and later offspring seedling survival under greenhouse conditions. Thirty trees ranging from 30 to 219 years old were selected in the north facing slopes in the Sierra de Guadarrama, where we could find the oldest Pinus sylvestris trees in central Spain. Forty cones per tree were harvested to study cone and seed characteristics (size and weight), seed viability and germination capacity related to the mother tree age. In addition, 25 germinated seeds per tree were grown in a greenhouse to assess offspring seedling survival during a death trial, where watering was stopped. Significant differences between trees in cone and seed morphological traits were observed. The age of the mother tree had a significant effect on cone size, seed size, and seed weight, but there was no effect on seed germination capacity and seed viability. Seedling survival was mainly affected by the de...

SSRN Electronic Journal, 2022

Forest Science, Jun 1, 2008

ABSTRACT Individual seedlings were mapped on eight 5 m × 5 m plots between 2003 and 2006, in two ... more ABSTRACT Individual seedlings were mapped on eight 5 m × 5 m plots between 2003 and 2006, in two differently managed Pinus sylvestris forests in Spain (group shelterwood system in Valsaín forest versus uniform system followed by soil preparation in Navafría forest). The spatial pattern of the seedlings was analyzed through the L(d) function. The spatial relationship between seedlings before and after the regeneration felling was analyzed using the intertype L rs (d) function. To study the spatial relationship between seedling distribution and either light availability or organic matter depth, the K rx (d) function was used. A practical method is proposed for obtaining the group-specific mean for several replicates: L std(d), based on the standardization of the L(d) function by the quantile bounds of the null model, which, once attained, is compared with the sum, weighted by the number of points in each replicate. Both the L std(d) group means and the point number weighted mean showed a cluster pattern for seedlings from germination to 6 years old, peaking at short scales (15-100 cm), before and after the cutting. After the cutting, the co-occurrence between germinants and older seedlings was not significant, although the L rs (d) function was positive and presented a peak (50-100 cm). Seedling emergence was positively associated with organic matter depth after the cutting. The association between seedling distribution and light was modified when the cutting was severe (&gt;60% of tree basal area).

El objetivo de este trabajo es analizar la influencia de la cobertura vegetal y la luz en la rege... more El objetivo de este trabajo es analizar la influencia de la cobertura vegetal y la luz en la regeneracion natural del pino silvestre (Pinus sylvestris L.). Para ello se han localizado 9 situaciones comunes de cobertura de suelo en las masas de esta especie: tres diferentes espesores de aciculas del desfronde, dominancia de musgo, helechos (Pteridium aquilinum (L.) Jun subsp. aquilinum) y herbaceas, quemas de restos de corta y dos tipos de preparacion del suelo (decapado profundo y somero). Se consideraron 2 situaciones de luz: luz solar directa y sombra artificial con una malla de sombreo del 50%. La unidad experimental ha sido la maceta de 20 *20 cm2 y 20 cm de profundidad sobre la que se han reproducido las nueve situaciones de cobertura. En cada maceta se colocaron 100 y 250 semillas de pino silvestre durante 2002 y 2003 respectivamente. La germinacion fue evaluada semanalmente. Los datos se analizaron a traves de tecnicas de analisis de varianza. Los resultados mostraron que el ...

Se estudió la actividad radical desde noviembre a marzo en tres procedencias ibéricas de Quercus ... more Se estudió la actividad radical desde noviembre a marzo en tres procedencias ibéricas de Quercus suber L. (Sierra Morena occidentalLlanuras pacenses [BDJ], Sierra de San Pedro [SSP] y Parque de los Alcornocales-Serranía de Ronda [MLG]). La evolución del no y longitud de raíces blancas antes -Ni, Li -y después del repicado -PRR y Lmfue similar en MLG y BDJ. Ni descendió a partir de diciembre, recuperándose a mediados de enero; pero tras quince días en marzo con las temperaturas medias de las mínimas más bajas del ensayo, descendió de nuevo. El patrón de PRR para MLG y BDJ fue común y similar al descrito en otras especies. Las plantas de SSP entraron en reposo más tarde y alcanzaron el máximo PRR un mes antes. En las tres procedencias, la evolución de Li y Lm está en concordancia con las respectivas curvas de Ni y PRR, coincidiendo las fechas de mayor actividad radical con las de mayor longitud de raíces. Las diferencias entre procedencias en la evolución de los distintos parámetros s...

& Context Although drought is generally considered the main environmental constraint in Medit... more & Context Although drought is generally considered the main environmental constraint in Mediterranean environments, the abilitytoacclimate toand toleratefrost inearly developmental stages can be a determinant for seedling survival of many Mediterranean tree species like stone pine (Pinus pinea L.). & Aims The aim of this study was to assess the impact of the developmental stage of naturally regenerated stone pine individuals on tolerance to low temperature (LT) from summer to lateautumnandinspring,atahighlycontinental siteincentral Spain. Specifically, we tested to what extent the differences in tolerance are related to shoot heteroblasty. & Methods We assessed LT tolerance of needles from individuals at three age classes (class C1: seedlings, class C2: 4- to 8year-old saplings and class C3: >9-year-old saplings) over nine dates from summer to spring. & Results LT tolerance displayed severe seasonal trends and differed between age classes. It usually increased with sapling age. Such differences were tightly related to heteroblasty of the shoots. Our results point to a higher LT tolerance associated with larger leaf dry mass per unit area (LMA) values. No impact of late frosts on shoot growth rates was detected during this study. & Conclusions Developmental changes during early plant growth seem to play a role in frost tolerance of stone pine seedlings, a finding which furthers our understanding of regeneration dynamics in this species in areas with continental influence.

El interes ambiental, ecologico, paisajistico y productivo de las masas mixtas de Pinus pinea-Jun... more El interes ambiental, ecologico, paisajistico y productivo de las masas mixtas de Pinus pinea-Juniperus oxycedrus- Quercus ilex en el Sistema Central, y la dificultad para la regeneracion natural de las dos primeras especies, requiere del conocimiento de los mecanismos implicados en la regeneracion natural de las mismas. En el presente trabajo se avanzan los resultados de un estudio orientado a identificar las condiciones optimas para conseguir la instalacion y desarrollo de regenerado de P. pinea y J. oxycedrus en este tipo masas donde ambas especies aparecen mezcladas con mata de Q. ilex procedente de rebrote. Para ello se han utilizado los datos procedentes de tres parcelas de gran tamano (0.32 – 0.45 ha) instaladas en 2010, donde se ha procedido a muestrear con distintos niveles de intensidad el arbolado adulto y regenerado de las tres especies de estudio. Estos datos se han utilizado para desarrollar un modelo de celda (patch model) que permite predecir la probabilidad de ocurr...

Trees, 2021

Our modelling approach shows the predominance of the facilitative over the competition effects in... more Our modelling approach shows the predominance of the facilitative over the competition effects in controlling the regeneration of the studied species, thus pointing out to intra- and inter-specific coexistence mechanisms. Natural regeneration is a main issue in the management of continental Mediterranean forests. Ensuring natural forest regeneration is therefore vital for preserving ecosystem function under climate warming and increased frequency and intensity of extreme droughts. In this study, we evaluated intraspecific and inter-specific relationships between saplings and adult trees in mixed Pinus pinea-Quercus ilex-Juniperus stands in the Spanish Northern Plateau. Data were gathered from five 50 m × 60 m plots that covered different stand densities. Adult trees, saplings, and stumps were positioned, and height and diameter were measured. We developed a patch model to predict the probability of occurrence and abundance of saplings of the three species in 2.5 m × 2.5 m patches using a zero-inflated model. We considered as predictive variables abundance of adult trees, stumps, and saplings of each species, both in a patch and in its adjacent patches. Saplings of the three species showed a cluster pattern. The abundance of saplings of the three species was positively related with the current or past presence of their conspecific adult trees. The presence of adult trees of Pinus pinea plays a main role in both Quercus ilex and Juniperus dissemination. Our modelling approach shows the predominance of the facilitative effects over the competition effects in controlling the regeneration of the three species, pointing out to intra- and inter-specific coexistence mechanisms. The simulations suggested that to perpetuate the mixture, it is necessary to apply intense release cuttings in Pinus pinea trees once seedlings have been successfully established.

Forest Ecology and Management, 2021

Journal of Environmental Horticulture, 2001

Cork oak (Quercus suber L.) seedlings of two Iberian provenances (PA-SR and SM-Lp) were grown for... more Cork oak (Quercus suber L.) seedlings of two Iberian provenances (PA-SR and SM-Lp) were grown for one growing season in non-treated containers or in containers treated on their interior surfaces with white exterior latex paint containing 80 g CuCO3/liter. Copper carbonate-treated containers effectively prevented root deformation and decreased the amount of circled, kinked and matted roots formed at the container wall-medium interface. Root morphology was altered by the copper coating, so elongation of lateral roots contacting CuCO3-treated surfaces was more reduced than that of the tap root (82.7% vs 1.5%). These lateral roots showed higher branching frequency than roots contacting untreated container walls. CuCO3 treatment decreased root collar diameter, but did not influence seedling height, leaf area and tap root length. No sign of copper toxicity was observed in any seedling treated with CuCO3. Provenance had a significant effect on height, root collar diameter, tap root length ...

European Journal of Forest Research, 2020

While the effects of seed size on survival and early seedling growth have been demonstrated in Qu... more While the effects of seed size on survival and early seedling growth have been demonstrated in Quercus spp., there is a knowledge gap regarding these effects under water limiting conditions. To address this need, we studied cork oak ( Quercus suber L.) seedling development among treatments including three acorn classes (small: < 4 g, intermediate: 4–6 g), and large: ≥ 6 g) and two water regimes (well-watered versus water stressed). The following hypotheses were proposed: the reserve effect (larger seeds retain a larger proportion of reserves after germinating), the metabolic effect (seedlings from larger seeds have slower relative growth rates), the seedling-size effect (larger seeds produce larger seedlings), and that plant tolerance to water stress increases with increasing seed size. Acorn size had no effect on duration and rate of acorn germination nor on seedling survival, but it significantly affected almost all growth parameters, excepting the number of growth unit and leaves and leaf area. Seedlings coming from large acorns always showed the highest values for the affected growth parameters, followed by those coming from acorns of intermediate size; seedlings coming from small acorns always exhibited the lowest values. Water stress significantly affected survival rate (88.2% for well-watered seedlings versus 64.7% for water stressed seedlings) and biomass of fine roots and stems, but independently of acorn size. Our results are in line with both hypothesizes of the reserve effect and seedling-size effect, but not for the metabolic effect nor the plant tolerance to water stress increases with increasing seed size hypotheses. In general, our results show that large acorns had no advantage in survival or seedling growth under water stress comparatively to intermediate or small acorns, at least under the conditions of our experiment.