289 research outputs found
El Foc com a causant de canvis en les propietat del sòl : incendis forestals i cremes prescrites
L'article ens aproxima als resultats d'un estudi de recerca que es fixa en l'evolució
de l'espai públic del barri del Mercadal de Girona, i més concretament
en les tres places que s'hi ubiquen: Constitució, Josep Pla i Santa Susanna.
Després de vint anys de l'inici de la transformació urbanística del barri, es fa
una anàlisi de com aquestes tres places són percebudes i viscudes per les persones
que hi habiten, especialment des d'una perspectiva de gènere.El artículo nos aproxima a los resultados de una investigación que se fija en
la evolución del espacio público del barrio del Mercadal de Gerona, y más concretamente
en las tres plazas que existen: Constitució, Josep Pla y Santa Susanna.
Después de veinte años del inicio de la transformación urbanística del barrio, se realiza un análisis sobre como se perciben estas tres plazas y como las viven
las personas que las habitan, especialmente desde una perspectiva de género.This paper presents the results of a research project focused in the evolution
of the public space of the Mercadal neighborhood of Girona, and more precisely
in the three squares that are located there: Constitució, Josep Pla and
Santa Susana. After twenty years of urban regeneration in the neighborhood,
these three spaces are analyzed from the point of view of the people that live
there and experience them, specially from a gender perspective
Evolución temporal de las propiedades del suelo tras el tratamiento de extracción de madera quemada en la Sierra de Mariola
Estudio realizado para evaluar la evolución temporal del suelo de un bosque mediterráneo en la Sierra de Mariola en Alicante, España, cinco años después de sufrir un incendio y haberse aplicado un tratamiento de extracción de madera quemada. Analizando propiedades físicas, químicas y biológicas del suelo se observa una clara degradación en la zona de saca de madera, mientras que la zona de control, donde no se extrajo madera, presenta valores estables e incluso de recuperación en algunos parámetros. El tratamiento de saca de madera ha provocado una erosión que ha afectado a la capa más fértil del suelo, reduciendo su materia orgánica y la presencia de microrganismos y nutrientes disponibles para las plantas. Con los resultados obtenidos podemos concluir que el tratamiento de extracción de madera quemada ha supuesto un proceso desfavorable para la recuperación del ecosistema tras sufrir un incendio.Study carried out to evaluate the temporal evolution of the soil of a Mediterranean forest in Sierra de Mariola at Alicante, Spain, five years after suffering a forest fire and having applied a burnt wood extraction treatment. Analyzing the physical, chemical and biological properties of the soil, a clear degradation is observed in the area of wood extraction, while the control zone, where no wood was extracted, presents stable values and even recovery in some parameters. The treatment of wood extraction has caused an erosion that has affected the most fertile layer of the soil, reducing its organic matter and the presence of microorganisms and nutrients available for the plants. With the results obtained we can conclude that the treatment of wood burnt extraction has been an unfavorable process for the recovery of the ecosystem after suffering a forest fire
Application of minidisk infiltrometer to estimate water repellency in Mediterranean pine forest soils
Assessment of soil water repellency (SWR) was conducted in the decomposed organic floor layer (duff) and in the mineral soil layer of two Mediterranean pine forests, one in Italy and the other in Spain, by the widely-used water drop penetration time (WDPT) test and alternative indices derived from infiltration experiments carried out by the minidisk infiltrometer (MDI). In particular, the repellency index (RI) was calculated as the adjusted ratio between ethanol and water soil sorptivities whereas the water repellency cessation time (WRCT) and the specifically proposed modified repellency index (RIm) were derived from the hydrophobic and wettable stages of a single water infiltration experiment. Time evolution of SWR and vegetation cover influence was also investigated at the Italian site. All indices unanimously detected severe SWR conditions in the duff of the pine forests. The mineral subsoils in the two forests showed different wettability and the clay-loam subsoil at Ciavolo forest was hydrophobic even if characterized by organic matter (OM) content similar to the wettable soil of an adjacent glade. It was therefore assumed that the composition rather than the total amount of OM influenced SWR. The hydraulic conductivity of the duff differed by a factor of 3.8-5.8 between the two forested sites thus influencing the vertical extent of SWR. Indeed, the mineral subsoil of Javea showed wettable or weak hydrophobic conditions probably because leaching of hydrophobic compounds was slowed or prevented at all. Estimations of SWR according to the different indices were in general agreement even if some discrepancies were observed. In particular, at low hydrophobicity levels the SWR indices gathered from the MDI tests were able to signal sub-critical SWR conditions that were not detected by the traditional WDPT index. The WRCT and modified repellency index RIm yielded SWR estimates in reasonable agreement with those obtained with the more cumbersome RI test and, therefore, can be proposed as alternative procedures for SWR assessment
How clear-cutting affects fire severity and soil properties in a Mediterranean ecosystem
Forest management practices in Mediterranean ecosystems are frequently employed to reduce both the
risk and severity of wildfires. However, these pre-fire treatments may influence the effects of wildfire
events on soil properties. The aim of this study is to examine the short-term effects of a wildfire that
broke out in 2015 on the soil properties of three sites: two exposed to management practices in different
years e 2005 (site M05B) and 2015 (site M15B) e and one that did not undergo any management (NMB)
and to compare their properties with those recorded in a plot (Control) unaffected by the 2015 wildfire.
We analyzed aggregate stability (AS), soil organic matter (SOM) content, total nitrogen (TN), carbon/
nitrogen ratio (C/N), inorganic carbon (IC), pH, electrical conductivity (EC), extractable calcium (Ca),
magnesium (Mg), sodium (Na), and potassium (K), microbial biomass carbon (Cmic) and basal soil
respiration (BSR). In the managed plots, a clear-cutting operation was conducted, whereby part of the
vegetation was cut and left covering the soil surface. The AS values recorded at the Control site were
significantly higher than those recorded at M05B, whereas the TN and SOM values at NMB were
significantly higher than those recorded at M05B. IC was significantly higher at M05B than at the other
plots. There were no significant differences in C/N ratio between the analyzed sites. Soil pH at M05B was
significantly higher than the value recorded at the Control plot. Extractable Ca was significantly higher at
NMB than at both M05B and the Control, while extractable Mg was significantly lower at M05B than at
NMB. Extractable K was significantly lower at the Control than at the three fire-affected plots. Cmic was
significantly higher at NMB than at the Control. BSR, BSR/C and BSR/Cmic values at the fire-affected sites were significantly lower than those recorded at the Control. No significant differences were identified in Cmic/C. Overall, a comparison of the pre-fire treatments showed that NMB was the practice that had the least negative effects on the soil properties studied, followed by M15B, and that fire severity was highest at M05B due to the accumulation of dead plant fuel
The burn severity and plant recovery relationship affect the biological and chemical soil properties of Pinus halepensis Mill. stands in the short and midterms after wildfire
In the Mediterranean Basin, changes in climate and fire regime (increased recurrence and severity) reduce
ecosystem services after wildfires by increasing soil degradation and losses in plant diversity. Our study was a
biological approach to relate soil properties to vegetation recovery and burn severity. We focused our study on
the natural recovery of the soil-plant interphase in Pinus halepensis Mill. forests located in the SE of Iberian
Peninsula, a semiarid climate. We included some chemical properties 3 years after fire (available phosphorus (P)
and soil organic carbon (Corg), among others), and biological soil indicators 3 and 5 years after fire (i.e. basal
soil respiration (BSR), microbial biomass carbon (Cmic), carbon mineralization coefficient (Cmineral), metabolic
quotient (qCO2) and microbial quotient (Cmic:Corg)). We analyzed the activity of three different enzymes: urease
(UR), phosphatase (PHP) and β-glucosidase (GLU).
The changes in most chemical properties were ephemeral, but P and Corg showed higher values in burned
areas, and the highest were found for low-moderate severity. Plant recovery was the triggering factor for the
recovery of Corg and biological soil function. Burn severity and time after fire influenced Cmic and the
Cmic:Corg, which were higher for moderate-high severity 3 years later, but were below the unburned values 5
years after fire. The microbial activities of GLU and UR were recovered in burned areas 5 years after fire. The
PHP values lowered according to higher burn severity and time after fire. The soil ecological trends obtained by a
principal component analysis revealed a relationship linking GLU, BSR and qCO2 that explained soil response to
burn severity. PHP, Cmic and Cmic:Corg explained most of the variability related to time after fire.
Our results provide insights into how burn severity, in Mediterranean fire-prone Aleppo pine stands,
modulated the natural plant recovery linked to soil biochemical and microbiological response to fire. High burn
severity limited natural vegetation recovery, and both reduced biological soil functionality. This knowledge can
be implemented in post-fire planning to apply post-fire management (for mitigation and restoration) in which
the “no intervention” tool should be contemplated. These findings provide information to be applied in adaptive
forest management to improve the resilience of vulnerable ecosystems and to reduce burn severity in future fire
events.This study was supported by a research award provided by the Instituto Estudios Albacetenses (IEA2016-Daniel Moya) and funds provided to the Forest Ecology Research Group by the University Castilla-La Mancha.The authors also thank the Spanish Institute for Agricultural and Food Research and Technology (INIA) for the funding awarded through National Research Projects GEPRIF (RTA2014-00011-C06), POSTFIRE_CARE (CGL2016-75178-C2-1-R) financed by the Spanish Research Agency (AIE), and the European Union for European Funding for Regional Development (FEDER)
El foc com a causant de canvis en les propietats del sòl. Incendis forestals i cremes prescrites
Aquest article pretén ser una aproximació als efectes que el foc té en el sòl. Primer de tot, presentem els motius pels quals els incendis forestals han esdevingut un problema mediambiental a Catalunya. Resumim l'actual política de prevenció de Grans Incendis Forestals per part dels Bombers de la Generalitat. En el cos central de l'article, donem una àmplia visió dels efectes del foc en el sòl i finalment, per a qui pugui estar interessat a trobar més informació, repassem tots els grups que es dediquen internacionalment a fer estudis en aquest mateix àmbit. Es pot comprovar l'heterogènia procedència científica dels grups involucrats en l'estudi del foc i el sòl
How clear-cutting affects fire severity and soil properties in a Mediterranean ecosystem
Forest management practices in Mediterranean ecosystems are frequently employed to reduce both the
risk and severity of wildfires. However, these pre-fire treatments may influence the effects of wildfire
events on soil properties. The aim of this study is to examine the short-term effects of a wildfire that
broke out in 2015 on the soil properties of three sites: two exposed to management practices in different
years e 2005 (site M05B) and 2015 (site M15B) e and one that did not undergo any management (NMB)
and to compare their properties with those recorded in a plot (Control) unaffected by the 2015 wildfire.
We analyzed aggregate stability (AS), soil organic matter (SOM) content, total nitrogen (TN), carbon/
nitrogen ratio (C/N), inorganic carbon (IC), pH, electrical conductivity (EC), extractable calcium (Ca),
magnesium (Mg), sodium (Na), and potassium (K), microbial biomass carbon (Cmic) and basal soil
respiration (BSR). In the managed plots, a clear-cutting operation was conducted, whereby part of the
vegetation was cut and left covering the soil surface. The AS values recorded at the Control site were
significantly higher than those recorded at M05B, whereas the TN and SOM values at NMB were
significantly higher than those recorded at M05B. IC was significantly higher at M05B than at the other
plots. There were no significant differences in C/N ratio between the analyzed sites. Soil pH at M05B was
significantly higher than the value recorded at the Control plot. Extractable Ca was significantly higher at
NMB than at both M05B and the Control, while extractable Mg was significantly lower at M05B than at
NMB. Extractable K was significantly lower at the Control than at the three fire-affected plots. Cmic was
significantly higher at NMB than at the Control. BSR, BSR/C and BSR/Cmic values at the fire-affected sites
were significantly lower than those recorded at the Control. No significant differences were identified in
Cmic/C. Overall, a comparison of the pre-fire treatments showed that NMB was the practice that had the
least negative effects on the soil properties studied, followed by M15B, and that fire severity was highest
at M05B due to the accumulation of dead plant fuelThis study was supported by the POSTFIRE Project (CGL2013-47862-C2-1 and 2-R) and the POSTFIRE_CARE Project (CGL2016-75178-C2-2-R [AEI/FEDER, UE]),financed by the Spanish Research Agency (AIE) and the European Union through European Funding for Regional Development (FEDER) and the FPU Program (FPU 014/00037) of the Ministry of Education, Cultureand Sports and Program 2014SGR825 of the Generalitat de Catalunya
Relationships between soil water repellency and microbial community composition under different plant species in a Mediterranean semiarid forest
Soil water repellency (SWR) can influence many hydrological soil properties, including water infiltration, uneven moisture distribution or water retention. In the current study we investigated how variable SWR persistence in the field is related to the soil microbial community under different plant species (P. halepensis, Q. rotundifolia, C. albidus and R. officinalis) in a Mediterranean forest. The soil microbial community was determined through phospholipid fatty acids (PLFA). The relationships between microbiological community structure and the soil properties pH, Glomalin Related Soil Protein (GRSP) and soil organic matter (SOM) content were also studied. Different statistical analyses were used: Principal Component Analysis (PCA), ANOVA, Redundancy Analysis and Pearson correlations. The highest concentrations of PLFA were found in the most water repellent samples. PCA showed that microorganism composition was more dependent of the severity of SWR than the type of plant species. In the Redundancy Analysis, SWR was the only significant factor (p<0.05) to explain PLFA distributions. The only PLFA biomarkers directly related to SWR were associated with Actinobacteria (10Me16:0, 10Me17:0 and 10Me18:0). All the results suggest that a strong dependence between SWR and microbial community composition.Ministerio de Ciencia e Innovación CGL2010-21670-C02-0
Spatial models for monitoring the spatio-temporal evolution of ashes after fire-a case study of a burnt grassland in Lithuania
Ash thickness is a key variable in the protection of
soil against erosion agents after planned and unplanned fires.
Ash thickness measurements were conducted along two transects
(flat and sloping areas) following a grided experimental
design. In order to interpolate data with accuracy and identify
the techniques with the least bias, several interpolation methods
were tested in the grided plot. Overall, the fire had a low
severity. However, the fire significantly reduced the ground
cover, especially on sloping areas, owing to the higher fire
severity and/or less biomass previous to the fire. Ash thickness
depended on fire severity and was thin where fire severity
was higher and thicker in lower fire severity sites. The ash
thickness decreased with time after the fire. Between 4 and
16 days after the fire, ash was transported by wind. The greatest
reduction took place between 16 and 34 days after the fire
as a result of rainfall, and was more efficient where fire severity
was higher. Between 34 and 45 days after the fire, no significant
differences in ash thickness were identified among
ash colours and only traces of the ash layer remained. The
omni-directional experimental variograms showed that variable
structure did not change significantly with time. The
ash spatial variability increased with time, particularly on the
slope, as a result of water erosion
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