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

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 fuel

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

Effects of salvage logging on soil properties and vegetation recovery in a fire-affected Mediterranean forest: A two year monitoring research

Post-firemanagement can have an additional impact on the ecosystem; in somecases, evenmore severe than the fire. Salvage logging (SL) is a common practice in most fire-affected areas. The management of burnt wood can determine microclimatic conditions and seriously affect soil properties. In some cases, the way of doing it, using heavy machinery, and the vulnerability of soils to erosion and degradation can make this management potentially aggressive to soil. Research was done in “Sierra de Mariola Natural Park” (E Spain). A forest fire (N500 ha) occurred in July 2012. In February 2013, SL treatment was applied in a part of the affected forest. Plots for monitoring this effect were installed in this area and in a similar nearby area where no treatment was done, used as control (C). Soil samplings were done immediately after treatment and every 6 months during two years. Some soil properties were analysed, including organic matter (OM) content, nitrogen (N) available phosphorous (P) basal soil respiration (BSR), microbial biomass carbon (Cmic), bulk density (BD),water repellency (WR), aggregate stability (AS) and field capacity (FC). SL treatment caused an increase in BD, a decrease of AS, FC, OMand N. In the control area, in general the soil properties remained constant across the 2 years of monitoring, and the microbial parameters (BSR and Cmic), initially affected by the fire, recovered faster in C than in the SL area. Plant recovery also showed some differences between treatments. No significant differenceswere observed in the number of plant species recorded (richness) comparing C versus SL plots, but the number of individuals of each species (evenness)was significantly higher in C plots. In conclusion, we can affirmthat for the conditions of this study case, SL had a negative effect on the soil-plant system.To the “Ministerio de Economía and Competitividad” of the Spanish Government for financing the POSTFIRE project (CGL2013- 47862-C2-1-R) and Alcoi counci

Extent and persistence of soil water repellency induced by pines in different geographic regions

This work was supported by the Slovak Scientific Grant Agency VEGA Project Nos. 2/0054/14 and 2/0009/2015, the Slovak Research and Development Agency Project No. APVV-15-0160, and it results from the project implementation of the “Centre of excellence for integrated flood protection of land” (ITMS 26240120004).Peer reviewedPublisher PD

Stones resting on the top soil cause heterogeneous patterns of fire-induced water repellency

Depending on soil and fire characteristics, soil water repellency (SWR) may be induced, enhanced or destroyed by burning. The spatial pattern of SWR may be extremely heterogeneous as a consequence of the temperature peaks, the variation of fire temperature, the distribution of fuel, or the amount and type of ashes. In this research, we have studied the effect of stone cover and position on the intensity and spatial distribution of fire-induced SWR after low-, moderate- and high-severity fire. Generally, SWR increased with fire severity, but stones did induce some differences and increased the heterogeneity of the spatial distribution of fire-induced SWR. In low-stone-cover areas, SWR from soil surfaces below stones increased respect to non-covered soil surfaces. In areas under high stone cover, SWR increased from non-covered soil surfaces to soil surfaces below stones after low-severity fire. In moderate- and high-severity burnt soils under high stone cover, SWR was more severe than in non-covered soil surface, but no significant differences were observed.Ministerio de Economía y Competitividad CGL2010-21670-C02-0

Temporal characterisation of soil-plant natural recovery related to fire severity in burned Pinus halepensis Mill. forests

Despite Mediterranean ecosystems' high resilience to fire, both climate and land use change, and alterations in fire regimes increase their vulnerability to fire by affecting the long-term natural recovery of ecosystem services. The objective of this work is to study the effects of fire severity on biochemical soil indicators, such as chemical composition or enzymatic activity, related to time after fire and natural vegetation recovery (soil-plant interphase). Soil samples from three wildfires occurring 3, 15 and 21 years ago were taken in the south-eastern Iberian Peninsula (semiarid climate). Sampling included three fire severity levels in naturally regenerated (and changing to shrublands) Pinus halepensis Mill. forests. In the short-term post-fire period, phosphorus concentration, electrical conductivity and urease activity were positively linked to fire severity, and also influenced β-glucosidade activity in a negative relationship. During the 15–21-year post-fire period, the effects related to medium-high fire severity were negligible and soil quality indicators were linked to natural regeneration success. The results showed that most soil properties recovered in the long term after fire (21 years). These outcomes will help managers and stakeholders to implement management tools to stabilise soils and to restore burned ecosystems affected by medium-high fire severity. Such knowledge can be considered in adaptive forest management to reduce the negative effects of wildfires and desertification, and to improve the resilience of vulnerable ecosystems in a global change scenario.This study was supported by a grant for research initiation provided by the Excma. Diputación Albacete (DIPU4-AB2015) and by the funds provided by University Castilla-La Mancha to the Forest Ecology Research Group.The authors with to thank the Spanish Institute for Agricultural and Food Research and Technology (INIA) for the funding awarded through National Research Projects GEPRIF (RTA2014-00011-C06)