Impact of bonfires on soil properties in an urban park in Vilnius (Lithuania)

Lighting bonfires in urban parks is a widespread practice. However, few studies have examined their impact on soil properties. The aim of this study was to analyze the impact of bonfires on the soil properties of an urban park in Vilnius, Lithuania. The properties studied were soil water repellency (SWR), aggregate stability (AS), soil organic matter (SOM) content, total nitrogen (TN), inorganic carbon (IC), pH, electrical conductivity (EC), extractable calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), aluminum (Al), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), boron (B), chromium (Cr), available phosphorus (P), silicon (Si) and sulfur (S). Soil ratios calculated were carbon/nitrogen ratio (C/N), Ca+Mg/(Na+K)1/2 (SPAR), Ca:Al and Ca:Mg. Three areas were studied: Site 1) Pinus sylvestris L. and Quercus robur L.; Site 2) Aesculus glabra Wild.; and Site 3) Pinus sylvestris L. and Acer plantanoides L. At each site, 20 samples were collected (10 within the bonfire area, 10 from a control area). The results showed significantly higher values of SOM, IC, pH, EC, Ca, Mg, Na, K, P, Al, Zn, Cu, Cr, S, C/N ratio, Ca:Al ratio and Ca:Mg ratio in bonfire soils than in control unburned soils. In bonfire soils, significantly lower values were recorded of SWR, AS, TN, SOM, Al, Mn, Fe, Cr, S and SPAR comparing to control soils. Most affected area by the bonfire was Site 1, which presented a marked increase in heavy metal content comparing to the control. The impact of soil heating was evident in AS, IC, pH, extractable Ca, Mg, Na, K, P, Al, Zn, Cu, Cr, S, and in its ratios. Protective measures are needed to limit bonfires and prohibit the burning of hazardous materials

Effect of pre- and post-wildfire management practices on plant recovery after a wildfire in Northeast Iberian Peninsula

[En] Fire and pre- or post-fire management practices shape the distribution and richness of plant species. Here, the effects of pre- and post-fire management on vegetation recovery were studied at different times, up to 18 months after a wildfire. Two months after a 2015 wildfire, 18 study plots were established (three 4-m2 plots for each treatment), vegetation regrowth was monitored and vegetal species richness (S), evenness (IT), density (D), diversity (H0) and maximum diversity (HMax) after 2, 10 and 18 months. The treatments were (1) control, unaffected by 2015 wildfire; (2) no treatment (NT), burned in 2015 wildfire and not managed; (3) managed in 2005 and burned in 2015 (M05B); (4) managed in 2015, 2 months before wildfire (M15B); (5) cut and manual removal after the 2015 wildfire (CR); (6) cut and no trunk removal randomly deposited on topsoil after the 2015 wildfire (CL). All the treatments were carried out in a Pinus halepensis Miller forest. At 10 and 18 months after the wildfire, vegetation recovery was greater in NT, CR and CL plots than in M05B and M15B the plots. By 18 months after the wildfire, Brachypodium retusum (Pers.) P. Beauv. and Rosmarinus officinalis L. were still dominant, especially in M15B, corroborating the belief that pre-fire treatment reduced ecosystem resilience and vegetal recovery compared to the NT and post-fire managed plots. Richness was significantly lower 10 months after wildfire in control plots, and IT was significantly higher in that inventory than previously in M15B. Eighteen months after the wildfire, H0 was significantly lower in M15B. Ten months post-wildfire, HMax was significantly lower in the control plots. Eighteen months after the wildfire, HMax, was significantly higher in CR, CL and M05B than in the control and M15B plots. Overall, pre-fire management was detrimental to post-fire vegetation recovery, while manual post-fire management proved beneficial

Influence of topography on sediment dynamics and soil chemical properties in a Mediterranean forest historically affected by wildfires: NE Iberian Peninsula

Wildfires are a major concern in Mediterranean areas and play an important role in the pedogenic process, as they usually increase soil credibility due to the destruction of vegetation cover and soil structure. On top of these factors, slope and aspect also determine the degree of retention and availability of water and nutrients in soils after fire, which in turn influence the recovery of vegetation and its protective effect against erosion. This work aims to describe the effects of slope and aspect on soil development in an area historically affected by wildfires. The study area is located in Ódena (NE Iberian Peninsula) in a Mediterranean forest. Four representative soil profiles were sampled from a south-facing steep slope, north-facing steep slope, south-facing gentle slope and north-facing gentle slope. In each profile 11 samples were sampled. The amount of soil organic matter (SOM), inorganic C (IC) and total N (TN) as well as cation availability, pH, and electrical conductivity (EC) were determined for all the horizons of each profile. Results showed that IC, TN, C/N ratio, pH, EC and K were mainly affected by aspect, whereas organic matter, C/N ratio, pH, EC, Ca and Mg were especially influenced by slope. Slope determined the amount and availability of SOM and nutrients, which highlights the need to prioritise the management of areas susceptible to erosion in order to ensure soil and ecosystem functionality

Minor Soil Elements in Contrasting Profiles in an Area Frequently Affected by Fire, NE Iberian Peninsula

Forest fires are a major concern in Mediterranean areas, where factors such as slope and aspect determine the degree of water and nutrient retention and their availability in soil. In this work, we analysed the effects of slope and aspect on minor soil elements. The study area was located in Ódena (NE Iberian Peninsula) in a typical Mediterranean forest. Four geomorphologically representative and contrasting soil profiles were sampled from different slopes and aspects. Eleven samples were taken from each profile at different depths. The amount of extractable aluminium (Al), iron (Fe), manganese (Mn), zinc (Zn), boron (B), and lead (Pb) and the calcium (Ca):Al ratio in all horizons of each profile were determined. The results showed that Al, Fe, and Pb and the Ca:Al ratio were mainly affected by slope, whereas Mn, Zn, and B were especially conditioned by aspect. This type of study aims to determine which areas have to be managed in order to avoid not only soil contamination by heavy metals but also a shortage of certain essential nutrients for plant regeneration and, thus, improved soil quality

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

Wildfire and forest management effects on soil properties

[eng] Forest fires are a common phenomenon in the Mediterranean ecosystem. These wildfires, post-fire weather conditions and forest management before and after the fire can cause irreversible damage to the soil. This thesis aims to study the impact of different forest management on soil physical, chemical and microbiological properties after a forest fire. Occasionally, before a forest fire, the area has been managed. The effectiveness of this management reaches up to ten years after it has been carried out, after that decrease its effectivity in the case of wildfire. The meteorological conditions after the fire are extremely important because they will allow the incorporation, or not, of the ashes produced during the fire. Among the results found in this study we can point out that even in conditions of torrential rainfall just after a forest fire, in areas where the slope is scarce or null, the ashes have the capacity to be incorporated into the soil. In cases where it is extremely necessary to carry out forest management, this should be done manually avoiding the use of heavy machinery. Another very important factor to take into account after a fire is the fire severity resulting in long-term differences in soil properties. In these areas, what is recovered is a dense vegetation cover that increases the fire risk. To avoid this situation, it is necessary to carry out a forest management between the medium- and long-term after the fire to reduce the risk of forest fire and decrease plant density and try to facilitate that the soil can recover its optimal conditions. This management between the medium and the long term after a forest fire is necessary and must be carried out in a sustainable way in order to preserve the conditions of the soil and that it is in optimal conditions for future forest fires.[cat]c Els incendis forestals son un fenomen comú en l’ecosistema Mediterrani. En relació a aquests incendis, les condicions meteorològiques post-incendi i la gestió forestal prèvia i posterior al incendi poden arribar a causar danys irreversibles en el sistema sòl. Aquesta tesi tracta de trobar l’impacte de les diferents gestions forestals en les propietats físiques, químiques i microbiològiques d’un sòl després d’un incendi forestal. De vegades, prèviament a un incendi forestal, les zones han estat gestionades. L’efectivitat d’aquesta gestió arriba fins a deu anys després d’haver estat portada a terme, passat aquest lapse de temps deixa de ser efectiva en cas d’incendi. Les condicions meteorològiques posteriors a l’incendi son extremadament importants ja que permetran la incorporació, o no, de les cendres produïdes durant l’incendi. Entre els resultats trobats en aquest estudi podem apuntar que inclús en condicions de fortes precipitacions, just després d’un incendi forestal, a les zones on el pendent es escàs o nul, les cendres tenen una capacitat de incorporar-se en el sòl. En els casos en els que es d’extrema necessitat portar-se a terme la gestió forestal, aquesta ha de realitzar-se d’una manera manual evitant utilitzar maquinària pesada. Un altre factor molt important a tenir en compte després de l’incendi és la severitat del foc resultant en diferències a llarg termini en les propietats del sòl. En aquestes zones, el que si que es recupera, és una densa cobertura vegetal que incrementa el risc d’incendi. Per a evitar aquesta situació, és necessari portar a terme una gestió forestal entre el mitjà- i el llarg- termini després de l’incendi per a disminuir el risc d’incendi forestal i disminuir la densitat vegetal i intentar facilitar que el sòl podi recuperar les seves condicions òptimes. Aquesta gestió entre el mitjà- i el llarg- termini després d’un incendi forestal és necessària i ha de portar-se a terme de manera sostenible amb l’objectiu de preservar les condicions del sòl i que aquest es trobi en òptimes condicions de cara a futurs incendis.[spa] Los incendios forestales son un fenómeno común en el ecosistema Mediterráneo. Estos incendios, las condiciones meteorológicas post-incendio y la gestión forestal previa y posterior al incendio pueden llegar a causar daños irreversibles en el sistema suelo. Esta tesis trata de hallar el impacto de diferentes gestiones forestales en las propiedades físicas, químicas y microbiológicas de un suelo después de un incendio forestal. En ocasiones, previamente a un incendio forestal, las zonas han sido gestionadas. La efectividad de esta gestión alcanza hasta diez años después de haber sido realizada, pasado ese lapso de tiempo deja de ser efectiva en caso de incendio. Las condiciones meteorológicas posteriores al incendio son extremadamente importantes ya que permitirán la incorporación, o no, de las cenizas producidas durante el incendio. Entre los resultados encontrados en este estudio podemos apuntar que incluso en condiciones de fuertes precipitaciones justo después de un incendio forestal, en las zonas donde la pendiente es escasa o nula, las cenizas tienen la capacidad de incorporarse en el suelo. En los casos en los que es de extrema necesidad llevar a cabo la gestión forestal, ésta debe realizarse de manera manual evitando usar maquinaria pesada. Otro factor muy importante a tener en cuenta después de un incendio es la severidad del fuego resultando en diferencias a largo plazo en las propiedades del suelo. En estas zonas, lo que sí se recupera, es una densa cobertura vegetal que incrementa el riesgo de incendio. Para evitar esta situación, es necesario llevar a cabo una gestión forestal entre el medio- y el largo-plazo después del incendio para disminuir el riesgo de incendio forestal y disminuir la densidad vegetal e intentar facilitar que el suelo pueda recuperar sus condiciones óptimas. Esta gestión entre el medio- y el largo-plazo después de un incendio forestal es necesaria y debe llevarse a cabo de manera sostenible con el fin de preservar las condiciones del suelo y que éste se encuentre en óptimas condiciones de cara a futuros incendios