658 research outputs found
Changes in Topsoil Properties after Centennial Scots Pine Afforestation in a European Beech Forest (NE Spain)
In this work, we studied the effects of centenary Scots pine (Pinus sylvestris L.) afforestation on topsoil properties conducted in a deforested area that was previously occupied by a natural European beech (Fagus sylvatica L.) forest. Organic layers and topsoil Ah mineral horizons (0â10 cm) were sampled in the Scots pine and European beech forests of Moncayo Natural Park (north-eastern Spain). The physical (stoniness, aggregate stability, and water repellency persistence and intensity), chemical (total organic C, total N, C/N, pH, and exchangeable Ca2+, Mg2+, Na+, K+, Al3+, and Fe3+), and physicochemical (cation exchange capacity) properties of soil were analyzed. Total organic C and N were also obtained for litter samples. The studied topsoils shared a series of common properties, such as a high stoniness and aggregate stability, very low base content, high cation exchange capacity, and extreme acidity. Soils that developed under the pinewood showed a higher soil water repellency intensity. However, K+ content was significantly higher in the beechwood soil. In both forest types, total organic C and N were similar in topsoil and litter (Hemimoder type), although C and N were pooled in different O-layers. Results indicate that pine afforestation in a deforested area was an adequate measure for soil protection since it did not show significant differences in the long term (ca. 100 years) compared to the nearby natural beech stands
Bioorthogonal Double-Fluorogenic Siliconrhodamine Probes for Intracellular Superresolution Microscopy
A series of double-fluorogenic siliconrhodamine probes were
synthesized. These tetrazine-functionalized, membrane-permeable
labels allowed site-specific bioorthogonal tagging of genetically
manipulated intracellular proteins and subsequent imaging using
super-resolution microscopy
Prediction, validation, and uncertainties of a nationâwide postâfire soil erosion risk assessment in Portugal
Wildfires are a recurrent and increasing threat in mainland Portugal, where over 4.5 million hectares of forests and scrublands have burned over the last 38 years. These fire-affected landscapes have suffered an intensification of soil erosion processes, which can negatively affect soil carbon storage, reduce fertility and forest productivity, and can become a source of pollutants. The main objective of the present study is to produce a post-fire soil erosion risk map for the forest and shrubland areas in mainland Portugal and assess its reliability. To this end, the semi-empirical MorganâMorganâFinney erosion model was used to assess the potential post-fire soil erosion according to distinct burn severity and climate scenarios, and the accuracy of the predictions was verified by an uncertainty analysis and validated against independent field datasets. The proposed approach successfully allowed mapping post-fire soil erosion in Portugal and identified the areas with higher post-fire erosion risk for past and future climate extremes. The outcomes of this study comprise a set of tools to help forest managers in their decision-making for post-fire emergency stabilization, ensuring the adequate selection of areas for mitigation to minimize the economic and environmental losses caused by fire-enhanced soil erosion.publishe
What is wrong with postâfire soil erosion modelling? A metaâanalysis on current approaches, research gaps, and future directions
In the near future, a higher occurrence of wildfires is expected due to climate change, carrying social, environmental, and economic implications. Such impacts are often associated with an increase of postâfire hydrological and erosive responses, which are difficult to predict. Soil erosion models have been proven to be a valuable tool in the decisionâmaking process, from emergency response to longâterm planning, however, they were not designed for postâfire conditions, so they need to be adapted to include fireâinduced changes.
In the recent years, there has been an increasing number of studies testing different models and adaptations for the prediction of postâfire soil erosion. However, many of these adaptations are being applied without field validation or model performance assessment. Therefore, this study aims to describe the scientific advances in the last twenty years in postâfire soil erosion modelling research and evaluate model adaptations to burned areas that aim to include: i) fireâinduced changes in soil and ground cover, ii) fireâinduced changes in infiltration, iii) burn severity, and iv) mitigation measures in their predictions. This study also discusses the strengths and weaknesses of those approaches, suggests potential improvements, and identifies directions for future research.
Results show that studies are not homogeneously distributed worldwide, neither according to the model type used, nor by regions most affected by wildfires. During calibration, 73% of the cases involved model adaptation to burned conditions, and only 21% attempted to accommodate new processes. Burn severity was addressed in 75% of the cases, whilst mitigation measures were simulated in 27%. Additionally, only a minor percentage of model predictions were validated with independent field data (17%) or assessed for uncertainties (13%). Therefore, further efforts are required on the adaptation of erosion models to burned conditions to be widely used for postâfire management decision.publishe
Changes in soil organic matter composition after Scots pine afforestation in a native European beech forest revealed by analytical pyrolysis (Py-GC/MS)
The introduction of coniferous species in former deciduous forests may exert changes in soil organic matter, particularly in its molecular composition. In this work, pyrolysis-gas chromatography-mass spectrometry was used to study changes in SOM quality related to the centennial afforestation of Scots pine in an area formerly covered by European beech forest in the NE-flank of the Moncayo Natural Park (NE-Spain). For each soil profile three organic layers (fresh litter, fragmented litter and humified litter) and mineral soil horizons (Ah, E, Bhs and C) were studied. A total of 128 compounds were identified in the pyrograms, and composition differences were detected among the organic and mineral soil layers as well as between soils under beech and pine, for the main compound classes: nitrogen compounds, aromatics, lignin methoxyphenols, polycyclic aromatic hydrocarbons, lipids and polysaccharide-derived moieties. Such chemical differences were found to be derived from the biomass composition of the predominant vegetation type that was incorporated into the soil and from its progression into the soil profile. The analysis of the distribution of alkanes indicated higher SOM stabilization in the native beech forest soil. The signal of beech biomarkers (long chain n-alkanes C31-C33) found in the pine E horizon indicates the permanence of SOM derived from the natural forest ca. 100âŻyears after the afforestation.publishe
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