Genesis and stability of textural pedofeatures along a soil transect in the siliceous Iberian Chain (NE Spain)

Textural features are widespread in many soils, provide pedogenetic evidence, and are fundamental in soil classification systems. The presence of these features and their conservation over time require certain processes and soil forming factors. This study investigates the genesis of textural pedofeatures, especially clay coatings, and the stressful conditions that can eventually lead to their disappearance. To achieve this goal, four profiles with clay-enriched horizons have been studied (macro- and micromorphology, physical, chemical and mineralogical properties and classification) along a transect in the siliceous Iberian Chain (NE-Spain). The profiles, which have unmistakable illuvial accumulations in various horizons (Bhs, Bt, Btk), are classified (ST/WRB) as: a Spodosol/Podzol in the headslope, two Alfisol/Luvisols in the backslope and an Alfisol/Calcisol in the footslope. For the latter soil, the apparently strong difference in their classification to the first hierarchical level is due to the weight that the WRB places on the presence of an argic recarbonated horizon on a calcic horizon. Clay illuviation was identified in all the soils, with coatings and infillings of microlaminated clay. These clayey pedofeatures are mostly mechanically fragmented or deformed, which is micromorphologically evidenced by an undulating, wavy extinction that does not run completely parallel to the surfaces they cover. Different destructive processes are identified along the soil transect; so, cryoturbation is the dominant process in the Podzol located at the highest elevation (Moncayo Massif). Instead, the clay coatings in the Btk horizon of the footslope (Calcisol) are covered and deformed by the growth of secondary calcite. The textural pedofeatures in this soil, which is very clayey, can also undergo argilloturbation processes, like in the backslope soils (Luvisols). In conclusion, several ongoing stress processes, that sometimes require different environmental conditions (polygenetic), affect most textural pedofeatures and lead to their progressive alteration and disappearance.Different projects of the Research Results Transfer Office of the University of Zaragoza (Ref. 2017/0535, ref. 2018/0416; ref. UZ2020-TEC-01) provided financial support for this research

Dinámicas ambientales y paisajísticas ligadas al abandono rural del Supramediterráneo de Gúdar-Maestrazgo (Sistema Ibérico)

214 p

Living on the edge: contrasted wood-formation dynamics in Fagus sylvatica and Pinus sylvestris under Mediterranean conditions

Wood formation in European beech (Fagus sylvatica L.) and Scots pine (Pinus sylvestris L.) was intra-annually monitored to examine plastic responses of the xylem phenology according to altitude in one of the southernmost areas of their distribution range, i.e., in the Moncayo Natural Park, Spain. The monitoring was done from 2011 to 2013 at 1180 and 1580 m a.s.l., corresponding to the lower and upper limits of European beech forest in this region. Microcores containing phloem, cambium and xylem were collected biweekly from twenty-four trees from the beginning of March to the end of November to assess the different phases of wood formation. The samples were prepared for light microscopy to observe the following phenological phases: onset and end of cell production, onset and end of secondary wall formation in xylem cells and onset of cell maturation. The temporal dynamics of wood formation widely differed among years, altitudes and tree species. For Fagus sylvatica, the onset of cambial activity varied between the first week of May and the third week of June. Cambial activity then slowed down and stopped in summer, resulting in a length of growing season of 48–75 days. In contrast, the growing season for P. sylvestris started earlier and cambium remained active in autumn, leading to a period of activity varying from 139-170 days. The intra-annual wood-formation pattern is site and species-specific. Comparison with other studies shows a clear latitudinal trend in the duration of wood formation, positive for Fagus sylvatica and negative for P. sylvestris.Publishe

Dendro-anthracological tools applied to Scots type pine forests exploitation as fuel during the Mesolithic-Neolithic transition in the southern central pre-Pyrenees (Spain)

This work focuses on the reconstruction of fuelwood procurement during the Mesolithic-Neolithic transition in the southern central Pre-Pyrenees (Spain). The study combines wood charcoal identification with the application of dendro-anthracological approaches in the archaeological sequence of Esplugón (9.4–6.8 kyr cal BP) (Sabiñanigo, Huesca). Scots type pine (Pinus sylvestris tp.) reaches in this record around 90% of exploited firewood in line with its abundance in the inner Iberia mountainous areas during the onset of the Holocene. The classification of pine wood fragments in anthraco-groups is based on the combination of different dendro-anthracological tools: i) pith location tool and wood diameter estimation based on the trigonomethric method tool (ADmodel), ii) the study of growth rate based on the annual tree-ring width measurements, and iii) a modern dendrological dataset. There are hardly any differences observed in firewood procurement between the last hunter-gatherers and the first farmers in the long sequences from rock-shelters with recurrent human occupations. First results from this site point to the exploitation of whole trees but a high use of small pine branches probably from the gathering of branch shedding

SPREAD: a high-resolution daily gridded precipitation dataset for Spain – an extreme events frequency and intensity overview

A high-resolution daily gridded precipitation dataset was built from raw data of 12 858 observatories covering a period from 1950 to 2012 in peninsular Spain and 1971 to 2012 in Balearic and Canary islands. The original data were quality-controlled and gaps were filled on each day and location independently. Using the serially complete dataset, a grid with a 5 × 5 km spatial resolution was constructed by estimating daily precipitation amounts and their corresponding uncertainty at each grid node. Daily precipitation estimations were compared to original observations to assess the quality of the gridded dataset. Four daily precipitation indices were computed to characterise the spatial distribution of daily precipitation and nine extreme precipitation indices were used to describe the frequency and intensity of extreme precipitation events. The Mediterranean coast and the Central Range showed the highest frequency and intensity of extreme events, while the number of wet days and dry and wet spells followed a north-west to south-east gradient in peninsular Spain, from high to low values in the number of wet days and wet spells and reverse in dry spells. The use of the total available data in Spain, the independent estimation of precipitation for each day and the high spatial resolution of the grid allowed for a precise spatial and temporal assessment of daily precipitation that is difficult to achieve when using other methods, pre-selected long-term stations or global gridded datasets. SPREAD dataset is publicly available at https://doi.org/10.20350/digitalCSIC/7393

Dinámicas ambientales y paisajísticas ligadas al abandono rural del Supramediterráneo de Gúdar-Maestrazgo (Sistema Ibérico)

214 p

Los Pedregales (Lupiñén-Ortilla, Huesca): contribución al conocimiento del poblamiento altomedieval en la Hoya de Huesca

El conocimiento de la ocupación visigoda y paleoislámica en el valle del Ebro resulta un tanto difuso, más por falta de investigaciones y por la escasa visibilidad de los asentamientos, que por un efectivo despoblamiento. En este artículo presentamos los resultados de nuestras investigaciones en el yacimiento de Los Pedregales, en la provincia de Huesca, un conjunto complejo en el que se encuentran materiales de diversas cronologías (romanos, altomedievales, modernos…) junto con numerosas estructuras pétreas en un área completamente alterada por procesos erosivos. Una minuciosa prospección y la excavación de algunas estructuras en el marco de un estudio geoarqueológico, nos ha permitido explicar la ocupación principal del yacimiento como un campo de silos datado entre los siglos vi y ix, que aporta una nueva referencia para la comprensión de los paisajes rurales antiguos y las comunidades campesinas dispersas que los ocupan. En el artículo se describen e interpretan las estructuras, se estudian los materiales más relevantes, especialmente los cerámicos, y se contextualiza el yacimiento con relación al poblamiento y los procesos históricos que afectan a este territorio

Drought Sensitiveness on Forest Growth in Peninsular Spain and the Balearic Islands

Drought is one of the key natural hazards impacting net primary production and tree growth in forest ecosystems. Nonetheless, tree species show different responses to drought events, which make it difficult to adopt fixed tools for monitoring drought impacts under contrasting environmental and climatic conditions. In this study, we assess the response of forest growth and a satellite proxy of the net primary production (NPP) to drought in peninsular Spain and the Balearic Islands, a region characterized by complex climatological, topographical, and environmental characteristics. Herein, we employed three different indicators based on in situ measurements and satellite image-derived vegetation information (i.e., tree-ring width, maximum annual greenness, and an indicator of NPP). We used seven different climate drought indices to assess drought impacts on the tree variables analyzed. The selected drought indices include four versions of the Palmer Drought Severity Index (PDSI, Palmer Hydrological Drought Index (PHDI), Z-index, and Palmer Modified Drought Index (PMDI)) and three multi-scalar indices (Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Precipitation Index (SPI), and Standardized Precipitation Drought Index (SPDI)). Our results suggest that—irrespective of drought index and tree species—tree-ring width shows a stronger response to interannual variability of drought, compared to the greenness and the NPP. In comparison to other drought indices (e.g., PDSI), and our results demonstrate that multi-scalar drought indices (e.g., SPI, SPEI) are more advantageous in monitoring drought impacts on tree-ring growth, maximum greenness, and NPP. This finding suggests that multi-scalar indices are more appropriate for monitoring and modelling forest drought in peninsular Spain and the Balearic Islands

Anisotropy of magnetic susceptibility of the Pyrenean granites

In this paper, we report on a compilation of more than 2200 sites (more than 10,000 individual measurements) where anisotropy of magnetic susceptibility (AMS) was studied in granites from the Variscan Pyrenees. The standardization and homogenization of this information has allowed us to produce three Main Maps that synthesize all the information related with the AMS of the Pyrenean granites. We also describe the problems found during the construction of the database (variable geo-positioning, different published information, etc.). The information derived from 21 granite bodies, the database, and the synthesis maps (magnetic susceptibility, Km, and the orientation of the magnetic foliation, plane perpendicular to k3, and of the magnetic lineation, k1) allow us to see for the first time a complete image of this important kinematic and petrographic indicator

Tree growth response to drought partially explains regional-scale growth and mortality patterns in Iberian forests

Tree-ring data has been widely used to inform about tree growth responses to drought at the individual scale, but less is known about how tree growth sensitivity to drought scales up driving changes in forest dynamics. Here, we related tree-ring growth chronologies and stand-level forest changes in basal area from two independent data sets to test if tree-ring responses to drought match stand forest dynamics (stand basal area growth, ingrowth, and mortality). We assessed if tree growth and changes in forest basal area covary as a function of spatial scale and tree taxa (gymnosperm or angiosperm). To this end, we compared a tree-ring network with stand data from the Spanish National Forest Inventory. We focused on the cumulative impact of drought on tree growth and demography in the period 1981–2005. Drought years were identified by the Standardized Precipitation Evapotranspiration Index, and their impacts on tree growth by quantifying tree-ring width reductions. We hypothesized that forests with greater drought impacts on tree growth will also show reduced stand basal area growth and ingrowth and enhanced mortality. This is expected to occur in forests dominated by gymnosperms on drought-prone regions. Cumulative growth reductions during dry years were higher in forests dominated by gymnosperms and presented a greater magnitude and spatial autocorrelation than for angiosperms. Cumulative drought-induced tree growth reductions and changes in forest basal area were related, but initial stand density and basal area were the main factors driving changes in basal area. In drought-prone gymnosperm forests, we observed that sites with greater growth reductions had lower stand basal area growth and greater mortality. Consequently, stand basal area, forest growth, and ingrowth in regions with large drought impacts was significantly lower than in regions less impacted by drought. Tree growth sensitivity to drought can be used as a predictor of gymnosperm demographic rates in terms of stand basal area growth and ingrowth at regional scales, but further studies may try to disentangle how initial stand density modulates such relationships. Drought-induced growth reductions and their cumulative impacts have strong potential to be used as early-warning indicators of regional forest vulnerability.This study was financially supported by Xunta de Galicia, Grant/Award Number PGIDIT06PXIB502262PR, GRC GI-1809; INIA, Grant/Award Number RTA2006-00117; CANOPEE, 2014-2020-FEDER funds, Spanish Science Ministry RTI2018-096884-B-C31, RTI2018-096884-B-C33, AGL2017-83828-C2-2R, RTI2018-096884-B-C3,1 and RTI2018-096884-B-C32 projects. Gabriel Sangüesa-Barreda was supported by a “Juan de la Cierva-Formación” grant from MINECO (FJCI 2016-30121). Antonio Gazol and Paloma Ruiz-Benito were supported by a project “2018 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation.” Ana-Maria Hereş was supported by the project PN-III-P1-1.1-TE-2019-1099 financed by the Romanian Ministry of Education and Research through UEFISCDI. Raúl Sánchez-Salguero was supported by VULBOS project (UPO-1263216, FEDER Funds, Andalusia Regional Government, Consejería de Economía, Conocimiento, Empresas y Universidad 2014-2020). Paloma Ruiz-Benito was supported by the Community of Madrid Region under the framework of the multi-year Agreement with the University of Alcalá (Stimulus to Excellence for Permanent University Professors, EPU-INV/2020/010) and the University of Alcalá “Ayudas para la realización de Proyectos para potenciar la Creación y Consolidación de Grupos de Investigación.” Andrea Hevia was supported by PinCaR project (UHU-1266324, FEDER Funds, Andalusia Regional Government, Consejería de Economía, Conocimiento, Empresas y Universidad 2014-2020).Peer reviewe