Tendencias radiales de la densidad y sus componentes en Pinus nigra Arn. de la Península Ibérica

Radial trends of wood density, earlywood density, latewood density and latewood proportion in Pinus nigra Arn. are fitted in juvenile wood and mature wood by means of a cubic-linear segmented regression model. This method allows to compare radial trends and to estimate the transition age between juvenile and mature wood. Latewood density and latewood proportion determine wood density and peculiar technologic characteristics of European black pine wood. None significant effect are found between two analyzed provenances (Serranía de Cuenca and Sierras de Cazorla-Segura), but some differences between sites were related to genetic or environmental factors. Site index has a more significant influence on wood density and latewood proportion than earlywood density and latewood density. This unknown effect in bibliography is discussed and the importance of latewood proportion on radial and axial wood patterns is showed.Las tendencias radiales de la densidad media del anillo y sus componentes: densidades de las maderas inicial y final y textura en Pinus nigra Arn. son ajustadas a las maderas juvenil y madura mediante un modelo cúbico-lineal de regresión segmentada. Este método permite comparar las tendencias radiales y estimar la edad de transición entre las maderas juvenil y madura. La densidad de la madera final y la textura determinan la densidad media del anillo y las peculiares características tecnológicas de la madera de Pinus nigra Arn. No se encuentran efectos significativamente diferentes entre las dos procedencias analizadas (Serranía de Cuenca y Sierras de Cazorla-Segura), pero algunas diferencias entre localidades son relacionadas con los factores genéticos o ambientales. La calidad de estación tiene una influencia más significativa sobre la densidad media del anillo y la textura que sobre las densidades de las maderas inicial y final. Se discute este efecto no reflejado en la bibliografía y se evidencia la importancia de la textura en los patrones radiales y axiales de esta madera

Tendencias radiales de la densidad y sus componentes en Pinus nigra Arn. de la Península Ibérica

Las tendencias radiales de la densidad media del anillo y sus componentes: densidades de las maderas inicial y final y textura en Pinus nigra Arn. son ajustadas a las maderas juvenil y madura mediante un modelo cúbico-lineal de regresión segmentada. Este método permite comparar las tendencias radiales y estimar la edad de transición entre las maderas juvenil y madura. La densidad de la madera final y la textura determinan la densidad media del anillo y las peculiares características tecnológicas de la madera de Pinus nigra Arn. No se encuentran efectos significativamente diferentes entre las dos procedencias analizadas (Serranía de Cuenca y Sierras de Cazorla-Segura), pero algunas diferencias entre localidades son relacionadas con los factores genéticos o ambientales. La calidad de estación tiene una influencia más significativa sobre la densidad media del anillo y la textura que sobre las densidades de las maderas inicial y final. Se discute este efecto no reflejado en la bibliografía y se evidencia la importancia de la textura en los patrones radiales y axiales de esta madera

Tree-rings, forest history and cultural heritage Current state and future prospects of dendroarchaeology in the Iberian Peninsula

We review the current state of dendroarchaeology in the Iberian Peninsula and discuss its potential, outlining the particular relevance and complexity of this territory and its material heritage for dendroarchaeological studies. Whereas dendrochronology is used throughout the rest of Europe to answer questions about cultural heritage, the application of dendroarchaeology in the Iberian Peninsula has been remarkably underrepresented in comparison to dendroecology and dendroclimatology. Existing tree-ring chronologies in this territory have a widespread geographical coverage, but are often too short to allow dendroarchaeological studies, resulting in inadequate assessments of material heritage made of wood in and originating from the Iberian Peninsula. However, different studies have demonstrated that dendroarchaeology has a great potential in the area. This review illustrates the rich variety of Iberian material heritage from different periods and cultures covering over 8000 years that could profit from dendrochronological research. Future research possibilities in relation to the available Iberian heritage in Spain, Portugal and worldwide are proposed. © 2015

Double magnetic phase transition in ND4Fe(DPO4)2 and NH4Fe(HPO4)2

Combining neutron diffraction, magnetization measurements up to 330 kOe and specific-heat data, we have studied in detail both the crystal and magnetic structures of triclinic ND4Fe(DPO4)2 and NH4Fe(HPO4)2 compounds. The low symmetry of this structure gives rise to a complex pattern of competing superexchange interactions between the magnetic moments of two types of Fe3+ sites (with different site symmetry) that are responsible for the existence of two magnetic phase transitions. Below TC=17.82±0.05K ND4Fe(DPO4)2 orders ferrimagnetically with the magnetic moments lying in the crystallographic plane ac. As the temperature is lowered to Tt=3.52±0.05K the compound undergoes a magnetic phase transition to an equal moment antiphase structure characterized by the propagation vector close to →kAF≈(1/16,0,1/16) and a magnetic moment for the Fe3+ ions of 4.8μB at 1.89 K. In addition, a two-step metamagnetic process is observed in the magnetization measurements at 2 K, where the antiphase ordering is destroyed under a field of only 2 kOe and the compound recovers the high-temperature ferrimagnetic ordering at around 20 kOe. The stability of this ferrimagnetic phase under magnetic field is only broken when the strength of the field reaches values as large as 180 kOe, and the magnetic moments begin to rotate to reach the full-induced ferromagnetic structure. A mean-field model has been used to account for the magnetization process leading to an estimation of the molecular-field coefficient of −2.86 K and the value of the critical magnetic field of 535 kOe to attain the full-induced ferromagnetic phase.This work has been carried out with the financial support of FEDER-MEC (Grants No. MAT2006-01997, No. MAT2008-06542-C04), and Factoría Española de Cristalización Consolider Ingenio 2010. Part of this work has been supported by EuroMagNet under the EU under Contract No. 228043.Peer reviewe