992 resultados para Pinus nigra


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PREDICT POTENTIAL DISTRIBUTION. Spatial and temporal evolution of the species under different climate scenarios. Generation of habitat suitability models (HSM)  high degree of uncertainty and limitations. The importance of their validation has been stressed. In this work we discuss the present potential distribution of P. sylvestris and P. nigra in the Iberian Peninsula by using MaxEnt, and evaluate the influence of the different environmental variables. Our intention is to select a set of environmental variables that explains better their current distribution, to achieve the most accurate and reliable models. Then we project them to the past climatic conditions (21 to 0 kyrs BP), to evaluate the outputs with existing palaeo-ecological data.

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The presence of Pinus nigra in central Spain, where its natural populations are very rare, has led to different interpretations of the current vegetation dynamics. Complementary to the available palynological evidence, macroremains provide local information of high taxonomic resolution that helps to reconstruct the palaeobiogeography of a given species. Here we present new macrofossil data from Tubilla del Lago, a small palaeolake located at the eastern part of the northern Iberian Meseta. We identified 17 wood samples and 71 cones on the basis of their wood anatomy and morphology, respectively. S ome of the fossil samples were radiocarbon dated (~4.230-3210 years cal BP). The results demonstrate the Holocene presence of P. nigra in the study area, where it is currently extinct. This evidence, together with other published palaeobotanical studies, indicates that the forests dominated by P. nigra must have had a larger importance on the landscape prior to the anthropogenic influence on the northern Iberian Meseta.

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El presente proyecto se centra en el estudio de la influencia que ejerce el contenido de humedad en la madera sobre mediciones realizadas mediante diversos ensayos no destructivos (NDT – Non Destructive Tests-). El objetivo es encontrar la relación entre el contenido de humedad de la madera de varias especies del género Pinus (Pinus nigra Arn, Pinus radiata D.Don. y Pinus sylvestris Ait.) y los resultados de diferentes NDT (penetrómetro, resistencia al arranque de tornillos y velocidad de propagación de ondas inducidas y ultrasonidos), y en caso de existir, tratar de elaborar un modelo o factor de corrección que nos permita tener en cuenta dicha influencia en futuros NDT.