title: Effects of Recent Minimum Temperature and Water Deficit Increases on Pinus pinaster Radial Growth and Wood Density in Southern Portugal.
abstract: Western Iberia has recently shown increasing frequency of drought conditions coupled with heatwave events, leading to exacerbated limiting climatic conditions for plant growth. It is not clear to what extent wood growth and density of agroforestry species have suffered from such changes or recent extreme climate events. To address this question, tree-ring width and density chronologies were built for a Pinus pinaster stand in southern Portugal and correlated with climate variables, including the minimum, mean and maximum temperatures and the number of cold days. Monthly and maximum daily precipitations were also analyzed as well as dry spells. The drought effect was assessed using the standardized precipitation-evapotranspiration (SPEI) multi-scalar drought index, between 1 to 24-months. The climate-growth/density relationships were evaluated for the period 1958-2011. We show that both wood radial growth and density highly benefit from the strong decay of cold days and the increase of minimum temperature. Yet the benefits are hindered by long-term water deficit, which results in different levels of impact on wood radial growth and density. Despite of the intensification of long-term water deficit, tree-ring width appears to benefit from the minimum temperature increase, whereas the effects of long-term droughts significantly prevail on tree-ring density. Our results further highlight the dependency of the species on deep water sources after the juvenile stage. The impact of climate changes on long-term droughts and their repercussion on the shallow groundwater table and P. pinaster's vulnerability are also discussed. This work provides relevant information for forest management in the semi-arid area of the Alentejo region of Portugal. It should ease the elaboration of mitigation strategies to assure P. pinaster's production capacity and quality in response to more arid conditions in the near future in the region.
authors: Instituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa Lisboa, Portugal.
authors: Cathy B
authors: CB
authors: Kurz-Besson
authors: Centro de Investigação e de Tecnologias Agro-Ambientais e Biológicas, Universidade de Trás-os-Montes e Alto Douro Vila Real, Portugal.
authors: José L
authors: JL
authors: Lousada
authors: Biosystems and Integrative Sciences Institute, Universidade de Lisboa Faculdade de CiênciasLisboa, Portugal; Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de LisboaLisboa, Portugal; Departamento de Genética e Biotecnologia, Universidade de Trás-os-Montes e Alto DouroVila Real, Portugal.
authors: Maria J
authors: MJ
authors: Gaspar
authors: Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de LisboaLisboa, Portugal; Instituto Nacional de Investigação Agraria e VeterináriaOeiras, Portugal.
authors: Isabel E
authors: IE
authors: Correia
authors: Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de LisboaLisboa, Portugal; Instituto Nacional de Investigação Agraria e VeterináriaOeiras, Portugal.
authors: Teresa S
authors: TS
authors: David
authors: Instituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa Lisboa, Portugal.
authors: Pedro M M
authors: PM
authors: Soares
authors: Instituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa Lisboa, Portugal.
authors: Rita M
authors: RM
authors: Cardoso
authors: Instituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa Lisboa, Portugal.
authors: Ana
authors: A
authors: Russo
authors: Instituto Dom Luiz, Faculdade de Ciências, Universidade de LisboaLisboa, Portugal; Centre National de Recherches Météorologiques, Meteo-France/CNRSToulouse, France.
authors: Filipa
authors: F
authors: Varino
authors: Instituto Dom Luiz, Faculdade de Ciências, Universidade de LisboaLisboa, Portugal; School of Physics and Astronomy, Monash University, ClaytonVIC, Australia.
authors: Catherine
authors: C
authors: Mériaux
authors: Instituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa Lisboa, Portugal.
authors: Ricardo M
authors: RM
authors: Trigo
authors: Instituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa Lisboa, Portugal.
authors: Célia M
authors: CM
authors: Gouveia
keywords: IADFs; SPEI drought index; climate change; dendrochronology; maritime pine; wood radial density; wood radial growth