title: New star on the stage: amount of ray parenchyma in tree rings shows a link to climate.
abstract: Tree-ring anatomy reflects the year-by-year impact of environmental factors on tree growth. Up to now, research in this field has mainly focused on the hydraulic architecture, with ray parenchyma neglected despite the growing recognition of its relevance for xylem function. Our aim was to address this gap by exploring the potential of the annual patterns of xylem parenchyma as a climate proxy. We constructed ring-width and ray-parenchyma chronologies from 1965 to 2004 for 20 Juniperus thurifera trees growing in a Mediterranean continental climate. Chronologies were related to climate records by means of correlation, multiple regression and partial correlation analyses. Ray parenchyma responded to climatic conditions at critical stages during the xylogenetic process; namely, at the end of the previous year's xylogenesis (October) and at the onset of earlywood (May) and latewood formation (August). Ray parenchyma-based chronologies have potential to complement ring-width chronologies as a tool for climate reconstructions. Furthermore, medium- and low-frequency signals in the variation of ray parenchyma may improve our understanding of how trees respond to environmental fluctuations and to global change.
authors: Departamento de Ciencias Agroforestales, EU de Ingenierías Agrarias, Universidad de Valladolid, Los Pajaritos s/n, Soria, E-42004, Spain.
authors: José Miguel
authors: JM
authors: Olano
authors: Departamento de Biología Vegetal y Ecología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Barrio Sarriena s/n, E-48940, Leioa, Spain.
authors: Alberto
authors: A
authors: Arzac
authors: Departamento de Ciencias Agroforestales, EU de Ingenierías Agrarias, Universidad de Valladolid, Los Pajaritos s/n, Soria, E-42004, Spain.
authors: Ana I
authors: AI
authors: García-Cervigón
authors: Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland.
authors: Georg
authors: G
authors: von Arx
authors: Misión Biológica de Galicia, Consejo Superior de Investigaciones Científicas (MBG-CSIC), Apdo. 28, 36080, Pontevedra, Spain.
authors: Vicente
authors: V
authors: Rozas
mesh_terms: D002980:Climate; D005843:Geography; D018653:Juniperus / Q000033:anatomy & histology* / Q000254:growth & development*; D019083:Mediterranean Region; D012044:Regression Analysis; D013997:Time Factors; D014197:Trees / Q000033:anatomy & histology* / Q000254:growth & development*; D052584:Xylem / Q000033:anatomy & histology* / Q000254:growth & development*