A 481-year chronology of oak earlywood vessels as an age-independent climatic proxy in NW Iberia

作者：Souto Herrero Manuel; Rozas Vicente; Garcia Gonzalez Ignacio^*

来源：Global and Planetary Change, 2017, 155: 20-28.

DOI：10.1016/j.gloplacha.2017.06.003

• Dendrochronology
• Tree ring
• Quantitative wood anatomy
• Time stability
• Age trend
• Disturbance regime

The earlywood vessels of ring-porous trees can be analyzed dendrochronologically and used as a proxy for environmental information. However, most works deal with the analysis of contemporary climate-growth relationships and do not evaluate their long-term variation.
We obtained a 481-year chronology of earlywood vessel size of oak (Quercus robur L.) in the northwestern Iberian Peninsula, investigated its behavior through time, and compared it to a chronology of younger trees developed at the same site. We expressed earlywood vessel size as the hydraulically-weighted diameter (D-H) and discriminated between vessels in the first row (rl) and the rest of the vessels (nrl); radial increment was assessed from latewood width (LW).
Climate-growth relationships were strong and nearly identical for both age classes. Spring temperature positively affected vessel size, but only for the first row, probably mediating the onset of cambial activity. The chronology of old trees showed an almost flat age trend, except for the first decades, and series were not affected by stand dynamics. In contrast, LW had a weak response to climate, probably because of the high impact of abrupt growth changes. There was a high negative correlation between DH and the winter North Atlantic Oscillation Index (NAO), which was unstable during the 20th century.
To our knowledge, this is the longest chronology of earlywood vessel size obtained to date, and offers promising results, as this proxy is shown to be independent of age and forest disturbances, and was strongly correlated to climate across long time spans.

• 出版日期2017-8