Climatic significance of light rings in timberline spruce, Picea abies, Austrian Alps

Abstract

A ring-width and light-ring chronology was built from timberline spruce [Picea abies (L.) Karst.] in the eastern Alps in Austria. Comparison of the chronology spanning the period from 1750 to 1997 with a long-term temperature record revealed a close relationship between September and October temperatures and light-ring occurrence. Tracheidogram analysis of radial tracheid diameter and cell-wall thickness of light rings formed in 1912 compared with a reference year confirmed the influence of temperatures of this period on light-ring formation. It is concluded that light rings in timberline spruce are pointers for abnormally low temperatures during the last part of the growing season.