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

A ring-width and light-ring chronology was built from timberline spruce [Pi cea abies CL.) Karst.] in the eastern Alps in Austria. Comparison of the ch ronology spanning the period from 1750 to 1997 with a long-term temperature record revealed a close relationship between September and October tempera tures and light-ring occurrence. Tracheidogram analysis of radial tracheid diameter and cell-wall thickness of light rings formed in 1912 compared wit h a reference year confirmed the influence of temperatures of this period o n light-ring formation. It is concluded that light rings in timberline spru ce are painters for abnormally low temperatures during the last part of the growing season.