Acta Univ Latv (2007) 723: 163–170

Scots pine pointer-years in northwestern Latvia and their relationship with climatic factors

Abstract

At six sampling sites in northwestern Latvia Scots pines (Pinus sylvestris L.) were cored to obtain tree-ring width data and determine site pointer-year values (years with markedly wider or narrower tree-ring width compared to neighboring tree-rings). Correlation analysis was performed between pointer-year values and climatic factors (mean temperatures and precipitation sum) to determine significant relationships. There were only three years (negative 1940 and 1969, positive 1957), when all sampling sites had common pointer-years. The main climatic factors influencing development of pointer-years were February mean temperatures and June precipitation sum. Pointer-year development is mainly determined by local factors.