Dendroclimatological investigation on Douglas fir (Pseudotsuga menziesii) in Lithuania

Abstract

Dendroclimatological research on Rocky Mountains Douglas fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and Green Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) - introduced trees in Lithuania - has been conducted. For the purpose of research 19 research plots on Douglas fir were selected. Tree-ring-widths were measured and local chronologies were constructed as bi-weight robust means. Compiled masterchronology covers 187 trees and spans from 1910 to 2004. Response function analysis has shown positive and significant influence of air temperature at the end of winter beginning of spring to the radial growth of Douglas fir, while the strong positive impact of precipitation in June prevails in the eastern Lithuania. Analysis on pointer years of the radial growth has indicated that depressions of the radial growth of Douglas fir are driven by colds in winter spring and droughts in summer. Increases of the radial growth are connected to warm winters and humid summers. Accordingly, conditions more favourable for the growth of Douglas fir are in the West Lithuania.[...].