Stand Structure in a Heterogeneous Old-growth Norway Spruce (Picea abies (L.) Karst.) Forest in Northern Sweden

Abstract: This study investigate the growth trend in an unmanaged Norway spruce forest in Västerbotten Country, Sweden. The result indicate that relationship between the diameter at breast height (1.3 m) and height follow a statistical significant trendline, where taller trees also represent wider tree diamater. The diameter hade a lower correlation to tree age, indicating that some trees in this area can have been suppressed for a time or have experience periods of high competition. Climate data (temperature, precipitation and North Atlantic oscillation) seem to have had only a partial (<50%) effect on the tree growth during two 40-years period. North Atlantic Oscillation showed no correlation with any tree chronology (standard and residual) during the past 160 years. A principle component analysis (PCA) were conducted, where the two strongest components corresponded to a cumulative variance equal to 55.5%. No chronology based on the two strongest components could fully explain the interaction between past climate and the tree ring growth detected in the study area.