A reconstruction of mid–summer temperatures from ring–widths of scots pine since ad 50 in northern fennoscandia

Abstract

We have reconstructed mid–summer (July) temperatures using a master ring–width chronology of Scots pine (Pinus sylvestris L.) for northern Fennoscandia, covering nearly the last two millennia. The chronology is constructed from 93 living trees and 275 dead trees collected between 68 ∘ and 70 ∘ N, 20 ∘ and 30 ∘ E. In standardization, negative exponential functions and, alternatively, regression lines were applied. Because of a strong autocorrelation in the data, we used a model structure including 2–year lagging and a 3–year leading predicter along with the master chronology in the transfer function. Over one–half of the dependent climate variance was retrieved in our final reconstruction model. We indicate the largest temperature anomalies of individual summers as well as longer–term temperature variability starting from ad 50.