date: Wed, 18 Feb 2009 05:19:30 -0500 (EST) from: k.briffa@uea.ac.uk subject: Invitation to Review for The Holocene to: t.m.melvin@uea.ac.uk 18-Feb-2009 Dear Dr. Melvin: Manuscript ID HOL-08-0088 entitled "A summer temperature proxy from height increment of Scots pine since 1561 at the northern timberline in Fennoscandia" has been submitted to The Holocene. I invite you to review this manuscript. The abstract appears at the end of this letter. Please let me know as soon as possible if you will be able to accept my invitation to review. If you are unable to review at this time, I would appreciate you recommending another expert reviewer. You may e-mail me with your reply or click the appropriate link at the bottom of the page to automatically register your reply with our online manuscript submission and review system. Once you accept my invitation to review this manuscript, you will be notified via e-mail about how to access Manuscript Central, our online manuscript submission and review system. You will then have access to the manuscript and reviewer instructions in your Reviewer Center. I realize that our expert reviewers greatly contribute to the high standards of the Journal, and I thank you for your present and/or future participation. Sincerely, Prof. Keith Briffa Associate Editor The Holocene To respond automatically, click below: Agreed: http://mc.manuscriptcentral.com/holocene?URL_MASK=hcyR82RdcGZFyPQ9Bjnj Declined: http://mc.manuscriptcentral.com/holocene?URL_MASK=4dtkN7tr2m3HwrqC2Pfs Unavailable: http://mc.manuscriptcentral.com/holocene?URL_MASK=y8ZPrSYBZX62GKQdmxbH MANUSCRIPT DETAILS TITLE: A summer temperature proxy from height increment of Scots pine since 1561 at the northern timberline in Fennoscandia ABSTRACT: Height increments of 60 Scots pine (Pinus sylvestris L.) trees were used to reconstruct mean June–August temperature variability at interannual-to-decadal scales from 1561 to 2004. Three standardization methods (67 %, 33% flexible splines, and a fixed 22 years spline) were compared in building chronologies in order to optimize the frequency response in relation to major climatic forcing factors. The height-growth chronology built using the 33% spline standardization proved to have the most consistent and time-stable relationship with the summer temperatures. Among the monthly precipitation and temperature variables from previous June to current August, previous July shows the highest correlation with height growth. In addition, both previous June and previous August have significant positive correlations. Our final transfer model accounts for 32.5% of the dependent instrumental temperature variance between 1909 and 2004. The Fourier spectra of the height-growth chronology and mean summer temperature are very similar in appearance, both series having peaks at 2.7–3.2 years, 6.7 yearss, and 15.7 years. Thus, the 444 years long summer temperature reconstruction is limited to high and medium frequencies. The coldest three summers in this record were experienced in years 1601, 1790 and 1903. Correspondingly, the summers of 1626, 1689 and 1598 were the warmest. The 1820s experienced the warmest 10-year mean, while the first decade of the 20th century was the coldest. Among the fourteen non-overlapping 30-year periods between 1561 and 1980 the period 1621–1650 was the warmest and the period 15911–1620 the coldest.