West Dummerston Covered Bridge historical, Vermont - vt011 Additional Site Information C. Baisan Reference: Pederson, N., A.R. Bell, E.R. Cook, U. Lall, N. Devineni, R. Seager, K. Eggleston, and K.J. Vranes. In press 2013. Is an Epic Pluvial Masking the Water Insecurity of the Greater New York City Region? Journal of Climate, Early Online Release 2012 doi: http://dx.doi.org/10.1175/JCLI-D-11-00723.1 Notes: This collection of Tsuga canadensis raw ring widths was made from the West Dummerston Covered Bridge in Dummerston, VT by C. Baisan. Construction was in 1870 [following the flood of 1869]. The timber are possibly from Mt. Ascutny near Windsor. While we cannot say much about the original forest from which these timbers originated, it is not a stretch to consider detrending these raw data with closed-canopy or forest interior conditions in mind given eastern hemlock’s basic life-history traits and typical growth patterns. For the Pederson et al. (2012) paper, these data were combined with the Pack Forest (Tsuga canadensis) data that are accessible in the ITRDB. COFECHA output: Chronology file name : VT011.CRN Measurement file name : VT011.RWL Date checked : 29JAN13 Checked by : B. Bauer Beginning year : 1557 Ending year : 1847 Principal investigators: C. Baisan Site name : West Dummerston Covered Bridge historical Site location : Vermont Species information : TSCA EASTERN HEMLOCK Latitude : 4256 Longitude : -7237 Elevation : M Series intercorrelation: 0.566 Avg mean sensitivity : 0.228 Avg standard deviation : 0.500 Avg autocorrelation : 0.913 Number dated series : 4 Segment length tested : 50 Number problem segments: 3 Pct problem segments : 8.82 PART 5: CORRELATION OF SERIES BY SEGMENTS: West Dummerston Covered Bridge histo 09:38 Tue 29 Jan 2013 Page 5 ----------------------------------------------------------------------------------------------------------------------------------- Correlations of 50-year dated segments, lagged 25 years Flags: A = correlation under .3281 but highest as dated; B = correlation higher at other than dated position Seq Series Time_span 1575 1600 1625 1650 1675 1700 1725 1750 1775 1800 1624 1649 1674 1699 1724 1749 1774 1799 1824 1849 --- -------- --------- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 1 DBC13 1694 1829 .20B .21B .41 .51 .57 .63 2 DBC17A 1603 1838 .76 .81 .72 .72 .62 .58 .51 .54 .67 3 DCB20A 1557 1805 .28A .70 .73 .51 .48 .46 .66 .52 .53 4 DBC24A 1581 1847 .34 .67 .71 .65 .65 .51 .54 .53 .52 .65 Av segment correlation .31 .71 .75 .63 .51 .45 .55 .52 .54 .65 PART 7: DESCRIPTIVE STATISTICS: West Dummerston Covered Bridge historica 09:38 Tue 29 Jan 2013 Page 8 ----------------------------------------------------------------------------------------------------------------------------------- Corr //-------- Unfiltered --------\\ //---- Filtered -----\\ No. No. No. with Mean Max Std Auto Mean Max Std Auto AR Seq Series Interval Years Segmt Flags Master msmt msmt dev corr sens value dev corr () --- -------- --------- ----- ----- ----- ------ ----- ----- ----- ----- ----- ----- ----- ----- -- 1 DBC13 1694 1829 136 6 2 .451 1.15 2.83 .780 .941 .204 2.62 .480 -.027 2 2 DBC17A 1603 1838 236 9 0 .672 .71 2.53 .495 .896 .228 2.72 .406 .029 1 3 DCB20A 1557 1805 249 9 1 .508 .66 1.90 .436 .935 .213 2.68 .335 .012 3 4 DBC24A 1581 1847 267 10 0 .580 .64 3.05 .422 .893 .253 2.60 .434 -.012 1 --- -------- --------- ----- ----- ----- ------ ----- ----- ----- ----- ----- ----- ----- ----- -- Total or mean: 888 34 3 .566 .74 3.05 .500 .913 .228 2.72 .406 .003