1 / 25

A dendroclimatic analysis of Chestnut oak in SW Virginia

A dendroclimatic analysis of Chestnut oak in SW Virginia. Andria Dawson Bronwyn Gillanders Chika Sakata David Austin David Walker Sarah Appleton Shelly Griffin Valerie Trouet. Outline. Objectives Site selection & sampling methods Detrending & building chronology

hazina
Download Presentation

A dendroclimatic analysis of Chestnut oak in SW Virginia

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. A dendroclimatic analysis of Chestnut oak in SW Virginia Andria Dawson Bronwyn Gillanders Chika Sakata David Austin David Walker Sarah Appleton Shelly Griffin Valerie Trouet

  2. Outline • Objectives • Site selection & sampling methods • Detrending & building chronology • Comparing climate data with chronology • Correlating regional chronologies • Summary & future research

  3. Objectives • Create a chronology for Quercusprinus,chestnut oak. • Investigate climatic influences on chestnut growth chronology. • Determine relationships with other chronologies & develop a regional chronology.

  4. Site Selection Dendroclimatic sampling strategy • High elevation, steep slope • Availability of older canopy trees • Little human influence Tree Selection • Large diameter • Flattened crown • Highly sinuous stem • No lower branches • Trees with little impact from other factors

  5. 37  22.2’ N 80  14.8’ W Elevation: 1830 ft North facing slope • Upland oak pine forest • chestnut oak • scarlet oak • northern red oak • red maple • Virginia pine • pitch pine • eastern white pine

  6. Methods Cored 36 chestnut oak Two cores / tree at 180 

  7. Sanding, crossdating & measuring

  8. Cross-date Cores • Visually & statistically cross-dated cores with a combination of • Skeleton plots & list method • TSAP • COFECHA

  9. Detrending Used smoothing spline with 50% cutoff

  10. Earliest increment1759 • 53 series from 31 trees in chronology • 12 series were not included in the chronology • Interseries correlation: 0.563 • Mean sensitivity: 0.209

  11. Final Chronology, Sample Depth & EPS Final chronology Sample depth Expressed population signal

  12. Climate Analyses • Compare chronology with climatic parameters • Temperature • Precipitation • Palmer Drought Severity Index • Sea level pressure • Geopotential height • Oscillation indices (ENSO, NAO, SOI, AMO, AO, AMOC, PDA, etc) • Using weather station & gridded data • Blacksburg Weather Station data • 1891-2006 (temperature & precipitation); • 1869-2006 (PDSI)

  13. p<0.05 p<0.05

  14. Palmer Drought Severity Index - Season r = 0.3768

  15. Precipitation Window midpoint r = 0.46

  16. Post 1950 Temperature Temperature: September correlation Window midpoint r = -0.29 Pre 1950

  17. Spectral & Wavelet Analyses 11 16.5 10.3 Chestnut Oak Chronology Precipitation • Both have strong 10-11 year period cycles in data • May precipitation may be a key driver

  18. Regional Chronologies • 14 chronologies were correlated with our chronology • 3 white oak, 11 chestnut oak • 9 correlations were significant • 8 chronologies were used in a Principal Component Analysis (PCA) to look for a regional trend

  19. Regional Chronology Comparison Charlottesville Brush Mountain Spur NADEF 2011 Lynn Hollow Craig Creek Watch Dog Mountain Otter Creek Blue Ridge Parkway

  20. PCA results Component 2 • PCA 1 – 37.1% of variance • PCA 2 – 16.2% of variance Component 1

  21. Correlations between PCA 1 and climate parameters p<0.05 p<0.05

  22. SUMMARY • Built a chestnut oak chronology back to 1845 • Correlated our chronology with climate data & found that • Early summer PDSI & precipitation – positive • Sept temperature – negative • Strong regional correlation suggests that precipitation is a driver • Approximately 11 year periodicity in chronology & precipitation may be linked

  23. Future Research • Strong signal in regional chronology suggests may be possible to reconstruct climate • Extend chronology through use of archaeological samples • Further investigation of PCA2

  24. Acknowledgements • Jim Speer & Carolyn Copenheaver for organising fieldweek • Carolyn Copenheaver for providing chronologies • Peter Brown & Carolyn Copenheaver for financial support • Reece Brown for comedic relief

More Related