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Pith to bark: Building chronologies of Pinus ponderosa and Pseudotsuga menziesii at Apex Mountain, B.C.
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Pith to bark: Building chronologies of Pinus ponderosa and Pseudotsuga menziesii at Apex Mountain, B.C. Arford, M., Carilli, J., Chappell, B., Carter, G., Gonçalves, G., Hupy, C., Leland, C., Luszczynski, B., McDonald, S., Mather, V., Nesbitt, J., O’Brien, M., Sakulich, J., Speer, J., Spond, M., Stewart, T., Stott, K., Thomas, B., Van De Veer, R., Wixom, J.
Objectives • To learn the process of crossdating • Initial dating of cores • Creating a skeleton plot and using the list method to indicate marker years • Measuring tree-ring width in order to use COFECHA and ARSTAN to statistically verify crossdating
Objectives • To learn the process of sample collection and preparation • Site selection • Tree coring • Sample identification and storage • Mounting and sanding cores
Objectives • To learn data analysis techniques for tree-ring chronologies • Do Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) have different growth responses to climate?
Study Site • MOO lies within a mid-elevation transition zone between Douglas-fir and ponderosa pine • Cattle grazing area • Evidence of past logging
MethodsField Collection Targeted Sampling • Standing old trees • Trees growing on sensitive sites
MethodsField Collection Increment borers used to remove samples • 61 cores from Douglas-fir • 43 cores from ponderosa pine Data collection and Storage
MethodsSample Preparation • Cores mounted • Cut core mounts into individual samples
MethodsSample Preparation Sanding using progressively finer sandpaper • 220 grit • 320 grit • 30 microns • 9 microns
MethodsLab Techniques • Bark Present • Dating from bark to pith • Bark Absent • Using a skeleton plot to identify marker rings
MethodsLab Techniques • Crossdating • Skeleton plots • List method
MethodsRing Measurement • Annual growth rings measured to an accuracy of 0.005 mm • MeasureJ2X • Velmex measuring system
MethodsStatistical Analysis • COFECHA • Confirm core dating • ARSTAN • Removal of age-related growth trend • Reduction of noise to highlight climate signal
Conclusion • Ring widths from both species correlated with monthly precipitation • Negative exponential detrending resulted in slightly higher correlations. • Ponderosa pine correlated with summer precipitation (0.443) and with annual precipitation (0.474) • Douglas-fir correlated with spring precipitation (0.415)
Acknowledgements • National Science Foundation • Apex Mountain Resort • British Columbia Forest Service • Canadian Forest Service • U.S. Forest Service • University of British Columbia • University of Northern British Columbia • University of Victoria • University of Guelph • University of Tennessee • Indiana State University • Tree Ring Society • North American Dendroecological Fieldweek
Special Thanks to… Jim John and Mark