Appendix D. Mean values of the Palmer Drought Severity Index (PDSI) for the Yellowstone region for each of the five-year periods over which ring widths were regressed against stand density.
Model age |
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300 years |
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220 years |
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125 years |
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70 years |
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12 years |
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Notes: Values above the diagonal represent the periods for which the PDSI is reported in the corresponding cells below the diagonal. Positive values of the PDSI represent weather wetter than normal; negative values indicate weather drier than normal. Mean PDSI for the period of 1700–1995 was 0.234 (SD = 1.855).