Bighorn Mountains Dendrochronology

Cook's Canyon in Tensleep Preserve, WY

Cook's Canyon is part of The Nature Conservancy's Tensleep Preserve near Tensleep, WY. Ponderosa pine is the dominant tree in and around the canyon, but limber pine and Douglas fir are also common. The oldest pines we cored are growing on the northern edge of the canyon near the canyon rim. Missing rings are common in cores from these pondersosa pines, and very few of our cores have all of the rings between 1890 and 1900. Additional samples will be required to strengthen the regional signal in these series and to improve confidence in the cross dating. The preliminary ring width chronology from these trees barely extends back to 1500 AD and appears to have a climatic signal for drought stress or precipitation that is weaker than at the other two sites. Cross dating of a core from one dead standing pine snag indicates that it died in about 1894 and was scarred by a fire in 1779. This suggests that future sampling of dead wood could extend the chronology and provide a record of past fires.

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  A ponderosa pine (TNC05) at the edge of the rim rock on the north side of Cook's Canyon. A core at its base includes 381 rings.
  Near the upper (eastern) end of Cook's canyon looking southeast. Most of the trees are ponderosa pines.
  A ponderosa pine at the edge of Cook's Canyon. This tree was not sampled.
  Steve Jackson is coring tree CCP01, the second oldest ponderosa pine sampled with an inner ring date of 1515.
  This burned snag of a ponderosa pine (CPT07) died in about 1894 and was scarred by a fire in about 1779.
  Some of the oldest pines were growing on exposed ledges where they were apparently protected from fire, logging, ranchers, and girl scouts.






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