Date of Award


Degree Type


Degree Name

Master of Science




Luckman, Brian


This thesis investigates the variation of ring widths from 23 white spruce (Picea glauca) treeline chronologies located along the Dempster Highway (61-68°N), bracketing the position of the classical TTHH site (65.33°N) in the Yukon. Relationships between the 18 strongest chronologies and mean monthly/seasonal temperatures from Dawson over the 1900-2000 period were examined using correlation analyses. Ring-width chronologies were commonly negatively correlated with prior summer temperatures over the entire 20th century but most strongly in the 1950-2000 period. However, several sites had positive relationships with summer temperatures in the 1900-1950 period and much weaker or negative relationships with summer temperatures over the 1951-2000 period indicating an apparent “divergent” response over the 20th century. “Responder analysis” of three highly replicated sites indicated two were dominated by strong negative relationships with summer temperatures in the late 20th century but the northernmost site contained trees that maintained a positive relationship with summer temperatures in the late 20th century.



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