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Abstract
Ninety-two cross-sectional discs were extracted from tilted trees growing in hummocky and non-hummocky permafrost terrain near Mayo, Yukon Territory, in order to investigate the development of compression wood between 1900 and 2000. Chronologies were constructed by calculating the percentage of trees showing compression wood in each year of the record. Trees growing at the hummocky site showed increased compression wood for 1908–11 and 1964–70. Climate conditions during these periods may have increased soil moisture, leading to greater frost action and increased tilting. Trees at the non-hummocky site showed increased compression wood for 1924–31, 1936–46, and 1956–63. There is no consistent climate signal associated with these periods. Periodic flooding of Stewart River may have increased soil moisture at this site resulting in greater cryoturbation, and increased compression-wood formation.
